I’m back to writing posts! And expect a long post about my Raspberry Pi wearable PC soon =)
Here I present you a tiny I2C RTC powered by DS1307.
- 5V power
- Possibility to connect 3V battery to save clock value while power is off
- Small enough – 3,5×2,5cm
- All parts are easy to find
Here’s the PCB image I made using EagleCAD. It uses:
- CR2032 holder – can be easily salvaged from an old dead motherboard
- 32,768KHz quartz resonator – same, usually found on old motherboards
- 3x 10K SMD resistors – could either be bought or salvaged like two previous parts
- DS1307Z in SO-8 packaging
This PCB indeed is tiny. The biggest part of it seems to be the battery holder, and I chose this type of holder/battery combination because both of them are easy to find. Also, you can hook up your own battery – there’s a pin for this on the pin header, thus, big holder is not necessary if you’re not using it =) I made this PCB just because I couldn’t find anything like this on the Net. Now it’s your, too, so you just need to print image below on a sheet of A4 paper using 600 dpi and you’ll have it 1:1. Hint: use GIMP for printing images with certain DPI. Should there be questions, I’ll post a guide for doing this =)
Hope this helps you in your numerous electronics projects.
Just FYI again – it’s 5V. Yes, it will burn the Raspberry Pi unless you use a logic level voltage converter suitable for I2C communications. Later I’ll probably tell you about making one 😉
I’d really like to provide Eagle files, but the truth is – I lost them somewhere. I might have a backup somewhere, though =( As soon as I find it, I’ll put all the files here.