It would be convenient if it worked that way, but since the batteries are connected across each other in parallel, they will both be discharged simultaneously. And as soon as you hot-swap one of the nearly-discharged batteries for a charged one, it'll be more-or-less short circuited across its discharged counterpart. To do what you describe, you would need additional components to "switch" one battery at a time into…
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Yes, that is exactly what I said at the beginning of this thread.
I want my Blackberry back badly, and this project is giving me hope. The case it a bit too big, there are still battery issues, and of course a 5G card + microphone + loudspeaker need to be added. But perhaps the day will come that I can roll that wheel to view my emails again, use that excellent small keyboard to reply without having to touch glass.
If that thing had VGA-in on top of the keyboard and mouse out via USB, it would be a great tool to carry in a data center when you have to physically interact with a machine.
Are there any compact 4G/5G boards which can be plugged into this for outside connectivity? Last I looked, these breakout boards were far too cumbersome.
I think connectivity would be a key challenge for this device. RPI zero2W only has WiFi4 == 802.11b/g/n. In a modern crowded building, 2.4GHz is often super crammed and busy, and I find wifi4 barely works. Lots of dropped packets, sometimes full seconds of latency.
There's no problem if you use one battery, and there should also be no problem if you use two batteries and charge/discharge them both simultaneously (because then the voltages are matched). The problem shows up when you try to "hot-swap" just one of the batteries and replace it with one at a different state of charge, as the README claims you can do.
What is the expectation here about functionality? They are using some kind of COTS battery system to keep the cost down, but at the consequence of this safety qustion. Should these people expect any buyer to antipate this? Its not really a consumer product after all. I think there is no shortage of battery management ICs, but the number that can arbitrate between external power/battery A/Battery B certainly eliminate…
IMO my expectation is that they not do that. If they want to offer hot-swappable batteries, they should either do it right (with a more functional battery management IC or a little homebrewed FET-switching circuit), or they should at least come up with a hack that doesn't threaten the battery safety. For example, have a physical switch to select between the two batteries and instruct the user to flip it when one gets low. Use a super capacitor to cover the short time while the switch is between connections.
> There is a red switch on the left side to decide if the keyboard controller communicates with the HackberryPi or with other device through the USBC-Port underneath.
OK, having it be able to function as an emergency USB keyboard is pretty cool, though I think I'd prefer emulation of a USB device so I could run a sequence of commands, inject usernames and passwords for logins, etc.
FYI, there was a board named Hackberry over 10 years ago not related to the Raspberries. It employed the Allwinner A10 CPU and had WiFi on board, which was not common back in the day. It however lacked any exposed GPIO which made it unsuitable for hardware hacking, but had good audio (much much better than the RPis available back then) and decent overall performance. I still have one somewhere and recall using it both as webradio receiver for music and with SDR dongles using rtl_tcp. Later, smaller and better boards such as the NanoPi M1 turned out more useful for remote SDR applications.
I wasn't expecting to see buy now links, so I wasn't too disappointed when I did see them but found they both say out of stock - was completely ready to impulse buy the BB Q20 keyboard version (or either, really!) and hope that having registered to hear it more being sold I'll be able to get one. I'd almost be tempted to try to put one together myself, but it's not something I'd find particularly easy and there's oth…