DIY Miniature Multimeter -- Episode 483

Here are some interesting question is want to adress:
by user Cliff Matthews

I don't know why the typical breadboard end-type PCB format wasn't chosen as the base PCB (you could put your 3D plastic contraption around that..). Also, most everyone has a access to an old Android phone, so why u$e an OLED display when there's a much bigger one (with data logging) on the phone? Another thing, I see you chose a Lion battery and charger to isolate the INA219 and ESP from the hobbyist's various power scenario's, but open Lion cells are typically for portable power and pose their own safety risks... why not help the hobbyist by using a DC-DC converter instead for DMM isolation?

shape:

     to make the premise more tangible I chose to make it look similar to my klein mutlimeter /typical multimeters

android phone:

     It is compatible with any phone I showed in the video that you can access the measurements with any device on the same network. the section where i talk more about viewing on the phone ended up on the cutting      floor, as it was not core to the project.

battery:

     I choose a lipo first to get myself familiar with designing charge circuits for them and secondly to make this device truly portable. a tiny multimeter will be handy in more situations than just on a breadboard.
     also it avoids power loops that might occur when hocking it up incorrectly. and it does not draw power from your project which might make the measurements unusable or give a fals impression of the projects power      requirements.

Some things I like to improve are:

     Isolation, I like to use tiny isolation transformers to decouble the I2C and Measurment lines.
The code needs alot of improvement in general

I'd like to replace the screen with a more standard one that works better with the libraries.
I'm searching for a better way to plug breadboard wires into the multimeter in a locking fashion, but hassle free... maybe wago terminals?

let me know if you have any ideas!

Using an Android phone as an external screen would be brilliant, particularly for situations like remote measuring where you can't be near the DUT, but I wouldn't want to use a phone as the sole screen for the device. Sometimes I wanna grab a multimeter for a quick measurement, and having to also grab my phone, load the app and wait for that to load would be a real workflow breaker

Using an Android phone as an external screen would be brilliant, particularly for situations like remote measuring where you can't be near the DUT, but I wouldn't want to use a phone as the sole screen for the device. Sometimes I wanna grab a multimeter for a quick measurement, and having to also grab my phone, load the app and wait for that to load would be a real workflow breaker

thats why it has both