Pin Probe as published in the eTextile Swatchbook 2017

The Pin Probe is a test lead to connect between a multimeter and conductive fabric or thread. The probe consists of a pin to make temporary but firm contact with textile materials without harming them. A soft and flexible textile cable then connects the probe to a banana plug to connect to a multimeter.

The Pin Probe is designed to aid processes of textile electronic making, allowing to pin the probe to the textile material and have both hands free for the crafting routine. Directly while stitching the connection, the multimeter provides continuous information about its current electrical value. The immediate feedback allows instant action, facilitating an aesthetic-driven workflow to reach precise electronic results.

This instructable shows the making of a Multimeter Pin Probe. But you can also make a prototyping cord with pins at both ends, if that is what you rather need, or with a clip, or any other connecter at the other end.

(This is a copy of the instructions on http://www.ireneposch.net/pinprobe-diy/, 2017)

Step 1: Materials

4 mm banana plug
9 mm shrink tube (3:1 shrink ratio is ideal)
paracord (or an other flexible cord that lets you puush through a thread in the middle)
conductive thread (I am using a 7×5 copper thread from Karl Grimm. if you have a thinner or less conductive material bread it together or use several strands to increase the conductivity. you can also use a flexible cable)
3D printed handle (Shapelock could also be used to form a handle if no 3D printer is available)
pin (stainless steel, or other highly conductive material, should not have a coating)

Step 2: Tools

scissors, cutter knife, glue gun, lighter, screw driver, multimeter, solder iron, solder, needle
3D printer if you want to print the handle (download below)

pinholder_new_190517.stl
Download View in 3D

Step 3: Schematic Drawing

Step 4: Preperations

cut app. 1 meter off the paracord (you can adapt the length if you want your probe cord to be longer or shorter. To connect to the multimeter, 1 meter is a good starting point.)
pull out the inner nylon cord

Step 5: Textile Cable

thread a (stump) needle with the conductive thread (or cable) and push it through lengthwise through the paracord until it comes out at the other end
when pushed through, remove the needle and make a knot
spread the paracord coating evenly across the conductive core
be carful the conductive thread does not slip through
make a knot at the end

Step 6: Connect Banana Plug

put some solder on the knot (this is optional, but I it makes it easier to establish good contact)
push the knot into the banana plug
fix it, screwing the screw in
try pulling on it to make sure it is fixed
slide the end of the cord coating into the banana plug as well
cut of the fraying ends of the conductive thread

Step 7: Fixing Banana Plug

measure the resistance between the connector part of the banana plug and the conductive thread at the other end of the cord. the resistance should be below 1 Ohm but depends on what material you are using
if all looks good, use the glue gun to fix the conductive thread and cord into the banana plug
cut a 3 cm piece from the shrink tube
cover the banana plug with the shrink tube and heat it so the tube shrinks around the banana plug and the first few millimeters of the cord
let it hang verticallly so the glue hardens with the cord in the middle. this side of the probe is now finished

Step 8: Preparing Pin Probe

cut the conductive thread on the other side leaving it 3 cm longer than the covering cord
pull back the cord a bit and make a knot where the conductive thread exits the cord
push the pin through the knot
(optional: fix the knot with a drop of solder, make sure the drop is not too high. if you are using a cable, solder the cable to the needle)
cut off any fraying ends of the cord (you can burn them carefully with a lighter)
measure the resistance between the banana plug and the pin. the resistance should not be higher than what you measured last time
cut off the rest of the conductive thread, or cable

Step 9: Pin Probe

place the needle in the bottom part of the handle (the bigger one) so that the connection between the needle and the cord sits in the middle and the needle is pushed through the small opening in the handle.
you can use some glue to close the handle with the 3D printed top (be careful not to use too much glue)
quickly place the top before the glue dries
hold the glued handle together for a little while until the glue is dry/hard

Step 10: Finishing

measure the resistance between the two ends of the probe
the resistance should not be higher than what you measured last time, ideally it is lower, as everything is closely glued together now
you can do the measuring in plugging the Pin Probe into the multimeter and contact the pin with the other probe
the Pin Probe is now finished