Static dissipative wand for discharging yourself to avoid nasty shocks in a low humidity environment.
I was getting zapped all the time at my new job, the floors here and my shoes must be quite a way apart on the triboelectric series. So, I built this discharge wand as a bit of a joke, but it is actually pretty handy, and doubles as test equipment.
1x NE-2 neon bulb (5 mm OD)
1x 39kR 1/4 W resistor (not critical)
2x Brass caps (or copper tape, tube, etc)
Print two body pieces, solder the resistor and NE-2 bulb in series. Place NE-2 bulb so it is visible through the hole in the wand wall. Fold wires over the ends and cut to length, then secure and assemble by pushing on the end-caps.
OpenSCAD file is parametric to accomodate different geometries. I just happened to have two brass caps in the junkbox here that worked well, you can use copper tape, or pieces of brass tubing, or anything else conductive, spheres, whatever. The resistor value is not critical, the smaller it is the more of a chance that you'll feel the current pulse, larger values up to a meg or so will be fine. 10s to 100s of kR are ideal for seeing the flash. You can put a small capacitor (say 1 nF) across the NE-2 and have it blink a few times, or flash while testing ionisers.
Obviously you don't need the neon bulb, and it cuts off at about 60 volts, so it leaves you slightly charged. You can just use a 1 meg resistor if you want, but I like the flash feedback of successful discharge. You won't feel the residual charge.