If you are a DIY beginner, I recommend following through with these instructions. Otherwise, go ahead and build the circuit and then continue on to the calibration page if the display seems to be working or the debugging page if it doesn't (there is a special mode in the PIC to assist with debugging). Please see the hardware page for more specific information about how this circuit works. It is not required that you understand, but it will most likely make figuring out problems later (and avoiding them to begin with) much easier.


  • Must collect all of the necessary parts and tools
  • Must posess rudimentary soldering skills
  • Tools:
    • Drill or some way to put a few holes into the lid of your jar
    • Wire strippers (knife or scissors will do)
    • Wire cutters (knife or scissors will do)
    • Soldering Iron
    • Solder


  1. Circuit
  2. Enclosure
  3. Testing

At this point, if you are extremely lucky, the EnerJar will display some fairly consistent value. The numbers won't be correct yet, but you can fix that by calibrating it.

Next steps
If the display does not show any numbers, no LEDs ever turn on or something isn't working the way you expect, continue on to the debugging section (this is expected. Don't worry, there is a special mode in the PIC to help you figure out what is going wrong)
If the display shows numbers, and the size of number seems to change when you plug a device into it, continue on to calibration.