1 of 1 people found this helpful
Thanks for reaching out!
Because of the requirements of your project, a software approach will not suffice and you'll have to adapt a hardware approach. However, thanks to the Mini Breakout Board schematics being available (http://www.intel.com/content/www/us/en/support/boards-and-kits/000005699.html), much design won't be necessary.
I'd like you to check sheet 7 where the power button is located. As you can see it is a simple switch that when it is closed it makes the shorter path to ground changing the state from high to low in the signal GPI_PWRBTN_N. What this means is that the signal GPI_PWRBTN_N is active on low.
So, what we'd like to achieve is to change this configuration to something that makes the same effect but when the power supply is connected. My plan is pretty simple and you'll require these components:
1. An optocoupler or a relay.
2. A timer, a 555 will suffice.
3. A few resistances and capacitors to configure the 555.
As you may know the power button must be pressed ~8 seconds to turn on/off the Edison. So, what I'd like to do is to change the mechanical movement created by your finger to an electronic signal.
I plan to use the 555 as a Monostable Multivibrator. These circuits have only one stable state (hence their name: “Mono”), and produce a single output pulse when it is triggered externally. Monostable Multivibrators only return back to their first original and stable state after a period of time determined by the time constant of the RC coupled circuit. Taken from http://www.electronics-tutorials.ws/waveforms/monostable.html.
You can check this guide to configure the 555 as a Monostable Multivibrator: http://www.electronics-tutorials.ws/waveforms/555_timer.html. The trigger signal of the multivibrator for our configuration will be the charger, the multivibrator will not be triggered more than once as the charger will send a single signal and it will stay up. So, this should work perfectly.
So, now we have a way to get a signal for as long as we need (~8s) but we need a way to close the circuit because as I mentioned above, the signal GPI_PWRBTN_N is active on low.
This is where the optocoupler or the relay will be useful. You will simply use the 555 to activate the optocoupler or the relay and they will close the circuit instead of the power button. You are probably asking which one should you use, right? Then this depends on how you'd like to design your circuit, so I suggest you to check the following links and decide which one to use. The optocoupler is slightly more complex but it is still pretty simple but I must point out that this would be my choice, nevertheless, the relay should work just fine.
I hope this helps.
Thank you very much for this detailed explanation.
But I'm little concerned whether to attempt this modifications in the mini-brekout board or not, due to its extremely small size.
As if now, I decided to go ahead without a battery in the device and the issue will not occur.
Thanks & Regards
I understand, thank you for letting us know. Please keep us updated on your project and if you ever have any other doubts, please don't hesitate to come back to the community and we will try to help you in any way we can.