DIY Internal Resistance Meter Probe from Old Earbuds

If you are interested in DIY internal resistance meter probes, you might want to take a look at this article.

If you happen to have a cheap Bluetooth earbud charging case cover and a pair of Bluetooth earbuds that no longer work, and you feel it would be a waste to throw them away, you can disassemble the earbuds, keep the magnets for later use to attract screws, and also keep the circuit board.

When you notice the retractable charging contacts of the earbuds, you suddenly come up with the idea of making a probe for an internal resistance meter. If you also happen to have an XH2.54 connector with wires, once you have all the materials ready, you can start working.

First, you need to remove the spring contacts; heating them with a soldering iron is enough.

Then you find something to fix the contacts in place and solder the wires.

After soldering, you use hot melt glue to secure them onto a bamboo stick. You fix the wires with tape.

Done.

You take out a section of a battery for testing, and it works normally.