ESP32 Forum

Hello,

I'm trying to use ESP32 to modulate throttle response and provide a dashboard for an ebike. I need to read throttle voltage, battery current, do some calculations and output the new voltage, and also read battery level and show speed/RPM from a hall sensor pulse. And I need to make some settings from the throttle adjustable via WIFI (power modes)

Space is very limited and I could not fit an ADC in the project.

Throttle values are 0.9-4.1v, I'm using a voltage divider with two 10k resistors.

Current sensors are 2.5v-4v, R1 and R2 are 10k.

Battery voltages range from 59-86v, R1 is 40k, R2 is 1k.

Hall sensor pulses 3.3v, I'm using a pulldown resistor.

My ADC readings are a complete hell, I get 0 and 4095 readings all the time, so I could not find any way to filter out the noise and get any readable value. (EMA, SMA, median...)

ESP32 is powered with a 5v buck conversor which also powers current sensors, and it is powered by the ebike battery (so a lot of voltage sag when using throttle).

Is there any hope to get ADC readings from internal ADC? If so, should I make any changes in the circuit? Use bigger resistor values? Use a 3.3 voltage regulator on ESP32 Vin?

I really have no clue on what to do and would really appreciate any help provided.

That sounds like a very noisy environment indeed. Perhaps some capacitors on the ADC pins can help a bit in cleaning up the signal? (Something like 100nF should be sufficient.) Another trick, especially for slower-moving signals, is to take lots of measures and average them to get rid of the noise.

ESP_Sprite wrote: ↑

Tue Feb 21, 2023 12:23 am

That sounds like a very noisy environment indeed. Perhaps some capacitors on the ADC pins can help a bit in cleaning up the signal? (Something like 100nF should be sufficient.)

I tried with a electrolytic between ADC pin and GND and also added another one between VIN and GND, zero results. I've ordered ceramic and they should arrive in two days. (Tomorrow is a national holiday here)

What does the signal look like on an oscilloscope?

I get 0 and 4095 readings all the time

Is there any correlation with the actual input signals in the readings at all?

Can you correctly read a fixed voltage (say from a 1.5V battery) on one of the ADC pins to verify that the ADC is correctly configured?

Are you using ADC2? Note these limitations: https://docs.espressif.com/projects/esp ... imitations