Using TSic 506F temperature sensor with ESP32 (or other 3.3V Arduino board)?

Hardware
1

Want to build smart thermostat using a Chinese 1,28" knob display based on ESP32-C3 and a TSic 506F TO92 temperature sensor.
I have access just to an I/O pin (not sure yet which one), 5V and GND.
The TSic 506F is known for working best from 5V (if 3.3V needed it should be recalibrated from factroy which might involve considerable costs, so not recommended), but ESP32 accepts input up to 3.3V on GPIO pins (as far as I know).
However I"ve read from many sources that interfacing 506F to ESP32 is pretty simple, “no pull-up resistors or additional components are needed”.
Do I miss something? If I was right, would a simple resistive splitter help? Or do I need cost- and space-intensive active level shifter?

UPDATE: GPIO3 is available GPIO pin. No access to the internal 3.3V.

2

According to the data sheet, the sensor will work with 3.3V processors, but with reduced accuracy.

A 100 nF capacitor from V+ to GND is recommended.

3

Well, if I wanted reduced accuracy I'd use much more accessible sensors, not this expensive one.
The other problem is that I have no access to 3.3V.
Pins I have access to:

5V
GPIO3
GND
RX
TX
RST
D+
D−

(I assume the last pins are for communicatiing through USB.)

4

Why is that, given that the ESP32-C3 is a 3.3V processor? Post a link to the module you have.

You can use the sensor with 5V, but you may not expose the I/O pins of the ESP32-C3 to voltages above 3.3V.

5

rotary knob
rotary knob1347×807 142 KB

As you can see, there is just a ribbon cable available for interfacing. No 3.3V here.
image
image800×800 48 KB

6

By the way, don't understand why a such trivial, pure resisitive splitter won't be enough. As far as I know the communication from 506F to ESP32 is unidirectional.

splitter
splitter1920×1057 169 KB

7

Such a divider is very commonly used, but the resistances are typically about 1K and 2K, to lessen the RC rounding of signal edges. That will work only if the sensor output is capable of driving 3K without voltage droop.

8

The input pins on ESP32 (or any other Arduino boards) usually have reasonably high input impedance thus thie driving current is almost negligible. Does it have that that big capacitance so that the digital signal might distort in a way to become unusable? 2.5K is a lot, it means 2 mA constant consumption.

9

If you want to use a voltage divider as a logic level converter, the question is whether the sensor output can drive a low enough impedance, to avoid output signal distortion by load capacitance.

To decide that, you must also know and take into account the sensor output data rate.

What is the communications protocol? Have you ever used this sensor successfully, on any platform?

10

ZAC wire, never ever have used, even seen it.

11

A good place to start would be with a 5V Arduino, and get the sensor working, before worrying about interfacing to a 3.3V MCU.

You may have to write library code to handle the ZAC Wire protocol, but it is possible that someone already has, for Arduino.

12

Yes, there is a complete library already available.
I have some unused Arduino Nano controllers (classic 5V version), it might be indeed a good place to try.

13

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.