Hello everyone, I am working with a very sensitive ORP sensor.
According to the manufacture it is critical that the voltage power supply is stable 5v. So I connected the ESP32 not to my laptop but to an external USB power supply.
Is there a way to display on the serrial monitor the voltage the ESP32 is receiving? I just want to see if there is any variation or if I have a very good stable power suply.
Thank you.
This has been done a lot of times, measuring voltage using a microcontroller. Try Google on ESP + voltage measurement.
You should be using some sort of logic level shifter..
ESP32 is 3.3v not 5v..
They do make usb testers which might be a better choice for checking the power srouce..
good luck.. ~q
thank you.
Thank you but this is not what I am after. Qubits-us suggestion is good. I agree. It is probably better to do that with an external tester before I connect a power supply to my esp32.
Okey. The assumtion here was continous voltage checking.
Using DMM for a voltage check and if needed, an oscilloscope checking the ripple.
An ORP sensor may output an analog voltage. In that case, istead of a logic level shifter, use a voltage divider to reduce the input voltage by a known fraction, for input to the ADC.
But first, study the ORP data sheet to see what the output actually is, and use your multimeter to check. Post a link to the sensor.
Note: the ADC on the ESP32 is so nonlinear as to be worthless for quantitative measurements.
Thank you. Understand. The original code from DF robot has a line to do just that. But thank you. Everything seems to be much more stable after I use a different power supply than my laptop. Love arduino. Learning everyday!
Uploading: IMG_3817.jpeg…
To do what?
The DFRobot ORP meter is a 5V analog sensor. Use a 10K:10K voltage divider to protect the ESP32 input from damage, but don't expect good data from the ESP32.
The Arduino Uno and similar would be a MUCH better choice.
to convert analog signal to orp value. this line. But the sensor is not connected directly to the ESP32. It goes thru a small circuit board first. attached here is the link.
I use ESP32 because I want to upload results to IoT. I also have Nano IoT 33. I want to trigger an alarm is the chlorine level gets below 3 ppm. Since there is no chlorine meter per say, I use ORP measure. I have 3 glasses of water on my desk with 0 ppm of chlorine, 2 and 4. Testing is going well.
But you said I would get MUCH better results with Arduin UNO. I have one. Question. Would I get MUCH better results as well with the Nano 33 IoT ? Because as you know the Nano IoT 33 has wifi built in.
What do you think? Thank you.
A 5V analog sensor won't work with a 3.3V processor, unless you add a voltage divider. The sensor outputs voltages between 0 and 5V.
The ESP32 is one of the worst choices for measuring voltages.
ok thank you
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