Digital Testpen

 A week ago i received a cheap digital test-pen from china. I already mentioned in my mailbag post that i would post something about two small cheap upgrades. 

This cheap device can be used to test digital signals. it contains of a pcb with a wire as test pin and Dupont cables and comes in a sealed plastic bag. There exist several schematics to build these kind of devices yourself. However this was a cheap (almost) finished product on AliExpress.

I did two little cheap hacks to enjoy the use of this device even more. However first a photo of the back of the pcb to get a complete visual impression of the device.

As not all points always have Dupont connections i added male Dupont pins to small alligator clips. Using this alligator clips attached to the wires the testpen can also be used if no Dupont pins with power are available in the circuit you want to test. 

After soldering i even decided to remove the plastic of the male pin.

The second easy and cheap hack is using transparent heat shrink over the PCB to protect it. It can be done very easy and adds protection to the test pen pcb circuit. All you need to do is cut some transparent heat shrink tube at the appropriate size. Put it over the pcb and shrink it with a hot air gun.
If you want even more protection you can use a hot glue gun to first add a glue layer. For my use of this device i expect the heat shrink tube will be sufficient. 

Below you see the result: