New Multimeter Probes Out of Two Ball Point Pens

Shopping at a thrift store I found an old analog multimeter for a dollar. It had no batteries and no wire probes but did not seem like the selector switch was broken and for a dollar I thought if I could get it working by just adding the two AA batteries and make two probes that it would be a good price. This would allow me to have a multimeter (not my good one) for my truck for checking fuses, battery voltages, or odds and ends that may need checking. My goal was to make the probes out of everything in my junk drawer, electronics bins, and... heres the fun part.... two items out of my wife's purse.... Two old, non writing, dried up, ball point pens!

Some 12 AWG wire, preferably one red insulation and one black insulation with approximately 30 inches for both wires.

I reused some wire from an old battery charger cable as the clips were no longer usable and had corroded.

2 dried up ball point pens

two washers or plastic washers that will fit on the pen point

Two banana jack connectors (one red and one black) to connect into the multimeter ports

As for tools:

Hot glue gun

wire strippers and cutters

a screw driver

solder iron

solder

You will use the pen plastic as the probe handle, the plastic point as the metal probe holder.

The dried up pen stick I did not use nor did I use the spring or back plastic clicker.

Remove approximately 3 cm of insulation from both ends of the wires.

This will allow one end to be tinned with solder for the probe end and the other end will be soldered into the banana jack post.

After inserting the post into the holder, use the nut and screw to attach the housing for the banana jack, make sure not to pinch the wire insulation.

Solder the one end of the wire into each jack post solder cup.

Let cool... it will be lightning hot!

Insert the post into the plastic housing and screw together the two halves.

Now for the probe assembly! I took a washer and placed it the pen tip and plastic tube and held them all in place and the used hot glue to hold the three items in place.

Next I cut the soldered end of the wire into a probe tip. I used my wire cutter to cut the end at a shape angle to try and give it a fine point at the end. If you want a finer tip you could use a needle soldered into the wire or cut a resistor lead off and solder that at the tip of the wire.

I used hot glue after placing the wire into the probe housing only half way. Filled as much hot glue into the probe tube and while the glue is still hot, push the wire until your probe comes out the pen tip.

Do this for the other probe. Make sure to match up your wire color to your banana jack if they are to be coordinated red to red, black to black. I even used the pen that had a black plastic tip for the common probe and an orange tip for the positive probe.

Next check that your probes measure a short (and for me, checking that the meter works as well!) As close to ZERO Ohms by placing the probe tips together and holding them.

I had a Ohms adjust on my analog meter to make sure it was reading zero when placing both probe tips together by adjusting the wheel.

I used a know good resistor to check the accuracy and a AA battery to check out the voltage function.

Taking an LED lead out of a know good circuit (placing the probe where the LED lead went to and the other probe to the LED lead, and turning it on) and measuring the current through the LED, I verified the current mAmps meter was also working.

The meter worked! AND my new meter probes were just perfect for the usage/reuse of dried up ink sticks and some wire repurposed from my old wire bin!