MEP EP#338: Feature Complete or Minimal Viable Products
Project DiffProbe
Landed on the topology Stephen wantsHigh voltage dividersCompensation capacitorsCMRR calibration (120dB rejection)Offset correctionBuffers and Instrumentation AmplifiersDifferential Stage10x and 100x attenuation means offsets have to be bang onOpamps (3 of them)BuffersLow input bias currentLow offsetBandwidth?Differential ampLow offset. Capable of driving 50 ohm load to the scopeGain setting resistorsVishay ACAS 0612 - Precision resistor network4x0603 resistors to make a diff amplifier with a gain of 2 Relative tolerance of 0.05%Worst case relative temp-coefficient 15ppmFirmware is “feature complete”Display CommandsHow the vending motors actually workINA219 Current SensorInterruptsImproved method for next revision?The one byte Serial Buffer problemNEOPIXEL (WS2812) vs APA102 (SK9822)Blocking functionsDMA - Direct memory accessImportance of full system integration testing Timer Lockouts for motorsIs there a better way?