How fast and how cheaply can test equipment be made? Two can be made for less than 5 dollars, an hour of time and a glass of wine with my sweetheart. A great Wednesday night.
Door / Window Alarm
Bicycle Light
Audio Cables / Test Probes
Batteries
Door / Window Alarm depackaged
The one screw that needs to be removed
The magnetic swtich
Bottom of the PCB – see the blob? That is a "chip on board"
Audio cables cut in half to make two sets of leads
Stripped all the way down and twited together (stereo to mono)
Clip the wire leading from the circuit to the battery
Attach the probe wires to each lead
Finished Tester I
Bicycle light depackaged
With the pastic diffusers removed
Bottom of the circuit board
Stripped lead wires with a cardboard interrupt
A little help pressing the momentary button while testing the probes
The finished testers I and II
“Real parts” like a battery holder, mini buzzer and alligator clips along with wire with some solder can be had from the local Radio Shack, but that is way more expensive. Biggest tip, keep the circuit under 3 Volts. For testing sensitive circuits, it will be time to uplevel.
Much better DIY continuity tester http://www.xtechnik.szm.com/Files/Zapoj/akust_skusa.html
Yes! If you want to build one from scratch. Very true. Thank you for sharing. I’m assigning this project again so I thought I’d add yet another link with some more continuity tester circuits.
http://kripton2035.free.fr/continuity-repos.html
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