RTK GPIO BoardI 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.


3 thoughts on “RTK.GPIO Board

  1. Some valid points made about guides. I'm continuing to work on more guides throughout. I do agree with some parts needing more information.

    Once a kickstarter completes you can't update the main body of the text there as its a save of what was used for that. From what I can see I have no way of updating it. The many updates recently done say to visit the https://Rtkgpio.xyz website for information of which a lot of the missing software and manuals are updated.

    The point about arduino's being £2 is valid however I was comparing to Unos as they're more of a comparison. At the time the Microbit wasn't available to purchase. A Zero W is a little more expensive as you need to budget in the SD card 😉 I've also got to make a bit of money because I'm not a charity 🙂

    The comment about not using the ESP system I'm not sure about. For this it would have increased the cost. However I'd say the community is also quite large for the MBED system as it has arm's backing.

    It really was only marketed as a GPIO board. (General Purpose Input Output) and on the Raspberry Pi SPI, I2C & UART are alternative functions. I2C is at a reasonable state with work being still done on it.

    I've already fixed a couple of issues such as the wrong links and without being told I didn't know they were broken.

  2. Yeah with a ch340g as usb-serial converter, you won´t go very far in terms of speed.

    If you want something more serious, I recommend you to look at sysfs support for some USB converters, I found some with 12 GPIOs (pl2303tb, CYUSBS234).


    There is also a patch to the ftdi driver to change RX TX and more as GPIOs:


    The cheap ch341 breakout board I am playing with at the moment has 8 GPIOs, but you have to send some libusb packets to toggle them, a friend might work on a sysfs driver soon.

    Now since Linux 4.8, there is a new GPIO driver as /dev/gpiomem something with a tool lsgpio, but I have not tried it yet. It should offer the same speed as the hacked gpio driver shipped with raspbian, which the python library Rpi.GPIO is using.

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