Why get an expensive Pi when I have an old phone?

Re:Why get an expensive Pi when I have an old phone? by randomblock1 on Saturday November 14, 2026 @04:54AM (#50495625)

Phones are pretty robust though, meant to handle everyday use and abuse. In terms of failure, the battery is really the only thing to be concerned about. Most phones have some battery limiting option, and bypass the battery when the charger is connected. And if you're determined enough you can run without a battery.

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Re:Why get an expensive Pi when I have an old phone? by cowlevel on Saturday November 14, 2026 @05:09AM (#50495695)

Just plug all the battery slots in parallel to a 4.1V power source (that's a nearly full battery voltage). You probably have to solder them to make a reliable connection.

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Re:Why get an expensive Pi when I have an old phone? by randomblock1 on Saturday November 14, 2026 @05:25AM (#50495806)

I'm pretty sure the third/fourth pins are used for communication to the battery. I doubt the phone would be happy it wasn't responding. I vaguely remember some phones can just use a resistor for that pin? Either way it's not quite that simple.

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Re:Why get an expensive Pi when I have an old phone? by cowlevel on Saturday November 14, 2026 @06:51AM (#50496271)

Maybe. Try it and see. If it doesn't work it's probably just a temperature sensor (thermistor) and a resistor indeed simulates a certain temperature the same way your power supply simulates a charge state.

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