I want to measure on the ADC from the ESP8266-12 module the voltage provided by a Hall current sensor - specifically an ACS712 20A with 100mA sensitivity.
The ACS712 module as it is known operates on a 5V bus. There is 2.5V on the middle pin of the ACS712 which is supposed to lead to the analogue input. On the ESP8266-12, on the other hand, we have an input in the range from 0 to 1V where the input itself operates on a 10-bit converter. That is, the possible logic states for this input range from 0-1024 depending on the voltage.
To make the voltage on the analogue input match, I made a voltage divider using resistors.
I made a voltage divider using resistors R1 (220k) and R2 (100k) which gives a voltage of 1/5. I now have about 0.5 V at the output, but unfortunately the signal looks terrible. It completely misses the current waveform that the circuit originally delivers before applying the divider.
What can I do to improve this signal? Will lower resistors help? I also have a problem with the voltage filtering because I sometimes get peaks that deviate by 1/10th of the scale of the converter. I try to filter them digitally by writing functions in C. Unfortunately I am not happy with the quality of the measurements using the divider.
The ACS712 module as it is known operates on a 5V bus. There is 2.5V on the middle pin of the ACS712 which is supposed to lead to the analogue input. On the ESP8266-12, on the other hand, we have an input in the range from 0 to 1V where the input itself operates on a 10-bit converter. That is, the possible logic states for this input range from 0-1024 depending on the voltage.
To make the voltage on the analogue input match, I made a voltage divider using resistors.
I made a voltage divider using resistors R1 (220k) and R2 (100k) which gives a voltage of 1/5. I now have about 0.5 V at the output, but unfortunately the signal looks terrible. It completely misses the current waveform that the circuit originally delivers before applying the divider.
What can I do to improve this signal? Will lower resistors help? I also have a problem with the voltage filtering because I sometimes get peaks that deviate by 1/10th of the scale of the converter. I try to filter them digitally by writing functions in C. Unfortunately I am not happy with the quality of the measurements using the divider.
