[Mark B] had a problem. He’d come into possession of an Acer N30 PDA, sans batteries. He couldn’t just throw any old cells in, since the unit expected to communicate with an onboard controller chip in the original pack. What ensued was his effort to emulate the original battery controller hardware. This is classic Hackaday right here, folks.
Just wiring in typical Li-Ion voltages to the PDAs battery pins wasn’t enough to make this Windows CE device happy. The device kept fleeing to sleep mode, thinking the battery was faulty or very low. Eventually, inspecting the motherboard revealed the PDA hosted a BQ24025 charger IC from Texas Instruments. [Mark] surmised it was trying to communciate with a BQ26500 “gas gauge” IC from the original battery pack. Armed with that knowledge, he then set about programming an STM32 chip to emulate its behavior. He then successfully ported the functionality over to a CH32V003 microcontroller as well. Paired with a Nokia BL-5CT battery, he had a working portable power solution for his PDA.
It’s great to see ancient hardware brought back to functionality with some good old fashioned hacking. I’d hoped to do the same with my Apple Newton before someone nicked it from my lounge room, more’s the pity. If you’re rescuing your own beleaguered battery-powered portables, don’t hesitate to let us know!
“The company was renamed Acer in 1987.”…. ancient?!?…. Ohhh…
What could you use that kind of PDA for now? The dock connector contains master and client USB, serial port and speaker output.
as recently as 2008, i used my samsung ipaq 3765 (slightly older than the acer in question) to read a book while on vacation. it was already hampered by poor battery life, but i always kept it near its charger so by that time it hadn’t rebooted in about 5 years (which was essential because its storage was a ram disk). it was perfectly adequate for the task.
the thing is, “it would have been better as an android app” :)
as an aside, my nokia n810 (slightly newer than this acer n30) got left on a charger when it was retired, and it had continuous uptime from 2010 to 2022, doing nothing except periodically answering ssh just to see if it was still there. not sure why it rebooted in 2022 but it has been steady since then too. speaking of things obsoleted by smartphone apps.
thanks for your reply
I still use my N810 to write up scientific articles (LyX on Debbie) in very crammed places (metro).
This writeup doesn’t make sense. Was the gas gauge chip on the PDA a BQ24025 or a BQ26500? Why would the device try to communicate with a chip other than the gas gauge it was built for? Had the device firmware been previously reprogrammed for a previous battery hack?
Apologies if you found the description confusing. The 24025 is on the motherboard and responsible for charging the battery. It has no “smarts” and does not interact with the gas gauge. I mention it specifically because its role seemed misleading when I first expected to see a BQ* chip.
The 26500 is in the battery pack, and the device is supposed to communicate with that one.
The article makes perfect sense. It talks about two different chips, which should have been obvious from the fact that they have two completely different IDs and descriptions. The charger chip is in the PDA, and the gas gauge chip is in the (dead) battery pack.
A replacement generic battery doesn’t have the gas gauge chip in it and the PDA uses the presence of that chip to detect a battery, not the battery itself.
Se here:
https://www.digipart.com/part/BQ26500%20
The battery type for the Acer N30 can be ordered online. 🤔
How much is an STM uC? If less than 10$ then good value lol