@grant1842
Hi, I looked at the protesus schematic drawn by you, as I see some things are not right, here are my observations:
- Q2 should be a PNP transistor (BC327) (In your schematic I see Q2 as NPN BC337) not to mention that is not wired up properly, the correct transistors used in the schematic are complementary one is BC327 the other BC337, see original schematic.
- the part that leads signal to the AIN0 pin is not correctly wired either, look at the the original schematic carefully, the diodes and the 10k resistor's (R7 your schematic) one side should be tied to the ground not in parallel with the 470R resistor (R6 your schematic).
- please check carefully with the original schematic to make the proper corrections.
As for the code part you can comment out this part (after you corrected the hardware part):
eeprom_read_block((void*)&esrCal, (void*)0, sizeof(esrCal));
and
if(!digitalRead(BUTTON_PIN)){
lcd.clear();
lcd.print("Zeroing...");
esrCal = (miliVolt)/current;
lcd.print(" done!");
lcd.setCursor(0,1);
//writing calibration value into EEPROM so we don't have to calibrate on restart
eeprom_write_block((const void*)&esrCal, (void*)0, sizeof(esrCal));
lcd.print("saved to EEPROM");
delay(400);
}
After commenting see if you can produce some readings (should be resistance value of wires + resistance of DUT, zeroing is needed only to eliminate the resistance of the cables used, you will uncomment the part of code when you have some meaningful readings and need a proper zeroing.) For when the hardware is corrected you can test if it is working like this: when a DUT is not conected you should read on the AIN0 pin the max voltage permited by the anti-parallel diodes (around 700 mV, depends on diodes) and when the leads to the DUT are tied together this value should drop to a very small value.