[Adr990] wants to make sure his Game Boy game saves aren’t lost to aging batteries. They’re stored in SRAM with a small coin cell inside the cartridge to keep the memory energized when the game is not being played. But if you pull out the battery in order to replace it the data will be lost in the process. It turns out that you can hot-swap the battery without too much effort. As shown in the video after the break, he disassembled the case of the cartridge, then replaced the battery while the Game Boy is switched on. The edge connector feeds power which will keep the SRAM active while the backup battery is removed. We’re sure this could be done with a bench supply as well, but you’ll need to do your own testing before risking those prized game saves.
The other option is to backup your SRAM before replacing the batteries. We’ve seen an AVR-based cartridge dumper, and also one that uses an Arduino. Both should be able to read and write SRAM data. Continue reading “Simple trick for replacing Game Boy cart batteries while retaining game saves”
[Photonicinduction] has an impressive battery backup installation that powers his whole house. Unlike a standalone emergency generator which would require you to hook up all of the device you want to run, this setup sits in between the power meter and the breaker box, ready to step in when needed.
But get this, he’s not just using it as a backup system. It kicks in during the day to run everything including two freezers, a refrigerator, his lights, television, and computers. That’s because the price per kilowatt-hour is quite a bit higher during the day than at night. So after 10:30pm the system patches his house back into the grid and charges the batteries for use the next day.
What you see here is just a portion of his system. The control board is not pictured but is very impressive, including a network of relays which are used as a fail-safe system so that there are no conflicts between mains and the battery system. Check out his 15-minute walk through of the system after the break. Continue reading “Whole house battery backup used for lower power bills”
[Surferdude] was unhappy with the decreasing life of his aging uninterruptible power supply. He decided to beef it up using marine batteries. He extended the battery connections outside of the UPS case using #10 wire and swapped the two 12 volt gel cells with the heavy duty lead-acid batteries. Doing so upgraded the device from 20 amp-hours to 84 amp-hours at a cost of about $160. If you’re thinking about taking this on yourself, pay attention to the countinuous output rating of your UPS to prevent a fire risk.
Looks like they’re at it again over at Adafruit. This time they’ve produced a clock that looks more like it should be attached to a munition rather than cruising bedside. But, geek-cred aside, there’s a lot to be learned from their design. Like we’ve grown to expect, they’ve put together some good documentation on their choice of components.
Start off by taking a peek at their 5v power regulator. There is an extra diode on the output side that prevents reverse current from the 3v backup battery. The AVR ATmega168 that controls the clock is used to detect loss of power and quickly shift to the battery backup. They’ve also used the microcontroller as a boost converter for the high voltage VFD, a nice trick we’ve seen before.