RC Aircraft Thrust Stand Version 2 - Hack of a Kitchen Scale for only $10

This is the second RC Thrust stand I have designed with the first being based on an Equal Arm Balance. This one is more compact and does not require you to subtract out the weight of the components to find the absolute value of thrust produced. It flies forward and pulls against the arms that drive into the weight (force / thrust) measuring sensors. Not good at electronics to build something like this, no problem; buy a kitchen scale from amazon (Item # B00MN0NI90, "DecoBros Digital Food Scale") and hack it to harness the electronics. (A possible alternative https://www.amazon.com/Etekcity-Multifunction-Platform-Batteries-Stainless/dp/B076BJG1RN/) I also purchased a 2 AAA battery holder from Radio Shack (shame they are all disappearing around here) instead of reusing the coin battery holder. AAAs will last much longer. Print the parts, Disassemble the scale and take care with the four sensor plates (follow the pictures). After removing the metal plate on top of the scale (a couple of tabs and some double sided tape) I used a Dremel to cut through the plastic frame where shown (be careful of the wires). I used a pair of flush cutters to remove the scale's feet from the sensor plates, don't use the dremel. You don't want to change the metal plates by accidentally grinding them; this will change their accuracy to measure the thrust from the motor prop combo. The plates have strain gauges on them under the sealer and are calibrated to measure the amount the metal bends as force presses on them. For that matter, do not accidentally bend the tongue in the metal plates. You can use screws to secure everything at the hinge points, but I successfully used 12 Gauge Aluminum Wire used to make arts and crafts. It's soft and easy to flatten to a long hinge pin; and the holes are design for this. Clamp or drill and screw the thrust stand to a permanent surface. Make sure you leave room for prop to rotate. Also try and not block the flow of air off the back of the prop.