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Connection between smarthone and chessboard

Hello Certabo friends,

i have some difficulties and hope you can help me. The connection between the board and my iMac under macOS works fine.

Now i desperately try to connect my board to a smartphone without the rasperry pi unit.

As far as i understand i cannot connect my iphone or ipad directly to the board because the ios devices can only function as a remote display for the rasperry pi computer.

But i have read that you can connect an android device direct to the board and use it with the „certabodroid„ or the “chess for android“ app without the need of the Raspberry pi computer.  I tried that with two older android phones laying around here (galaxy a3 and an unknown lg device) but i doesnt work. Both apps do not find the board or a usb connection.

Can  anyone pls give me a hint where the problem might be? Are the phones to old or do i need special devices that are more powerful to supply the board with the necessary power?

Thanks in advance

Hello Homki

Yes you can connect. You need an OTG adapter i assume you have.

I'm not sure if you are using a magnetic plug or not on chessboard. But just to be sure check the following :

If you have standard plug micro-usb cable, when you plug the usb cable in the OTG adapter you will possibly end-up with two micro-usb  ends. If this is the case be sure the micro usb end of OTG cable goes in the phone and the other in the board as it is unidirectional. If you have a magnetic plug or Usb-C on your phone there is no possibility to get it other way round.

After this, please check when you plug, if all the leds turn on if yes this means that the phone can supply the board and therefore shall connect too.  Most of the Android phones and almost 100% of tablet has enough power to supply as it's standard USB device but we cannot exclude some old phones are somehow limited in this by phone hardware.

After this you should be able to connect but the board is not connected automatically. For chess for Android you shall have long press on the screen below game area and it should appear connect to e-board select Certabo and then a pop should appear "connect sd......." click on that message and the board will be connected.

On Certabodroid swipe from left to get access to menu and select " Connect to Board" again a message shall appear. Start the game and you will also get a confirmation message that the board has been detected. You shall redo this in case you disconnect the board or leave the device going to sleep to restarst where you left.

Last possibility but i do not think this is you case, if you have another serial application like "Serial monitor" which will take over automatically the connection then the port will be kept busy by this application and so you should avoid this disabling the automatic connection by this. This is very specific possibility using very custom android app for technical purpouse so i really do not think it is your  case.

Hope this helps you out  let us know if you can work it out or need additional help

All the best




Dear Pietro,

thanks for your fast and detailed answer and in my case also for solving the problem. In fact i had the wrong OTG adapter, in my hardware combination it was only possible to connect the end of the OTG adapter into the board, not into the phone (I had a micro-usb adapter, but an usb-c phone). I didn't know that this adapter is unidirectional, thanks for explanation.

I bought a new adapter whose end i can connect to the phone and voila: it works perfect!!

Thank you so much.