Calibrating the Grove High Temperature sensor
README.md is only for calibrating the probe and not the onboard sensor. So, this sensor comes with 2 thermometers:
- One which is for measuring room temperatures - that's found on the sensor's board.
- Another one which is for measuring temperatures between
+650 °C- it's the long metal wire. This is the one we're calibrating.
GrovePi continously read an analog port and print the values in the console. The analog port should be that of the
Grove High Temperature Sensor's.
Put the sensor's long wire into a cup of boiling/hot water and take note of the value that's printed in the
Raspberry Pi's console. At the same time, use a professional thermometer and measure the temperature and write it down.
Do the same thing with cold water.
We will now have 4 values written down in a note:
- 2 values that were printed in the
Raspberry Pi's console - these values correspond with the following 2 values.
- 2 values where the measurement unit is in
Celsius Degrees- measured with the professional thermometer.
Now, take the values that were measured with the professional thermometer and get them translated with the table provided in
90 °C corresponds to
Now, lets assign the following values to each of these variables:
i1= the translated value (from the table) we got when we measured the hot water w/ the professional thermometer.
i2= the translated value (from the table) we got when we measured the cold water w/ the professional thermometer.
o1= the value we got in our console when we measured the hot water w/ our GrovePi.
o2= the value we got in our console when we measured the cold water w/ our GrovePi.
Let's calculate an
offset and a
factor. We will insert the calculated values in our table (
First, lets calculated the
(o1 * i2 - i1 * o2) / (i2 - i1)
And then, we get to calculate the
factor. Use the
offset value for calculating the
(o1 - offset) / i1
thermocouple_table.json file and update the following values:
amp_offsetset the value we got for
offset- it's preferable to have up to 6-7 digits in precision.
amp_factorset the value we got for
factor- it's preferable to have up to 6-7 digits in precision.
Save the modifications.
It's going to use the newly updated values.