Resus Anne compression sensor

The compression/ventilation sensor in the Resus Anne / QCPR manikins from Laerdal have been the subject of previous posts where I looked at the implications of the linear optical encoder on ventilation volume measurements.

Another issue that we have encountered several times is that one of the wires that connects to this module fatigues over time and eventually breaks internally (the white one).  The pattern when this happens is typically a gradually decreasing measured depth of compressions until they don’t measure at all.

overview

The wire connects to the sensor module with a small IDC (insulation displacement connector) from TE/AMP (173977-8) which are $0.75 USD each from Digikey (A98616-ND) or $0.95 AUD each (in a pack of 10) from RS Components (680-1304).

connector

Unfortunately, the tool to insert the wire is ~$1300 USD 😦  58074-1 Hand crimper without die set – Digikey Part A2031-ND  $105.77 USD + 58372-1 Tool head assem 2mm terminator
Digikey part A99129-ND  $1,191.20 USD

crimp-tool

So naturally I made my own punch tool.  Not as fancy, but should get the job done.

tool-tip

The tip is a piece of stainless steel out of the scrap bin.  1.15 mm thick, ~5mm wide

The tip is cut/filed down to 3mm wide by 3.25mm high with two slits in the end.  These slits were cut with a jewellers saw using a 3/0 blade (0.24mm = 0.095″wide) and about 1 mm deep (because I got tired of cutting) about 0.75mm from each edge of the tip and just over 1mm apart.

This drawing was taken off the official connector drawing.  Ignore the tolerances.  Close enough seems to work fine.

drawing

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