SEN0256 Temperature probe not reading correctly
Toby.Cotter 2023-02-01 07:24:13 1148 Views11 Replies I have a SEN0256 probe connected to a 5v Arduino Uno. When I point the probe at my forehead, I am reading a temperature of 62.0 C. I should be getting a reading of 37C. I copied the conversion formula straight from the DFRobot wiki page. Any idea on why I am reading the wrong value?
void setup() {
Serial.begin(115200);
}
void loop() {
unsigned int ADC_Value = analogRead(A5);
float i=((double)ADC_Value*450/614.4-70);
Serial.print(i);
Serial.println();
delay(500);
}
Thanks for the information.Keep sharinglike this.
coreball
Chase.Peck Hope it can help!
coreball
According to the datasheet, I have connected the power supply to the respective pins ( Red – 24VDC , Black -GND , Yellow – Output , Sheield – GND ). After powering on, I am receiving a sensor output of 0. 8V DC.
Based on the sensor specifications, if I calculate the temperature with respect to the output voltage, it indicates 70 degrees Celsius.
However, the actual room temperature is only around 20 to 23 degrees Celsius.
kindly request your assistance in resolving this issue.
silambarasan.Bala Changing from 450 to 340 solved the issue. Thank you for your help!!!
Toby.Cotter I have my Arduino powered by 9v. I have the temp sensor connected to A3 and the code also uses A3. I am still reading my body temperature as 62.0 C. I am thinking the formula below is incorrect or my probe is malfunctioning. Any ideas?
unsigned int ADC_Value = analogRead(A3);
float i=((double)ADC_Value*450/614.4-70);
From the code above:
ADC_Value = 180
i = 61.84
Thank you for your help
Toby.Cotter Hi
After troubleshooting with our PM, I'm happy to tell you we find the root cause!
There is a mistake in our Wiki code, please kindly change the 450 here to 340, and it will be fine. The wiki page will be updated soon. Thank you for your information.
And Very Sorry for all the inconvenience!
Hope it can help!
I think, some corrections must be done in the wiki: https://wiki.dfrobot.com/TS01_IR_Thermal_Sensor_(0-3V)_SKU_SEN0256
The diagram shows that the yellow wire of the sensor is connected to A5. But the code reads the analog value from the pin A3.
unsigned int ADC_Value = analogRead(A3);
bidrohini.bidrohini Hi
Thank you for your information! We have corrected this error on Wiki after your message.
Sorry for the misleading example code.
Hi
Sorry for the inconvenience.
The reason why an external power supply is recommended is that USB port can only support voltage up to 5v, while the working voltage of this sensor is 5 - 24v. An 9V external power supply is recommended for higher accuracy.
If the data remain incorrect after using an power supply, we will discuss with other PM about this issue.
Hope it can help.
Tonny12138 Attached is a photo of my setup. The Arduino is powered by USB, but the USB is a powered hub so I think it should be ok. I have also tried with a 2nd Arduino board and got the same issue.
Thanks
Toby.Cotter Hi
Sorry for the inconvenience.
Could you please share a photo of how you connected the wire? including the way you provide the power supply.
If you are using a USB cable for your power supply, could you please switch it to an external dc power supply? It could be an issue related to the input voltage.
Also, if it is possible, trying another development board and measuring something else could be a good way to diagnose the problem.
If you need further support, please feel free to contact our Tech support team via email.
Hope it can help!
Tonny12138 