RTK.GPIO Board

I was recently given the opportunity thanks to a good friend, to check out the RTK.GPIO board, a small PCB with microUSB socket which promises to emulate the IO of a Raspberry Pi.

The board, sure enough has a Raspberry Pi connector looking remarkably similar to the Pi with 3v3 and 5v outputs.  The Kickstarter project advertises “an easy way to be able to add a Raspberry Pi GPIO header to your desktop or laptop.

The project managed to gain pledges of over £10k  which is pretty amazing for a simple board with little more than a processor and interface chip.

Claiming correctly that the Raspberry Pi add-on market is huge, the project states that there is an add-on board or HAT for “almost every electronics project for the Raspberry Pi”.  That kind of sets expectations for the board, sadly, a little too high.

Headlines like that set the pulse racing – could we test almost everything Pi I/O related on a PC? Well, no. Read on and you see that the IO is “basic” –  and you can do basic I/O – i.e. flashing a few lights. Well, you can do that on the BBC Micro-Bit – a horrible little “educational” board which can also do very little (why they didn’t go for the ESP8266 and Arduino-compatible software is beyond me given the massive user bases and hence support).

The Kickstarter page compares this simple IO board to Arduino, Raspberry Pi Zero and BBC Micro-Bit  with large user-bases. An Arduino Chinese copy is supposed to be £8-10 (wrong, Nano boards are available at under £2 inc postage and immediately programmable – possibly a tad more with the connectors pre-soldered). I won’t go into the others – you get the point.

Near the bottom of the Kickstarter page is a link to the software.  At the bottom of THAT page is a link to the LATEST software – except that it isn’t – it’s a 404 page actually. The actual software page, despite being quite old now (2014) has some recent updates but is not entirely error-free.

There is a reference to stretch goals including I2c but it is left a little vague as to what happened there (given the age of the board you’d think this would be updated).

The software is in two halves, code for the actual board and Python for the PC. I was hoping for some I2c examples but as far as I could tell most of the examples were variations on the same thing – flashing a few lights on and off. One example goes a little further and programs up an LCD display (again simple I/O) which might be marginally entertaining but again is merely using simple I/O

Had this board featured i2c and other serial protocols, opening up possibilities to control a wide range of devices, then I could see it being worth having on the bench for beginners… but to flash a few lights, for me, a cheap Chinese Arduino beats this hands down with a decent IDE that is easy for beginners and opens up a whole world of possibilities long after your first flashing light– whether you are using Linux (including Raspberry Pi) or a PC. For £1.15 or slightly more for the soldered version and the free Arduino IDE you get WAY more for beginners and advanced programmers alike.

Some time ago I was after extending an ESP8266 and looked at various ways to do this – one of which was simply to turn an Arduino into an I2c slave to control  ports – input and output along with analog input and PWM out. I wasn’t at the time thinking of an educational tool but the code therein was simple and would take very little time to convert the code to running off the serial port of virtually any PC, making it even easier to use.

If anyone wants to run with that and turn it into an “educational tool” – by all means.

If it is Raspberry Pi you’re after, well the Pi Zero WIFI is around the same price as the RTK.GPIO, it easy to use with the vast number of example programs out there and with WIFI built in is way more powerful.