Sometimes in the lab there is need to monitor the power parameters during some period of time and put it on a nice graph.
Because I couldn't find something like this and because it is fun to make things, I start to wonder what if I put an Arduino on a power supply!
So, the lab supply must have:
-Variable voltage between 1- 14.4V
-Serial output with time markers
Because I am lazy, I used some ready-made modules.
The main power supply is a modified 12V/5A SMPS; with a little tweak it now deliver 17V/4A.
The variable output voltage is made with a DC/DC Step down module able to handle constant voltage from 1.25 to Vsmps - 2V at around 5 A.
The output voltage and current are measured with the Arduino ADCs and I used two 2.5 LM4050 precision shunt reference in series to have Aref at 5V.
The DC/DC Step down is controlled with a PCF optocoupler driven by a digital potentiometer MCP41010 on SPI.
The output relay is used for fast protection as a "crowbar" circuit and, in the future, will connect the output to a controlled discharge circuit to characterise batteries.
By code, this power supply can be used to deliver regulated voltage and monitor the current or to charge various batteries.
The code is on Github.