Probe Holder

thingiverse

If you've ever had to hold a scope or meter probe on a circuit board with one hand, while typing or doing something else with the other, then this print is for you! This model combines a hollow ball-and-socket chain, combined with a base with a slot to clamp on a PCB board (default is 1.6mm, but can be changed in the .scad file) and a pin-holding probe tip. Print as many of the ball_socket.stl model (chainSocket() module) as needed to reach across the board. Print one of the ball_socket_pcb_clip.stl model ( pcbClip() module) to hold it onto the edge of a PCB. Print one of the ball_socket_probe.stl model (probePinTip() module) to add to the end. After assembling the base, chain and tip, strip a few mm off the end of a length of wire-wrap wire and insert at right-angles into the end of the tip (will probably need to clear the hole a bit), then insert a straight pin to capture the wire and provide a connection to the pin. Stretch out the chain and lace the wire through the holes in each link. Strip the other end for clipping by a scope or meter. The long, thin strip holding the tip is to provide the necessary spring tension to keep the pin-probe held down. If it cannot be flexed against the board w/o movement in the chain, then the tightness factor will have to be increased, or more filament used when printing. I used PLA with a 0.4mm tip, 0.2mm layers - smaller could make for prettier parts. Depending on your printer, you may need to vary the "TIGHTNESS_FACTOR" global to tighten up the chain, or make it easier to snap together. Update 4/3/19: reduced TIGHTNESS_FACTOR to 0.93, for a stiffer chain. Update 7/13/19: PLA tends to wear and loosen the chain. This can be overcome by disassembling, then dipping each socket end in boiling water for 10s, then pinching just slightly to tighten up. Will test using other filaments to see if they are more tolerant to wear.