George shares how to make a battery backup circuit for your RPi via repairhub.co.uk:
This is a step by step instructions on how to make a battery backup circuit for your Raspberry Pi computer. For more information about Raspberry Pi visit the Foundation’s website.
First I’d like to explain a little bit about what I tried to achieve with this design and also pros and cons of this approach. I’m using my Raspberry Pi as a backup device with two hard drives connected to it, to back up various online servers that I administer. I use automated backup scripts based on Rsnapshot, and also I’m using this particular Pi as an Apple time machine server. Because Raspberry Pi is a very low power device, I thought it would be possible to design a cheap backup power supply using a 9V rechargeable battery, and this way prevent any abrupt shutdowns during power cuts or when someone accidentally unplugs it from the mains. As an added feature it also will provide a convenient way to safely power the device off without adding a hardware button or logging-in remotely and issuing a shutdown. But what this circuit doesn’t currently do is monitor battery levels, nor provide any kind of low voltage cut off, but there is a time limit/delay after which it will automatically power off and disconnect the battery.
The finished circuit does the following:
- Trickle charge the battery while on mains power
- Send a signal to Pi GPIO pin when mains power is disconnected
- issue a shutdown after a few minutes if power haven’t returned (Done via software)
- disconnect the battery from the circuit after shutdown is completed (this is to prevent discharging the battery below its limit)
- keep a log file with all the time stamps and alerts for mains power, shutdowns and restarts of the Pi
Check out the full tutorial here.
Have an amazing project to share? Join the SHOW-AND-TELL every Wednesday night at 7:30pm ET on Google+ Hangouts.
Join us every Wednesday night at 8pm ET for Ask an Engineer!
Learn resistor values with Mho’s Resistance or get the best electronics calculator for engineers “Circuit Playground” – Adafruit’s Apps!
Maker Business — Undercover in an iPhone Factory (video)
Wearables — Go with silicone
Electronics — Shift away from basic arithmetic
Biohacking — Bunnies Book “The Hardware Hacker” Applies to Biohackers
No comments yet.
Sorry, the comment form is closed at this time.