Plotclock改(kai)

This is a remix of plotclock(https://www.thingiverse.com/thing:248009).

https://youtu.be/3VeTzbk-lLA

Parts other than prints
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* ATOM Lite (1 pce.)
* universal PCB
* pin header
* MG90S servo (3 pcs.)
* magnetic drawing board 106x76mm (1 pce.)
(I used : https://ja.aliexpress.com/item/1005002280761444.html)
* M2.1x10mm flat head tapping screws (11 pcs.)
* M3x10mm tapping screws (8 pcs.)
* M2.5x6mm screws (3 pcs.)
* M3x10mm screws (4 pcs.)
* M3x30mm screws (2 pcs.)
* M3 washers (4 pcs.)
* M3 nats (10 pcs.)

How to operate
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Start the Arduino and display the serial monitor.
For the first time, start the Arduino in Calibration mode.

First, calibrate the arm.
Remove arm_r (MG90S) and arm_l (MG90S).

Enter "l" to calibrate the left servo.
Place calibration_plate on the left side servo.
The position offset 20deg from directly above to the left is 0deg, and 1 memory is 10deg.
Set 0de