Lesen vom Thun T13 Drehmomentsensor nicht möglich( Unable to get reading from Thun T13 Torque Sensor )

[shashankh]

Hi,
I'm new to the world of EBikes and have only a bit of experience in development of electronics. I want to get the readings of a Thun T13 torque sensor on an ESP32 microcontroller (or Arduino). The sensor will supposedly generate output from 1.5V to 3.3V according to the torque applied as per the datasheet. But I'm getting 3.3V on all the pins of the torque sensor.
I have seen the datasheet of the Thun T13 torque sensor which shows 6 pins with power, torque and rotation pins - I uploaded the datasheet for reference.

I tried analogRead but it doesn't give any output as expected. I have connected the torque signal from the torque sensor to an analog pin of the ESP32 and done analogRead but I get a constant value (read from serial monitor) even after turning the torque sensor.

Here is the setup with an RPS set at 12V:

RPS- positive to torque sensor positive power pin and GND of RPS to torque sensor GND and also to ESP32 GND. Then took the torque sensor signal and set it on the ESP32 ADC pin where I read the signal with analogRead. (tried with ESP32 pins 2, 4, 34, and 36. All have same result -> 0 with no change after giving torque)

Here is the weird reading I get on DMM with different conditions:
No torque on sensor : 3.3V
applying torque clockwise and anticlockwise : 3.3V
So no change in the voltage from signal with movement. I have no idea what the protocol would be after this test. Could it be a defect of the sensor or anything wrong from my side?

I tried connecting it to a USB logic analyzer as well and got no change in the voltage reading as well
I am not sure whether the connections I did are proper with the logic analyzer, but I connected the power supply from the RPS as usual to the torque sensor power pins and took the GND from torque sensor and connected it to the GND of the logic analyzer . The torque signal from the sensor connected to channel 1 of the logic analyzer.
Result == No change or pulses viewed

My questions are:

1. What are the connections to link an Arduino with the torque sensor? Any datasheet or manual would be helpful as I have scourged the internet but found no guide. Could I directly connect the pins to the Arduino and get the readings? Am I doing something wrong with the connections?

2. Would any additional circuitry be required to measure the torque?

3. Would you recommend any other tests or methods to get the data from the torque sensor?

4. I would appreciate any assistance in any alternate known torque sensor which is confirmed to work with a microcontroller to run on an EBike. Any links or names would be nice

I have also created a discussion on Arduino forum here
Arduino with torque sensor connection for E-Bike

Thanks for your time,
Best regards,
Shashank

 

[Hochsitzcola]

Did you measure the signals with the DMM with no ESP32 connected?
If not, try this first. Just connect GND and the 12V power supply to the sensor.
Measure between GND and Speed while turning the pedals very slowly: the signal must jump between 0V and 5V.
Measure between GND and Torque and apply torque on the pedal with a blocked rear wheel: The singal must rise with the rising force on the pedal. (Important: you have to test with installed chain and blocked rear wheel!)

If the signals aren't as described, the sensor is defective.

regards
hochsitzcola

 

[shashankh]

Did you measure the signals with the DMM with no ESP32 connected?
If not, try this first. Just connect GND and the 12V power supply to the sensor.
Measure between GND and Speed while turning the pedals very slowly: the signal must jump between 0V and 5V.
Measure between GND and Torque and apply torque on the pedal with a blocked rear wheel: The singal must rise with the rising force on the pedal. (Important: you have to test with installed chain and blocked rear wheel!)

If the signals aren't as described, the sensor is defective.

regards
hochsitzcola

Yes I have done that, same issue with no change in voltage even after rotating the sensor. I have 2 sensors with me, but weird thing is one torque sensor shows 3.3V constantly even with changing speed on the sensor and while exerting no force( as explained in my post). The other torque sensor shows a constant 0.2V on same pins with same configuration even while exerting no force or putting force on it (no ESP connected, directly measured from DMM).
So both sensors even though identical have different output voltages which is confusing, even though datasheet says not to be.

 

[Swaraj]

Hi, this is Swaraj and I am currently working on an E-Bike which needs torque sensor to be fitted to bottom bracket. Can you tell me from where did you get the T13 torque speed sensor? It would be really helpful if you can provide any source to buy this sensor.

 

[shashankh]

Hi, this is Swaraj and I am currently working on an E-Bike which needs torque sensor to be fitted to bottom bracket. Can you tell me from where did you get the T13 torque speed sensor? It would be really helpful if you can provide any source to buy this sensor.

Hi, I bought it at Kaufland (check their website)

 

[Hochsitzcola]

where did you get the T13 torque speed sensor?

I've ordered at PhoebeLiu EV parts:
torque sensor - Shop Cheap torque sensor from China torque sensor Suppliers at PHOEBELIU EV PARTS&tools Store on Aliexpress.com

The T13 is not a Thun product....

interessant, daß sich Kaufland.de zu einem deutschen AliExpress entwickelt
T13 Speed and Torque Sensor für E-Bike Pedelec Elektrofahrrad (73 x 152mm)
Der Verkäufer dort hat die gleiche Firmenadresse in Berlin, wie eRider, die offiziell als Hersteller und Patentinhaber dieses Sensors auftreten und den Sensor bei PhoebeLiu als nicht authorisiert bezeichnen, was auch immer das bedeutet....
Wenn man einen eRider-Katalog bestellen will, landet man bei einer portapower-EMail-Adresse. Merkwürdiges Geflecht...

Gruß
hochsitzcola