Hardware » Cablemeter

h1. Eval

h1. Overall design

* 4 x red+green LEDs for condition
* Restart button
* Rotate over the ADC channels and get Voltage level
* draw 100mA
* Die Kabel haben AWG28, 212.9 Ohm/km, 1.4 A nach erde, 0.23 A versorgung
* https://de.wikipedia.org/wiki/E-Reihe#/media/Datei:E12_values_graph.svg

U2=((U*R2)/R_GES)

U
R*I

5V/0,1A= 50 Ohm
5V*0,1A= 0,5 W

RGes = R1+R2 = 50

3V=(5*R2)/50
R2 = (3*50)/5 = 30 -> 27
R1 = 22
RGES = 49

U2 = 5*27/49 = 2,755102



h1. MCU

* "stm32f051c4":https://www.mouser.de/datasheet/2/389/stm32f051c4-1851079.pdf
** I have 17;
** 16 ADC channels
* STM32G030C8T6
** nearly same specs but smaller footprint; LQFP 48