Logging Power Consumption

Other Hardware General Electronics
1

I'm planning a project using a Rasp Pi and the SleepyPi shield: the SPi is an Arduino that is basically tasked with shutting down the Pi when it's not in use. Since the Pi is a powerthirsty monster in this project, it doesn't need to be on all the time. Specifically, the Pi will be booted, Take a photo, upload it to the internet, and then shut down. It will probably do this once an hour or when there is a PIR trigger.

When I deploy the project in the field it will run off solar and either a LiPo or a Supercap. Before I decide that and go buying and building the power supply I want to power this at home for a while and simulate normal use conditions.

I need some way of logging the actual current consumption of the project over time. During most periods the Project might only take 1-2 mA of draw, while at other points it might be drawing 600-800 mA.

What would be an effective way of logging that? Preferably without buying extra, sophisticated parts.

2

Use a multimeter and have your camera take a picture of the meter periodically. :slight_smile:

Rather than log current, there may be other ways to solve your problem. One might be to measure current with a meter while your project is in various states. Then log the state of the project and infer current from previous measurements. If you are looking to find out energy usage from your current measurements, you could simply time how long your project runs from a known supply of energy (battery, supercap).