What to do with mainboards removed from phones ?

[bcnaz]

I am about to remove the original mainboard from my Brave Heart phone and replace it with the newer 1.2b revised board.

The original is in perfect condition, it seems a shame to just discard it.

 I am wondering what to do with it.. ?  Perhaps an auto-dialer for a security system  ?

[User 18618]

The mainboard is a jury-rigged PINE A64 in essence... will it require a battery to function? Is it possible to connect a battery to the mainboard without the other parts?

[wibble]

We've got the schematics to check, including those for the board in the battery. IIRC the wifi and modem require a battery as that's where they get their power for the radio parts due to the high current they can demand. If you want to use a generic battery you'll probably have to supply an equivalent thermistor to prevent the charge controller going into safe mode - I assume it'll do that in case of a 'failed' temperature sensor. If the battery's significantly different you'll probably need to mess with the charge controller too - see Megous' writeup for some of the things to look at. All told it's probably easiest to get an equivalent battery. Having said that you also need to take care of the antennae, and I'm not sure how many of those use a normal connector - I think there's one for the modem as someone found the cause of their reception troubles was that it wasn't connected, but I don't know about the wifi/bluetooth or GPS. The lack of a USB connector is a bit limiting and the connector there is isn't too easy to deal with - and if you need to get the board and cable you may as well have bought a Pi Zero-W.

You could probably use it for something like a sensor hub (bunch of sensors on i2c via pogo pins and/or from BLE sensors, sending MQTT messages or storing to SD, perhaps with online analysis for data reduction?), an audio player, a clock with GPS time...or something.

[hiimtye]

I haven't tested it but wouldn't the USB-C connector be sufficient to power the device? you can test with your existing one and if it works order a spare one from the spare parts section on the pine store for the pine phone

[ThrillGates]

We've got the schematics to check, including those for the board in the battery. IIRC the wifi and modem require a battery as that's where they get their power for the radio parts due to the high current they can demand.

I haven't tested it but wouldn't the USB-C connector be sufficient to power the device? you can test with your existing one and if it works order a spare one from the spare parts section on the pine store for the pine phone

Just booted my phone without the battery and can confirm that neither the modem or wifi work.

To answer the original question, I think setting up a failover WAN connection for your home network could be a fun project.

[abcde]

I made a wiki page about this issue.

You could also see it as a SBC with LTE modem and UPS :)

We could make it so that the battery is also connected, so in the case of power issues, there will be a device to connect to.
Also, we could connect the power directly to the battery connectors.

https://wiki.pine64.org/wiki/User:Abcde/...rt_Recycle

[User 18618]

I made a wiki page about this issue.

Thanks for that!

I know Louis Rossmann soldered a couple of wires onto the positive and negative contacts - I guess that's one way of connecting the battery

[hiimtye]

I haven't looked at the schematics, but surely there should be some way of connecting the battery connection to the modem directly to power, i.e. using a zener and dropping resistor, or some other method

[LazLong]

I am about to remove the original mainboard from my Brave Heart phone and replace it with the newer 1.2b revised board.

The original is in perfect condition, it seems a shame to just discard it.

 I am wondering what to do with it.. ?  Perhaps an auto-dialer for a security system  ?

@bcnaz Thanks for this thread