The heads arm coil bhaves as a galvanometer.

However its behavior is not totally linear. Thus the minutes ticks could be a little unprecise...

A calibration procedure is needed!

I have choosen to calibrate the minutes every 5min. It meens that a multi linear curve is applied to fine tune the PWM value applied to the coil.

Once again you can use the PC application to interactively enter these calibration values. You will have to enter 5 values (00:00, 00/15, 00:30, 00:45, 01:00)

• check the box  

• you can now move the horizontal scroll bar 

• positon the arm to 00:00; 00:15 ; 00:30 ; 00:45 ; 01:00 and each time write the value in the adhoc text box (example for 00:30)

• save these values in eeprom 

Your coil arm is now calibrated!