Resistor Requirements for Sensors
Thought for 32 sec
What’s currently in your schematic (power + data)
Runoff 1-Wire temperature connector: Runoff Temperature Sensor
- Pin 1 = Net 5 (Power rail)
- Pin 2 = ONEWIRE_DATA (to ESP32-S3 DEVKITC-1 GPIO5)
- Pin 3 = GND
- Pull-up present: R2 = 4.7 kΩ from ONEWIRE_DATA to Net 5
DHT11 connector: DHT11 Temp and Humidity Sensor
- Pin 1 = Net 5 (Power rail)
- Pin 2 = DHT_DATA (to ESP32-S3 DEVKITC-1 GPIO6)
- Pin 3 = GND
- Pull-up present: R1 = 4.7 kΩ from DHT_DATA to Net 5
- For pull-ups specifically: you already have one pull-up per data line (R1 for DHT, R2 for 1-Wire). In the typical case, no additional pull-up resistors are needed on the PCB.
- The main “gotcha” is the opposite: if your external sensor/module already includes its own pull-up, you can end up with multiple pull-ups in parallel (effective resistance becomes lower). That usually still works, but it can increase idle-line current and sometimes makes edges too sharp/noisy on long cables.
Both pull-ups go to Net 5, so make sure Net 5 is the voltage you actually want those sensors pulled up to (likely your 3.3 V sensor rail in this design). If you tell me whether you’re using bare sensors vs “modules” (breakout boards), and approximate cable lengths, I can say whether you should keep 4.7 kΩ or adjust it.
Sensors are bare probes
Sensors are breakout modules
Verify Net 5 voltage
Add optional series resistors
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