Fmilburn 445 Posted October 9, 2015 Share Posted October 9, 2015 Some time back I ordered an INA125P Instrumentation Amplifier in order to fool around with a cheap, broken "postal" scale that I had. It arrived and I promptly put it away and forgot it about it. So the other day I was digging through my junk box, saw the scale, and decided to tear it apart. Since it is getting near Halloween, and I knew my grandchildren would be interested, I wrote a little sketch in Energia to estimate the amount of candy in a bowl. Here is a schematic of the circuit. It "works" but given my skills it may not be best. This being a MSP430 project I hooked up the sleep pin on the INA125P. I also made it where I could change out Rg, the gain controlling resistor, easily. Once I had it working I made up a little BoosterPack that goes on the bottom of the LaunchPad. The INA125P sits between the daughter board and the MSP430F5529 LaunchPad - you are looking down on the male pins in the photo above. I hot glued a piece of cardboard on the bottom so as to reduce the chance of shorts and provide a reminder on how to connect it. Below is a view from the bottom with it connected up to the LaunchPad and the scale. The sketch is here on github. There is a little calibration routine it goes through when started up where it asks for the empty bowl and then a known quantity of candy to be placed into it. After that, it displays on a SHARP96 BoosterPack. I thought about connecting it up to the IOT, but after due consideration decided I didn't want the neighborhood kids knowing how much candy I have left. bluehash, phenyl, chicken and 4 others 7 Quote Link to post Share on other sites
Lgbeno 189 Posted October 15, 2015 Share Posted October 15, 2015 But then again, you could detect when the kids swipe the entire dish and set off some fake police sirens Sent from my iPhone using Tapatalk chicken and tripwire 2 Quote Link to post Share on other sites
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