Oh, and I can even power the Pi from the PC PSU, if that PSU supports the charge from USB port even if PC is technically off, almost every PSU now has this feature in some manner of course. This project also lets a typical PC mainboard have a Ethernet WOL or magic packet (sort of) start feature given the Pi is always on. The various microcontrollers could all do this in some fashion, including using a Pi Zero. Again this another cool feature of the expensive PC and Server mainboards the Service Processor feature set.Īt some point I may even do a KickStart project for this, given there are no inexpensive devices to do this for a typical PC mainboard. Last, I will be setting up a temperature sensor to Pi, to measure the internal PC case temperature (not perfect but ok, to turn off the PC if needed). Moreover, I also wanted to see remotely, the PC case power LED and disk LED status, something just about every PC case provides, and Service Processors report the same via various methods. Only few very expensive PC (desktop) mainboards and most Server mainboards have these basic features, like HP iLO, Dell iRAC, or IBM iMM/aMM for example. This give me basic PC start/shutdown anywhere I have internet access or network access. This project is actually the next generation of a project I did a few years ago, that is in the Pi forums here, where I use a Pi as a Service Processor, meaning the Pi is online all the time, but the PC it is connected to is not, so the Pi can short the power switch on the mainboard via a relay (which is isolated of course) and same for the PC reset switch as well. It is a bit overkill, given the split and the 1st lead going to the PC case Blue LED, as current sink of course, but so be it. Even with the above said, I believe I will put some type of protection, between 2nd lead from the 6v source and INT1. During testing I was careful to avoid any spiking, but as you all note, what can happen often does, hence the isolation. I am lucky the blue diode in the case does not consume more of the current. The v6 source is actually an LED lead (to a blue diode) from a PC main board, which already split, 1st lead goes to the PC case, the 2nd line is connected to INT1, I have tested this with a voltmeter and the maximum voltage from the PC mainboard is between 5v to 6v, after the split, of course less, but the case LED still illuminates sufficiently, thus sinking sufficient mAs I think to avoid any issues. The odd thing is, if this can't be done this way, I can't seem to find any optoisolated break boards that are explicitly designed to work for inputs, all seem to be geared for output.Įveryone, thanks for the input, replies. I also think I could put a 5v to 3.3v step down module on the 6v source that would add some protection as well, but that module would likely take a hit if the 6v side spikes for some reason. When the 6v is present the GPIO input should read lowĭo I have this right? The only issue I can see if that if I get a spike from the 6v source side, I might burn the LED out, right? But at least the Pi input would be ok, since the maximum voltage is 3.3v via HV pin on the D213T board. When the 6v is not present, the GPIO input should read high I have a small D213 Opto-isolator board (ILD213T IC), like the link below,īut I am not sure I can use it the way I intended? All the examples I have found refrence this board for an output scenario, where GPIO pin is set for output connected to INT1 to drive signal to higher voltage scenario the OUT1 side.īut reading about isolators, they should work for input as well no? I want to protect the Raspberry Pi GPIO input via this board, and so I believe I can do the following.Ĭonnect 6v source power to board INT1 this would be the the anode for LEDĬonnect 6v source GND to board GND, this would be the cathode for the LEDĬonnect GPIO input to OUT 1, and enable GPIO pin pull up resister
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