The BeeMonitor with permanent scale

The BeeMonitor prototype has been up and running sinds march 2017 without any big issue’s, in the mean time some hardware/software upgrades were made. A complete new Arduino compatible Arduino bootloader allows faster startup even at very low voltages.

Because the battery life was very promising I decided to add a load cell for a permanent scale and keep track of the beehive weight. The result is a wireless BeeMonitor + scale without external power or wires. The beehives can be placed everywhere within range of the gateway. Reference measurements indicate the two AAA batteries will keep the BeeMonitor powered for at least one year, collecting data every 15 minutes! Awesome!

Setup: BeeMonitor prototype with internal beehive temperature sensor and permanent half-scale

The scale is based on the half-scale principal. It’s designed to weigh only half the hive, making the design simpler because only 1 (high quality) load-cell is required. This design finally makes monitoring beehives affordable!

There’s a on-the-go calibration procedure. The scale can be calibrated in the field by following a couple of steps, without the need of re-programming.

Temperature graphs

The graph below shows the ambient temperature (outside beehive, shade) vs. beehive cluster temperature (inside beehive). Past days have been mostly wet with almost no sunshine. The cluster temperature dropped a few degrees what probably indicates the queen is laying much less eggs and the bees are preparing for a long cold period.

Ambient temperature (outside beehive, shade) vs. cluster temperature (inside beehive)

Weight graph

A couple of days before the beginning of this graph, the bees were given extra sugar water (the two steep drops in the graph are the removal of the empty sugar water reservoirs).

Due to the bad weather the bees don’t fly much and certainly don’t bring much food in. The weight drops because of the erratic weather, the number of bees is also reducing because they prepare for winter. The weight rises and decreases slightly within one day but the overall weight is decreasing.

The weight is displayed in grams, because of the half-scale design this is only the weight of half the hive. To know the total weight, it has to be multiplied by two. A future software upgrade will display the real weight.

Beehive weight in grams

Future plans

A revision/upgrade of the BeeMonitor is in development. Below the key features of the first version with the most important upgrades in the new version.

Key features

  • Atmega328p microcontroller (Arduino compatible)
  • 2 internal AAA batteries (3V)
  • Powerdown: 35 nA
  • Wakeup every 15′, 30′, 1h or 2h selected with internal dipswitch
  • Beehive ID selected with internal dipswitch (up to 15 hives without re-programming)
  • Low power 868 MHz radio with internal antenna (up to ± 250m), external antenna possible
  • Manual “wakeup” button
  • RGB led
  • Buzzer
  • Internal ambient temperature/humidity sensor
  • 2 RJ12 ports for external temperature/humidity beehive sensors


  • New, slightly larger housing
  • 3 RJ12 ports for temperature/humidity beehive sensors
  • Internal (removable) HX711 ADC module
  • Separate (pluggable) connector for beehive load-cell scale
  • Extra “calibrate button” for easy scale calibration
  • Even lower power consumption
  • Integrated boost converter to operate down to 1,8V

The current gateway is based on a Raspberry Pi, running open-source “Domoticz” software. This is actually home-automation software, because I had this running for other projects I chose to implement the BeeMonitor in Domoticz for the prototype.

Because this is not really a plug & play option for beehives, a new cheaper Wi-Fi, IoT (LoRaWAN) gateway needs to be developed to forward all data to an online platform. Analyzing all available options, seems the best option.

Questions? Don’t hesitate to contact me!

Upgraded LoRaWAN Node

The upgrade of my LoRaWAN Node is finally here!

The LoRaWAN Node is a compact, universal and affordable LoRaWAN Node with a powerful Arduino compatible Atmel Atmega1284P microcontroller. The dimensions are only 41 x 26 mm!

The new “TvB LoRaWAN Node Rev.2b” with RN2483A

The node supports the most popular LoRa transceivers like the RN2483/RN2903 and RFM95W variants.

It has the same features as the previous version but is’t more user friendly. Some other small changes were made to make for easier manufacturing.


  • Atmel Atmega1284P-AU (Arduino compatible)
  • 41 x 26 mm
Operating voltage
  • 3.3V (fixed LDO regulator)
I/O pins
  • 24 available pins (Digital I/O, Analog input, PWM, UART, SPI & I2C)
Flash memory
  • 128 KB (4x more than Arduino Uno)
  • 16 KB (8x more than Arduino Uno)
  • 4 KB (4x more than Arduino Uno)
  • 8 MHz
  • Max 6V DC input
  • Single cell 3.7V LiPo battery
  • (Solar) Charge controller for single cell Li-Ion & LiPo batteries with orange charging LED (up to 500mA charge current with max. 6V input)
  • Dimmable RGB LED + blue LED
Supported LoRaWAN transceivers
  • HopeRF RFM9X
  • Microchip RN2483 / RN2903 (High-band only)
  • U.FL and/or SMA connector, or a simple copper wire as antenna
  • 5 pin programming header for USB to Serial converter (individual jumper cables required!)
  • Default JST 2.0 battery connector
  • Build-in voltage divider for measuring battery state
  • Onboard reset switch
  • Breadboard compatible headers
  • Arduino library with starters examples
  • Low power sleep functions available (35uA in deep sleep)

Details about the previous version can be found here in this earlier post.

LoRa transceiver

As described above the hardware supports 2 different wireless LoRa modules. Yes! That means you can pick the one you like most!

U.FL or SMA antenna

Breadboard compatible



Interested in the hardware?

I’m now on Tindie!

I sell on Tindie

Check out the Tindie page of the TvB LoRaWAN Node

Tindie is ideal for small orders, please note that using Tindie is not “free” for me. If you’re interested in more than a couple of boards don’t hesitate to contact me for more info, better pricing & direct orders!

What’s included?

The hardware includes extra headers, SMA antenna connector, Arduino library, starters examples & support. Please note: You will need some soldering experience & a soldering iron with a round tip <= 1 mm.

Only shipping within Europe!

The “BeeMonitor” project

Beekeeping is a time consuming hobby, it’s not so easy as it sounds. Making sure the bees are healthy takes a lot of knowledge and experience.

Adding sensors to a beehive helps the beekeeper to monitor the hive and take action when things are not as expected.

Therefor I decided to make my own “BeeMonitor”. Starting with the electronics, connecting our hives to the internet!

The BeeMonitor with sensors

The technical side:

The BeeMonitor is a “battery powered wireless datalogger”. It’s a compact controller with user-changeable dipswitches, RGB led, buzzer, “plug & play” RJ12 connectors designed for different sensors combinations and is capable to carry 2 different wireless modules, a RFM69W for use in a private network or the RFM95W to connect to an LPWAN IoT network (LoRaWAN) on sub-gigahertz radio bands. Powered by 2 AAA battery’s, operating on 3V the”BeeMonitor” only consumes 35nA in sleep the making the battery’s last for years! Great, isn’t it?

Transmitted messages are received by a gateway, processed and stored in a database. Data can be shown on a website and even in online “live” graphs depending on the needs.

BeeMonitor with custom front

For example, some temperature & humidity data from one of our beehives:

Battery life:

The prototype has been up & running, collecting data for about 2 months now. So far the battery voltage has dropped from 3.17V to 3.12V without any (low power) software optimisation. Even without the battery will keep the BeeMonitor up & running for a very long time, all the way down to 1.9V. That’s when the voltage reaches the minimum operation voltage for some of the hardware.

Power consumption:

Measuring one wake-up cycle (about 2 seconds) gives a clear overview of the power consumption of the hardware. A short description of how things work here (reference: 1 mV = 1 mA):

  • 0 s: External input, interrupt or timer waking up a part of the hardware (50 nA)
  • 250 ms: Power enabled to other hardware (1.8 mA)
  • 320 ms: Microcontroller startup, bootloader (3.5 mA)
  • 1.7 s: Microcontroller running program, reading sensors, processing
  • 1.82 s: Sending message (50 mA)
  • 1.83 s: Waiting for ACK from gateway (18 mA)
  • 1.85 s: Blink green led (4 mA)
  • 2 s: Powerdown (35 nA)

This graph makes clear I need to optimize the bootloader, because it takes 1.38 s! Thats way to long for battery powered hardware.

Future plans:

There are some improvements needed such as an optimized bootloader, optimized software for better battery life, ..

September 2017: The prototype has been upgraded, read more about the plans & upgrades here.

LoRaWAN Node with onboard antenna

After the great succes with the default LoRaWAN Node I really wanted to design an inexpensive Node with an build-in antenna for small LoRaWAN use cases.


Good antenna’s are expensive!

When it comes to antenna’s, one thing is certain: Good antenna’s aren’t cheap.
I guess we all bought those crappy cheap antennas in the past to find out they are not designed for that frequency or don’t work at all..

Choosing for an onboard antenna makes you node compact an even more low cost. You don’t need those antenna connectors, cables and antennas. Any PCB based antenna won’t have the same range as an “real” antenna but the goal is to get about half the distance.

The new antenna: Ceramic chip or custom antenna design?

For an onboard antenna you can easily chose an ceramic chip antenna for the desired frequency. There are a lot of these antenna chips available and it doesn’t take a lot of experience to use them. They can save you most space on your PCB.

Ceramic chip antennas

Most of these chips are affordable but I decided to not use any chip antenna and design my own antenna!
Making the ideal antenna takes some time and a certain knowledge in electronics, HF and antenna’s. This includes everything from calculations, simulations, designing, prototyping, measuring, and modifying before the results are really satisfying.

The design

For the new Node I didn’t want to change anything from my existing proven “TvB LoRaWAN Node”. This limits the available space to a width of 26mm for the antenna.

Here’s the initial design I came up with:


Verifying, measuring, optimizing and testing the antenna design took a while but the result was worth it.
The final measurements concluded that the center frequency of the antenna design is about 20 MHz’s off the 868 MHz goal. So we’re not there yet.

That’s great, but what does that mean?

An design update, mostly based on measurements.
The most important thing of any antenna is the range. To get the maximum out of your antenna the center frequency has to match the desired frequency as best possible. This point will transmit the most RF energy resulting in a better range.

You can’t compare a lab measurement with an real world test so you always have to verify the range. After assembling the first prototype it’s time to put it to the test!


For range testing I simply hooked up an GPS module to the battery powered Node.
The Node receives a GPS location form the GPS module and transmits it’s location every 15 seconds over LoRaWAN.

When a message is received on the gateway(‘s) you can simply plot the distance between transmitter and receiver.
For testing purposes I used an RFM95W LoRa module from HopeRF, with the default LoRaWAN settings (SF12). That’s it!

The range, what can you expect from internal, microstrip antenna’s?

I didn’t expect much from a small antenna but I guess I’m wrong. LoRaWAN is a very impressive technology that’s able to send messages over many and many km’s.

Practical measurements with a regular node (default λ/4 antenna for 868 MHz) results in maximum ranges up to 20km and more in the ideal situation.
I guessed the range of the internal antenna would be around a couple of km’s with a maximum range of 5 km’s. Everything beyond that would be great.

Range test, the first test-drive

I didn’t expect much from the first range test-drive. In the message log I was hoping to find a couple of messages but there much more received messages than “just a couple”. Meaning only one thing: The Node works!

Analyzing all location data showed distances up to a whopping 9 km from inside the car!
All other range measurements confirmed this first impression.


I may decide that this node has a guaranteed range of about 5 km for LoRaWAN use cases in real world. Almost all messages within that radius are well received on the gateways.

The test data also showed that the antenna acts as a directional antenna, performing a little bit better in the one direction than the other. Unlike an default λ/4 antenna that radiates the same amount of energy in all directions.
The node has to be used with the antenna pointing upwards for the best results.

Hardware details


Work in progress

There’s still some space for improvement. Because the used frequency in Europe is 868MHz I’ve optimized the design for that exact frequency.
Based on the measurements on the first design I made a couple of different modified versions. The good news: some of them perform better than the first version because they have more gain on 868MHz.

TvB LoRaWAN Node

I’m getting a lot of response and technical questions about the new LoRaWAN Node.
With this post I hope to give a better overview of the Node hardware and features for those interested in building there own.


TvB LoRaWAN Node with RFM95W or RN2483 & Proto Shield

The LoRaWAN Node is a compact, universal and affordable LoRaWAN Node with a powerful Arduino compatible Atmel microcontroller.


  • Atmel Atmega1284P (Arduino compatible)
  • 40 x 25 mm
Operating voltage
  • 3.3V (onboard regulator)
I/O pins
  • 24 available pins (Digital I/O, Analog input, PWM, UART, SPI & I2C)
Flash memory
  • 128 KB (4x more than Arduino Uno)
  • 16 KB (8x more than Arduino Uno)
  • 4 KB (4x more than Arduino Uno)
  • 8 MHz
  • 5V USB power
  • Single cell 3.7V LiPo battery
  • (Solar) Charge controller IC with status LED, up to 500mA charge current (max. 6V input)
  • RGB LED + extra blue LED
Supported LoRaWAN modules
  • HopeRF RFM9X
  • Microchip RN2483 / RN2903 (High-band only)
  • U.FL and/or SMA connector
  • FTDI programming header for USB to Serial converter
  • Default JST 2.0 battery connector
  • Buid-in battery voltage divider for measuring battery state
  • Onboard reset switch
  • Breadboard compatible headers
The LoRaWAN Node is only 7.5 mm thick when used with an RN2483 LoRaWAN module.

The LoRaWAN Node is only 7.5 mm thick when used with an RN2483 LoRaWAN module (without JST battery connector).


Because I like to use different LoRaWAN modules depending on the project I’ve added support for the 2 most popular LoRaWAN modules:

  • TvB LoRaWAN Node – RFM95W
  • TvB LoRaWAN Node – RN2483 (LoRaWAN Certified)

Without any hardware modifications I can use one of these 2 modules.
The practical range of both modules is the same, the only big difference is the missing LoRAWAN certification for the RFM95W.


Here a more detailed picture of the Node with headers, SMA antenna connector and the JST battery connector to power the board (the power cable is not included).


TvB LoRaWAN Node with accessories

To make my applications more “Plug & Play” I made myself a great gadget: The “Proto Shield”.
It’s designed to fit on the node to create prototyping space.
It even has an extra mosfet load-switch circuit with LED indication to power ON/OFF external circuits! Great, isn’t it?


TvB Proto Shield with female headers

Want to know more? Get in touch here

Please note: This hardware is not for sale, neither is the schematic or design files.
The developed hardware / software is not open source.

LoRaWAN Node Shields

My new LoRaWAN node also comes with additional shields to realize the most crazy projects. They are available for order with the any version of the node.

All shields are the same size as the node and are connected with two regular 14 pin headers.
At the moment I developed 3 shields:

  • Proto shield
    • Proto area
    • Load switching mosfet circuit controlled by digital pin to power on/off external electronics. With power-on LED.

TvB LoRaWAN Proto Shield Rev.2 - Preview

  • RTC shield
    • DS3231 with 3V backup battery.
      The DS3231 also has a programmable interrupt output to wake up the LoRaWAN node every X seconds, minutes, hours, …
    • Small proto area
    • Load switching mosfet circuit controlled by digital pin to power on/off external electronics. With power-on LED.

TvB LoRaWAN Node RTC Shield Rev.1 - Preview

  • RTC & GPS shield
    • DS3231 with battery backup
    • Ultra small GPS module (OriginGPS Nano/Micro Hornet) with onboard, buildin GPS/GLONASS antenna
    • Small proto area
    • Load switching mosfet circuit controlled by digital pin to power on/off external electronics

TvB LoRaWAN Node RTC + GPS Shield Rev.1 - Preview

The RTC/GPS node is only available without GPS module

The new LoRaWAN Node is alive!


Last week I found some time to assemble and test my new LoRaWAN Node and here’s the result.

TvB LoRaWAN Node - Front viewFeatures of the new board:

  • Only 25 mm x 40 mm!
  • Low power Atmega1284p microcontroller (Arduino compatible, incl. bootloader & library)
  • Standard JST battery connector
  • Onboard single cell li-ion / polymer battery charger with charge status LED (charging from USB programmer or solar panel)
  • Onboard 3.3V LDO regulator with protection circuit
  • Battery voltage measurement
  • Breadboard compatible headers
  • Reset button
  • RGB led
  • Extra blue led for RX/TX activity (default color, can be changed on request)
  • Full FTDI programming header
  • U.FL & SMA antenna connectors
  • LoRaWAN:
    • Support for Microchip RN2483 & RN2903 LoRaWAN modules
    • Support for HopeRF RFM9X LoRa modules

The best part of this module is that the LoRaWAN module can be chosen.
I’ve added support for both modules on the same board!
TvB LoRaWAN Node - Back view

This Node is a perfect starting base for most of my LoRaWAN projects. It’s the same size as the recent Sodaq LoRaONE and a whole lot cheaper! (But there’s no fancy GPS or accelerometer).

More details, info, .. can be found in this new post:




New “TvB LoRaWAN Node” in development

After the succes with the first versions of the “TvB Wireless Node’s” I decided to develop a new, upgraded LoRaWAN node.

This new node will support 2 different LoRaWAN modules:

  • Microchip RN2483 LoRaWAN module
  • HopeRF RFM9X LoRaWAN module

This means the node can be fitted with an RFM95 or an RN2483, whatever fits you best.

Here’s a sneak peek of the new node!

TvB LoRaWAN Node

The node is about te same size as the SODAQ LoRaONE and doesn’t have a build in GPS or accelerometer.
When comparing the price tag there’s a huge difference!. Most project’s don’t need fancy extra’s. They only need a compact, powerful and multi purpose LoRaWAN node. So here’s my solution that fits all my use cases.

Changes from the previous version:

  • Combined RFM9X and RN2483 design on back-side
  • Added voltage protection circuit
  • Added battery charger circuit with charging LED for lithium ion battery’s
  • Added a small RGB-led
  • Changed the programming header to a fully compatible 6-pin FTDI connector.

Check out the most recent blogposts

LoRaWAN IoT Node


Past few month’s I’ve been researching and testing with LoRaWAN networks.
After some good test results I decided to developed my own compact, fully Arduino compatible LoRaWAN Node and also develop use cases with them. When developing this hardware it was almost impossible to buy the RN2483 LoRaWAN modules from Microchip. That’s why I chose for RFM95W LoRa modules from HopeRF. Not a bad choice after all, the hardware is very impressive!

The “TvB Wireless Node”, not just another LoRaWAN node:

LoRaWAN Node


Bottom side


  • Atmega1284p with 128kb program memory, running on 8 MHz with Arduino bootloader
  • Supports all RFM95-98 LoRa tranceivers
  • Supports regular tranceivers of the RFM69 series. The RFM69-W, -HW and -HCW versions are compatible.
  • SMA + U.FL antenna connectors
  • Breadboard compatible header pins for easy prototyping
  • 3.3V onboard regulator
  • Red & blue onboard led
  • JST battery connector
  • Battery voltage measurement
  • Reset button
  • Programming header for (CP2102 or FTDI) USB to serial programmers

The microcontroller has more than enough program memory for the LMIC stack for LoRaWAN and other functions. Beside that this module can also be used as point-to-point communication with LoRa (without using an LoRaWAN network) or with regular 433/868/915 MHz transceivers (RFM69).

You get all these options on a tiny 41 x 23 mm board with both U.FL and SMA antenna connector options!

Bare PCB with Atmel1284p and resonantor

Oh wait, when I said “tiny”, just compare the node with the SODAQ Mbili development board for LoRaWAN. It’s just a little bigger than Microchip’s RN2483 LoRaWAN module.

SODAQ Mbili vs. TvB Wireless Node Rev. 3

Easy prototyping

A LoRaWAN node is nothing without easy prototyping options. This one is breadboard and prototype PCB compatible! All main data lines are available with enough digital I/O’s and ADC pins. All you need!

TvB Wireless Node - Proto PCB

Or just directly connect a battery for your mobile application. All types of battery’s can be used with a maximum input of 6V DC. The LDO voltage regulator guarantees a stable 3,3V power supply, even for voltages as low as 3,45V! This makes the use of single cell li-ion battery’s ideal without damaging the transceiver.

TvB Wireless Node - Battery

Use cases

Developing a small or portable LoRaWAN application? No problem for this hardware. Here are some examples where I used my LoRaWAN node for.

TvB Wireless Node - Window

Open door detector

TvB Wireless Node - Collecting sensor data

Battery powered outdoor data logger

TvB Wireless Node - Industrial IoT

Industrial LoRaWAN application with 230V power supply

TvB Wireless Node - Thermocouple and LCDMeasuring high temperatures with a thermocouple, displaying temperature on a LCD screen and transmitting over LoRaWAN

TvB Wireless Node - LoRaWAN GPS tracker

A portable GPS tracker, can also be used for measuring LoRaWAN coverage & range

Next project?

Connecting and digitalizing our beehives with LoRaWAN, and in the far future maybe tracking the flight path of our bees? 🙂

TvB Wireless Node - Beehive


Back to the technical side, this pinout diagram shows all features of the module.
TvB Wireless Node Rev.3 - Pinout

TvB Wireless Node Rev.3 - Legende


The Atmel microcontroller provides awesome support for Arduino. The Arduino bootloader on the microcontroller together with the custom board in Arduino IDE make it very easy to direct upload sketches into the node with just one click. This makes prototyping and developing a whole lot easier.

Chose board small

The custom board

Chose example small

Included example programs


Testing with my LoRaWAN GPS tracker revealed the range goes up to 18.6 km (default 1/2 wavelength antenne on the node). That’s a very impressive range!



Future upgrades?

  • Adding charging circuit for li-ion batteries
  • Adding voltage polarisation & overcurrent protection
  • Low power features

Affordable PoE? DIY

PoE (Power Over Ethernet) enabled switches costs a lot of money, so I decided to make my own. After some research i found out how PoE works, and it’s fairly easy to modify an existing Fast Ethernet 10/100 Mbit/s switch.

Here is how Ethernet cable / UTP cable is wired:

PoE 802.3 af

PoE is based on the 2 wire pairs who are not used in 10/100 Mbit/s networks, 1 pair + 48V DC and 1 pair Ground. ( 1 pair = 2 wires)

My modification to the switch is similar to “Passive PoE” injectors. it’s based on “PoE 802.3 af” and it injects 48V DC but without the auto sense protocol to check if the connected device is PoE capable. This can cause permanent damage if you plug in other devices in the modified switch who are not PoE capable. In other words, it’s a dumb PoE switch.

Note: Do not try this with Gigabit switches because these use all 4 data pairs instead of only 2 pairs for 10/100 networks!
Note: Use only straight cables, no cross over cables. These can damage the connected device.

All components i needed for this mod:

– 10/100 Mbit/s switch (5 port switch i had laying around)
– electronics wire 0,2 mm²
– External 48V DC power supply
– Fuse holder with fuse (20 mm glas fuse, 0.75 A)
– 5.5mm/2.1mm DC plug
– LED with resistor (power ON indicator)
– Diode 1N4007 (polarity safety)
– Glue gun & glue sticks

Here is the result of  the switch:

PoE Switch

On the back the 48V DC input with green power ON led:

PoE Switch

The connections to the Ethernet cables:

PoE Switch

The + 48 VDC is connected to pins 4 & 5 and ground (-) to pins 7 & 8 of the 4 outgoing PoE ports, the incoming LAN port is unmodified. The 20 mm glass fuse is a regular blow 0.75 A. Just in case something goes wrong.

All switches have resistors connected to ground on unused wires to avoid interference, in my case each unused wire was connected with a 75Ω resistor to ground. If these resistors are not removed, the 48V input would flow through the resistor to ground. And there are 8 resistors in total for 4 ethernet ports.

Not a good idea to leave those resistors there, 1 resistor will have a current of 48V/75Ω = 0,64 A !

This is how to prevent this: just break the PCB traces!





I use this switch to power PoE capable IP camera’s (CCTV) with solid 100% bare copper UTP cable.

Note: Do not use CCA (Copper Clad Aluminum) UTP cables, these are not suitable for conducting currents (too high resistance) and can cause high power loss in the cables. Remember why they removed all aluminium conductors from residents?? Because the cables were overheating and causing fire.

Upgraded version of the Arduino Roller Shutters / Roller Blinds Controller

It took a while to get all the components for the final version, found a little free time to etch the PCB, solder everything together, test the final version and shoot some pictures but it’s worth the result!

(Note: the on screen display language is Dutch)

2015-04-16 11.50.25

Final result of the controller

The controller is a mobile battery powered device, it can be placed everywhere! No longer dependent from power-consuming power adapters!!!!!

Battery value is measured automatic and gives an indication when to recharge the controller. The operating periode is about 2 to 3 weeks with two re-used 6 years old lithium ion 18650 batteries from an old laptop battery pack. The remaining capacity is not much but good enough for this application.

The OLED display consumes the most power. OLED stands for organic LED, this means the display continuously emits light and is easy to read in the dark. The “most” power is a couple of mA’s but this is a lot against some other LCD displays (some µA’s).

The Arduino runs on a 8Mhz clock, with the necessary power saving functions it runs on a couple of hundreds µA (Note: the red power led on the Arduino Pro Mini is removed!), with the OLED display (and all the remaining electronics are negligible) it’s only mA’s of power consumption in total.
That’s battery friendly i guess 🙂

The overall operating voltage has to be between 2,7V and 5,5V for correct functionality. (battery protection auto. shutdown voltage at 2,5V)

Some features of the controller:

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Time schedule of 5 shutters (open/close)

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Option to choose between stored time or light sensor based (with adjust value: lighter/darker) closing of the rolling shutters

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Example: setting and storing time open/close for Rolling Shutter 1

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Setting and storing the day, month and year

The controller has a menu to adjust, change and store:

time (hours: 0 to 23, minutes: 0 to 59)
day (1 to 31)
month (1 to 12)
year (2015 to 2099)
day of the week (Monday, Tuesday, Wednesday, and so on)
random range in minutes (when time is set to 8:00 and random range is 10 minutes: the shutters will open between 7:55 and 8:05)
light measurement adjustment (threshold “dark” value for light sensor)
all roller shutters have there own open/close hour (accuracy is 1 minute, for instance 8:16)
enable/disable channels (for instance if you have a door, you can disable that channel so you can still re-enter. That would not be possible if the shutter was closed!!!)
automatic/timed shutter closing (the option can be “Time” of “Light”, Time means stored time and Light means sensor based)

Note: the time, day, year, .. are kept by the DS3231 Real Time Clock IC and when powerless, powered by the 3V coin cell (= memory function)
Note: other parameters are stored permanently in the Arduino’s EEPROM

The printed circuit board in detail:

The PCB is made in 2 stackable boards, the bottom module is the Arduino Pro Mini 3,3V controller with a LiPo Fuel Gauge from Sparkfun, Lithium ion battery charger module with battery protection for charging and discharging (with shutdown when the voltage drops below 2,5V for no battery damage), a ON/OFF master slide switch, reset button and battery connector terminal.

To recharge the module, simply plug in a micro USB cable. The charger board has 2 on board indication leds: RED: charging and BLUE: charged.

2015-04-16 11.44.12

Bottom module

The top module has al the features for time keeping (DS3231 IC in the middle of the board), light measurement, switching capabilities, 5 input tactile push buttons for navigation in menu & settings and the OLED connector for the 1,3″ OLED display. At the top of the module is the connector for the Niko Easywave remote control.

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Top module (picture without OLED display)

Side view
The side view of the controller, the headers are default 2,54mm headers. The male headers are 17mm long in stead of the 10mm usual. (because the 3V coin cell backup battery for the RTC on the bottom of the top module)

2015-04-16 11.41.30 Side view of the controller

2015-04-16 11.43.46

 Bottom side of top & bottom module (with 3V coin cell on the left board)

Following pictures are the bare PCB’s

2015-03-18 13.39.192015-03-18 13.39.41

That’s a short overview of the controller, more detailed information about the working and components can be found in the previous post of the “prototype” of the controller.


Arduino Roller Shutters / Roller Blinds Controller

The Arduino Roller Shutters Controller is an Arduino Pro Mini 3.3V based device to automate the roller shutters / roller blinds.

My current setup for the control of the roller shutters / roller blinds is a Niko Easywave system with multi channel 868,3 MHz remote control and built-in wall receivers. This remote controller has only buttons and no possibility to set a time for automated functions.
Unfortunate in the Niko Easywave series there is no affordable alternative for automatisation so I decided to make my own custom Arduino home automation system. Here is an overview of my controller:

Niko Easywave Prototype Final

The home made controller

Pro Mini

Arduino Pro Mini used for the controller

Rolling shuttersRolling shutters (picture only for demo)

Niko materials: 
Niko Easywave build-in receiver for shutter control: product 05-333
Niko Easywave remote controller with 4 channels and 13 buttons: product 05-312

Niko 05-333 Receiver     Niko 05-312 Remote    2015-02-26 13.32.43 aangepast

For more information about the Niko products:

The research, 868.3 MHz is a no-go:
The radio frequency is 868.3 MHz, not a very often-used  radio frequency.
The best solution would be to generate codes on this frequency in combination with a transmitter for the Arduino. But I was unable to successfully copy the transmitted codes or generate compatible codes. The receivers are self-learning so I also tried to learn them my codes but this didn’t work ether. So the used protocol stays a mystery.

Arduino “push a button”:
After that I decided to design a circuit so the Arduino can “push a button” on the remote.

With a direct digital output/input from the Arduino you can bypass a real switch, witch in reality equals a “push” on a button. In my case iI wanted to keep the 2 systems completely separate. In this way I can’t damage the original remote with any external voltages.

After some measurements and research on the PCB of the remote I connected wires directly to the buttons and brought them out with a pin female header connector so I can easily disconnect the remote when necessary.

The “push” circuit is very simple and based on optocouplers I had laying around, the circuits are separated with an optical coupling. An optocoupler is a LED and photodiode in the same package. When current flows through the LED, the resistance of the photodiode decreases. This means no VCC of GND signal is connected. This also means the original battery has to remain in the remote to power itself.

Optocoupler diagram

Outputs required for controlling the remote:
On the remote there are in total 12 buttons who need to be “pushed”, so 12 optocouplers and 12 digital outputs are required. On a regular Arduino Pro Mini 3.3V there are not a lot pins. Well, this may be a problem considering what’s used in this project:
The Atmel ATmega328P has only 32 pins with 22 I/O pins configurable.
In reality these are not all digital outputs, some are analog input only like pin A6 & A7 and cannot be used as output.
Pin D0 & D1 are the TXO en TXI programming lines and should be left alone if possible.
Finally there are the data lines: I2C (A4 & A5) [Needed for RTC] and SPI (D9, D10, D11 and D12 mostly) [Needed for OLED display]

This means I have 12 outputs and 2 analog inputs left for general purpose.
Good luck I only needed 12 outputs! These were all used for controlling the remote.

This also means I have 2 analog inputs left at the moment.

Time keeping made easy:
A feature of the controller is the function to keep track of the current time without loosing it when powered down. To solve this I used a RTC (Real Time Clock) DS3231 module. This module does al the time keeping including date and year. All I need to do is process and manage the time. When the module starts up it reads the current time stored in the module, from that moment the Arduino works interrupt based by counting the hour, minutes and seconds passed. To keep the time correct the Arduino synchronizes once a day with the RTC to get the exact time because the time shifts a couple of seconds a day.
The module is connected on the I2C data line (SDA/SCL) and has a 3V cell as backup voltage to remember the real time.

DS3231 RTC

The DS3231 Module

A small OLED display:
A standalone device without any way to display information is not very handy. That’s the reason i chose to add a small 1.3″ SPI OLED graphics display. The display has 128×64 pixels and can be used for graphics, not only text. It uses SPI to communicate with the Arduino on 4 general-purpose  I/O pins. I chose the default software SPI pins: 9 (MOSI), 10 (CLK), 11 (DC), 12 (CS).

Niko Easywave Prototype Screen

What about controls for the display?
Because I only have 2 analog inputs left and I need more than 2 buttons to use the controller I was forced to use a resistor network in combination with tactile switches to detect any inputs. I chose for 5 tactile switches, this is the most users friendly for this application.
The buttons are read by ADC (Analog to Digital conversion) and processed in the Arduino to decide which button was pushed.

Tact Switch

Extra feature: Photodiode for light measurement!
After a while I came up with the idea of using a photodiode to measure the light intensity. This “sensor” looks like a ordinary 5mm LED (located next to the OLED display), is also read by ADC and is connected to the very last available pin on my Arduino Pro Mini 3.3V. The Arduino processes the value and now can be used for an automatic light intensity closing.

A short specs overview:
– Arduino Pro Mini 3.3V (8MHz)
– 1.3″ SPI OLED display (128×64 pixels)
– RTC DS3231 Module
– 5 inputs switches
– 12 outputs
– 12 optocouplers
– Photodiode

Total expenses:
Less than 15 euro everything together. This is really cheap compared to those expensive home automation controllers. Off course there are a lot of hours researching, developing and testing witch you don’t have when you buy a system.

The big advantage of building your own controller is that I can do anything I want, that’s not possible with bought stuff.

And this is the result:
The device is still a prototype and made on pieces of stacked breadboard. In the future the device is getting it’s own PCB with Lithium-ion battery power supply. That’s off course the main reason the 3.3V Arduino Pro Mini was used.

Niko Easywave Prototype Final Arduino Pro Mini 3.3V (8Mhz), RTC module DS 3231 and OLED display with 5 buttons. 

Niko Easywave Prototype Final

Remote connected to the controller

 And this is how the remote is modified inside:

Niko Easywave Remote inside

Power consumption:

At the moment the controller can operate between maximum 5.5V and will still work to a minimum of 2.8V to 2.7V. This is ideal to use with a Lithium-ion battery.
On 5V the measured current is 15-20 mA
On 3V the measured current is 10-12 mA

For example, on a single 18650 3,7V Lithium-ion 2600 mAh cell the controller should work between 5 and 10 days in theory.

Note: with a optimized Arduino code you can get even better battery life. (I did nothing in the Arduino code to save any power)

I’m not planning to post the code. But questions are welcome.

Prototype in action!
Video coming later!

Filmpje varen Smit Nederland

Ik heb onlangs een filmpje gemaakt van de Smit Nederland tijdens het varen.
Het filmpje is gemaakt bij Zwembad Aardenburg.

In het filmpje is te zien hoe het vaargedrag van deze sleepboot is.
Heel wendbaar dus!

Op de achtergrond zijn nog een aantal andere boten te zien, onder andere een groot oorlogsschip.

Mvg, Thomas… nog meer updates binnenkort!

DIY 4 Channel Stereo Mixer (Mengpaneel)

De schema’s zijn eindelijk rond,
Ik heb een schema getekend voor een mengpaneel met 4 Stereo kanalen. (A, B, C en D).
Eindelijk lijkt het project goed haalbaar, vandaar dat er extra functies voorzien zijn.


– 4 kanalen Stereo line-in (A, B, C en D)
– Elk kanaal heeft zijn eigen Hi, Mid en Low Tone regeling.
– Balance regeling per kanaal.
– CUE functie voor A en B (met hoofdtelefoon aansluiting voor pre-mix luisteren)
– Crossfader voor A en B om te mixen
– Kanaal C en D zijn extra, ze kunnen aan en uit gezet worden met een knop.
– Stereo VU meter op de uitgang (2x 10 leds BAR)
– “Main level” (met 2 faders aan de uitgang)
– CUE volume instelbaar
– …

Dit is een voorbeeld van het eindresltaat:

Mixer layout

Mixer layout

Nieuwe foto’s i.v.m. GIP

Ik heb nog een aantal foto’s toegevoegd aan het album “Foto gallery”
Het zijn foto’s van de nieuwe  prototype module en detail foto’s van de GIP robot.

Klik hier om naar de Foto gallery te gaan

PIC bordje V1.1:

PIC bordje v1.1 foto 1

PIC bordje v1.1 foto 1 (bovenaanzicht)

PIC bordje v1.1 foto 2

PIC bordje v1.1 foto 2 (vooraanzicht)

PIC bordje v1.1 foto 3

PIC bordje v1.1 foto 3 (zijaanzicht)

PIC bordje v1.1 foto 4

PIC bordje v1.1 foto 4 (aanzicht zonder LCD scherm)

PIC bordje v1.1 foto 5

PIC bordje v1.1 foto 5 (aanzicht zonder LCD scherm)

PIC bordje v1.1 foto 6

PIC bordje v1.1 foto 6

Detail foto’s van de GIP robot:

Robot hardware foto 1

Robot hardware foto 1 (Dwengo PIC KIT 2 Programmer)

Robot hardware foto 2

Robot hardware foto 2 (achterkant)

Robot hardware foto 3

Robot hardware foto 3 (zijaanzicht)

Robot hardware foto 4

Robot hardware foto 4 (hardware close up)

Robot hardware foto 5

Robot hardware foto 5 (achterkant hardware)

Robot hardware foto 6

Robot hardware foto 6 (LCD scherm met achtergrondverlichting)

Robot hardware foto 7

Robot hardware foto 7 (montage voorbumper)

Robot hardware foto 8

Robot hardware foto 8 (achteraanzicht voorbumper)

Robot hardware foto 9

Robot hardware foto 9 (voorbumper met sensoren)

Robot hardware foto 10

Robot hardware foto 10 (zijaanzicht, USB Bootloader aangesloten)

By Thomas vB Posted in GIP

DIY Mengpaneel

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Op mijn planning stond dat ik een klein mengpaneeltje wil maken voor audio, na enige verdieping is dit ‘kleine’ mengpaneel veranderd in een professionele zelfgemaakte DJ mixer met uitgebreide functies van hoge kwaliteit.

Hier zijn een aantal voorlopige specificaties:

– Minimaal 3 Stereo mix kanalen (+ andere functies, staan nog niet allemaal in een schema)
– Tone control (Hi, Mid, Low) per mixkanaal
– Volume per mixkanaal regelbaar
– Balance per mixkanaal regelbaar
– Crossfader tussen A en B
– Stereo out master volume met VU meters
– Headphone out (cue functie)

Andere voorziene aansluitingen zijn:

– 3x Line in Stereo
– Mic input (optioneel)
– Mini-jack Stereo input (handig voor kleine toestellen zoals MP3 enz.)


Dus dit is niet zomaar een kleine mixer, er komt veel passive en active elektronica bij kijken. De kostprijs zal onderdrukt blijven omdat alles zelfbouw is. Het resultaat zal een gepersonaliseerd mengpaneel zijn van hoge kwaliteit.

Preview van hoe het zou moeten zijn (toch zo is het in het echt)
Zo’n resultaat zou perfect zijn, we gaan proberen!

Preview Mixer

Preview Mixer

Smit Nederland

Mijn deeltijdse hobby is ook modelbouw, ik ben graag bezig met elektronica. Daarom heb ik in mijn RC Boot zelf mijn elektronica ontworpen en gemaakt.

Een aantal modules die ingebouwd zijn in de Smit Nederland zijn:
– Digitale snelheidsregelaars (met PIC microcontroller, zelflerende nulpunt en maximum snelheid en achteruit)
– 2 kanaals schakeldecoder met vermogenrelais (met PIC microcontroller, met- en zonder geheugen functie)
– 12 kanaals Encoder en Decoder (met PIC microcontroller, multiplexer voor 1 kanaal 12 functies,  met- en zonder geheugen functie)
– Dieselgeluidgenerator (met instelbaar geluid en snelheid gestuurd)
– 12V naar 5V voeding, geen batterijen nodig voor de ontvanger

Voor de rest heeft de boot ook nog verlichting, boegschroef, sleeplier, ankers,..

De motoren zijn 2x 12V Decaperms. De batterij is een 12V loodaccu van 7Ah.


Hieronder enkele foto’s van de boot, Smit Nederland:

Smit Nederland 1

Smit Nederland 1

Smit Nederland 2

Smit Nederland 2

Smit Nederland 3

Smit Nederland achterdek

Smit Nederland 4

Smit Nederland sleeplier , verlichting, achterdek


Hier zijn enkele printplaten te zien, de zelfgemaakte elektronica van de boot:

PIC Snelheidsregelaar

RC PIC Snelheidsregelaar

RC 2 kanaals decoder

RC 2 kanaals decoder

Afronding van de GIP

Vanaf nu is het GIP Dossier ook hier online in digitale vorm te openen en te downloaden. Het Dossier is een volledige beschrijving van het eindwerk (GIP).

Het GIP Dossier is hier te openen in een PDF bestand. Het Dossier is ook te downloaden hier voor als de link niet meer werkt.

Het besturingsprogramma voor de Robot is hier te downloaden (, .zip)

Hier volgt nog een extra filmpje van het resultaat van de Bluetooth Robot:

Als er vragen of opmerkingen zijn kan er altijd gereageerd worden op elke blogpost.

By Thomas vB Posted in GIP

BlueBot Robot Besturingsprogramma voor Windows

Alvast een voorproefje van het geheel, hier is het besturingsprogramma van de Robot te downloaden. Het is een volledig vrijstaand computerprogramma om de Robot met te besturen.

Het heeft enkel een Bluetooth verbinding nodig met de Robot.


BlueBot Robot Besturingsprogramma (windows installer)

Het GIP Dossier met gebruikershandleiding




Opstartscherm van het programma

By Thomas vB Posted in GIP

Filmpje van de robot in werking

In de loop van deze week heb ik de beide printplaten voor de bumper modules gemaakt en gemonteerd op de robot. Ik heb er een filmpje van gemaakt met de robot in werking met de bumpers erop gemonteerd. In het filmpje bestuur ik de robot met de computer en schakel ik de verlichting ook aan en uit op afstand met de computer via de Bluetooth verbinding met de robot.

Het eerste filmpje van de robot:

Het tweede filmpje van de robot in het donker:

By Thomas vB Posted in GIP

Microcontroller module PIC18F4550 met LCD scherm

Ik heb de module die ik eerder gebruikt heb op het prototype van de Robot aangepast zodat er een LCD scherm op past. Op vraag van de leerkracht en naar de toekomstige jaren toe zullen we dit bordje gaan gebruiken in de lessen. Het is volledig universeel en daarom ideaal voor de leerlingen. De functies zijn volledig dezelfde als het bordje van begin dit schooljaar, enkel is het LCD scherm toegevoegd om het gemakkelijker te maken om te gebruiken. De modules vervangen de ‘Dwengo’ bordjes op school en zijn goedkoop te maken en daarom ideaal voor de leerlingen.

Verder ligt dit bordje ideaal in de hand en is het zeer compact, volledig van functionaliteit en zeer gebruiksvriendelijk.

Microcontroller module met LCD scherm

Microcontroller module met LCD scherm 2

By Thomas vB Posted in GIP

Bumper modules voor de Robot

Ik heb deze week de Bumper modules afgewerkt. De bumpers zijn de voorbumper en de achterbumper van de robot.

Hierop zitten de schakelaars voor de noodstop en een aantal Leds. De Leds hebben functies zoals de dimlichten; voorlichten en achterlichten, grootlichten en pinkers van een echte auto. Onderaan de voorbumper is een extra sensormodule voordien met 4 optische sensoren die kleuren kunnen detecteren. Hiermee kan onderscheid gemaakt worden tussen wit, zwart en alle andere kleuren. Ook is deze module capabel om de rand van een tafel te detecteren zodat de robot niet van een tafel kan rijden.

Gefreesde bumpers:

Gefreesde printplaat voor-en achterbumper

De voorbumper:

Afgewerkte printplaat voorbumper


Afgewerkte printplaat achterbumper

By Thomas vB Posted in GIP

Hoofdmodule Bleutooth Robot

In deze post ga ik het kort hebben over de Hoofdmodule van de volledige robot.

Op deze module zitten alle functies in 1 module, dit wil zeggen dat deze module alle onderdelen bevat die nodig zijn voor de volledige robot. Op deze module zit een LCD scherm, motor sturing, LED sturing, 5V regelaar, USB, programmer en nog andere functies die de robot slim maken zoals een lichtmeting en spanningsmetingen voor de interne batterijen. Op deze module kan een een batterij aangesloten worden, als de externe adapter verwijderd is zal de robot direct overschakelen op de batterijen. Zonder onderbreking en spanningsverlies. Er zijn 2 schakelaars voorzien; één schakelaar voor de robot aan en uit te zetten en één voor de keuze van de spanning voor de motoren.

De module is voorzien met de nodige aansluitingen voor bumpers, waarop led’s, schakelaars voor mechanische beveiliging en optische sensoren komen om kleurverschillen op de grond te kunnen volgen.

Hoofdmodule met programmer, USB en voeding aangesloten

 Deze module is getest en werkt. Later komen de beide bumpers en de sensormodule (module waarop de optische sensoren gemonteerd zijn die vlak boven de grond aan de onderkant van de voorste module geplaatst worden)

By Thomas vB Posted in GIP