Power supply, test and calibration - Alimentation, essai et étalonnage

After a couple of modifications on the new PCB, I mounted it on the robot and started to use the new voltage monitoring function.

Yes, I had to modifiy it :

First, I must admit that a I made a major mistake when designing it... The ADC0831 input line was not at the right polarity. It would have not been a big deal if I had tested the PCB without the ADC on its socket. I should have gone to sleep instead of burning one these integrated circuit... Good thing I ordered a spare one.

Moreover, The potentiometer I chose for the voltage divider bridge (9,6 V to 5,2 V max) was to light, which means the current accross it was to high, which means it got warm pretty fast and it was probably consuming way to much power...

It's always good to remember the basics like ohm's law...

Layout for prototyping board

Everything seems to work properly now. I started to try the embedded voltage monitoring tonight. What I need now is to figure out a conversion law between the actual voltage and the value read through the ADC. I run the code below on the BS2 to collect these values in excel :

' {$STAMP BS2}

' {$PBASIC 2.5}

'mesure tension

'ADC0831

'init

adcbits    VAR Word

cs         PIN 9

clk        PIN 10

dataoutput PIN 11

DEBUG CLS

'main

DO

  GOSUB adc_data

  GOSUB calc_volts

  GOSUB display

LOOP

'subs

adc_data:

  HIGH cs

  LOW cs

  LOW clk

  PULSOUT clk,210

  SHIFTIN dataoutput,clk,MSBPOST,[adcbits\8]

RETURN

calc_volts:

RETURN

display:

  DEBUG HOME

  DEBUG "8 bit bin val : ", BIN8 adcbits

  DEBUG CR, "dec val : ", DEC3 adcbits

RETURN

After collecting around 10 values, I should be able to write a "standard" piece of code, easily reusable in each new mission / program.