pH test module Arduino programming learning notes

Programming Notes:

analogRead: 1023 or 1024?

Esp32 ADC tips

Add library 

Serial.print format hack

Bubble sort

Least square straight line fit math explained

Quickstats

to monitor Arduino Serial output/input:

Alternatively, can use Putty or RealTerm , or serialportassistant github

The pH electrode malfunction after use, for just a few days. KCL solution is refilled, but thus doesn't help. No visual damage. Output is just a few mV. What happened?!!!

No Change even after reference solution drain and refill!!

2 or 3 days after refill change, the reading is ~ 100 mV. Let's see.

Finally found that the inner glass elecrode is broken:

The glass piece was somewhere here

EEPROM read and write:

Keep in mind EEPROM.write is byte operation 

Float is 4 bytes 

Xanthium

YouTube 

YouTube 2

No of sanples.

If change from 40 samples, to say 1000 samples, the Arduino hang up. Likely running out of free memory. Heap memory is eating up all the free memory 

Free memory check , memory use explained 

Megunolink

Sampling.

pH electrode is slow responding. 15 sec or more to get stable reading.

If hydrogen ion is less concentrated, ie near pH 7, takes longer time to stabilise.