This can be useful, if you have this motor and you don't want to open it to install an NTC.
So, Cromotor v2 has a spare Hall-sensor set in the stator core close to the windings, that is normally unused. Between the output of the hall-sensor and the GND there is a reversed diode embedded inside the chip and it can be utilized to measure the temperature. This diode is for output protection or just a parasitic diode, it does not matter. The voltage of the diode is temperature-dependent like an NTC, it has about a constant -2mV/degrees coefficient. This is smaller than of a 10k NTC that is usually applied, but the voltage can be measured with a microcontroller if you have the tools.
Also as I see on this link, CA V3 temperature measurement has a "Linear Type" temp sensor feature that is probably exactly what we need: http://www.ebikes.ca/store/store_CAV3.php
The offset and the scale must be set up, if the scale can be set to around 500 Deg/V in the CA, then it is ok. (I don't have a CA)
How to connect the sensor?
Connect the GND pin of an unused hall-sensor to 5V via a pull-up resistor, and connect its output to GND. Measure the voltage of the signal between the pull-up resistor and the sensor. An RC filter is useful to filter the noise and to protect the microcontroller (it is probably on CA also, I guess).
Here is the connection diagram:
For setting up, you can do a 1 point calibration to find the offset and suppose the -2mV/deg coeff, or a 2 point calibration to find both the offset and the exact coefficient. (measure the ambient temp with a thermometer and the diode voltage at 2 different temperatures)
So, Cromotor v2 has a spare Hall-sensor set in the stator core close to the windings, that is normally unused. Between the output of the hall-sensor and the GND there is a reversed diode embedded inside the chip and it can be utilized to measure the temperature. This diode is for output protection or just a parasitic diode, it does not matter. The voltage of the diode is temperature-dependent like an NTC, it has about a constant -2mV/degrees coefficient. This is smaller than of a 10k NTC that is usually applied, but the voltage can be measured with a microcontroller if you have the tools.
Also as I see on this link, CA V3 temperature measurement has a "Linear Type" temp sensor feature that is probably exactly what we need: http://www.ebikes.ca/store/store_CAV3.php
The offset and the scale must be set up, if the scale can be set to around 500 Deg/V in the CA, then it is ok. (I don't have a CA)
How to connect the sensor?
Connect the GND pin of an unused hall-sensor to 5V via a pull-up resistor, and connect its output to GND. Measure the voltage of the signal between the pull-up resistor and the sensor. An RC filter is useful to filter the noise and to protect the microcontroller (it is probably on CA also, I guess).
Here is the connection diagram:
For setting up, you can do a 1 point calibration to find the offset and suppose the -2mV/deg coeff, or a 2 point calibration to find both the offset and the exact coefficient. (measure the ambient temp with a thermometer and the diode voltage at 2 different temperatures)
