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+--- Thread: 5V DC Input (/showthread.php?tid=2935)
5V DC Input - italo - 05-22-2023
hi, first of all thanks for the great product. it fits 100% to our requirements.
we use the board togehter with home assistant and ESPhome V 2023.5.2.
We like to messure Temperature via NTC sensors. We use this settings.
10K NTC
9.89K resistor
5V DC Power Supply
Connected on INA1
We get a wrong temperature reading. If we connect the 5V DC direkt to the INA1 input we get max. 3.03V on the GPIO36. As we see you use a LMxxx bevor the ESP32. Is the conversion of the 5V linear
to the 3.3V input of the ESP32? Do you have any hints? as the reference_voltage we use 3V because of the limitation of the ESP32.
BR
Giuseppe
ESPHome Code:
sensor:
- platform: ntc
sensor: resistance_sensor
name: NTC Temperature
id: INA1_TEMP
calibration:
b_constant: 3950
reference_temperature: 25°C
reference_resistance: 10kOhm
# Example source sensors:
- platform: resistance
id: resistance_sensor
sensor: INA1
configuration: DOWNSTREAM
resistor: 9.89kOhm
reference_voltage: 3V
name: Resistance Sensor
- platform: adc
id: INA1
pin: GPIO36
attenuation: auto
update_interval: 5s
name: "INA1"
RE: 5V DC Input - admin - 05-22-2023
can you draw paper how you wire. we can test it as your wires.
RE: 5V DC Input - italo - 05-23-2023
hi, attached the file as requested.
RE: 5V DC Input - admin - 05-24-2023
After a simple simulation, the voltage should change, but our reference voltage may not be the standard 3.3V, so it needs to be calibrated.
The 0-5V incoming signal is divided by 1% precision resistors on the board, the voltage follows, and the limiter enters the ESP32 ADC port.
NTC10K This circuit may not be sensitive to temperatures below 20 degrees, so it cannot be tested