6 📐 Calibration

"A miss is as good as a mile." 🎯

Preparations

1. all the servos are connected to the correct sockets on the board in the correct orientation

2. don't attach the legs to the servos.

   1. The reason is when the robot is powered, the legs could move into each other or collide with the body. The servos may be damaged after getting stuck for a long time.

3. long-press the battery power button

4. the blue and yellow LEDs on the board indicate the board is powered on

Enter the calibration mode

You must install the head and leg components on the servo's output shaft gear during calibration. No screws are required, but you must enter the calibration mode before installation.

There are five methods to enter the calibration state:

• Long-press the battery and boot up the robot with one side up. It will enter the calibration state automatically. This feature is available for all robots manufactured after 2022.

• Use the mobile app Petoi to enter the calibration panel.

• Use Joint Calibrator in Petoi Desktop App :

  • If you have already connected the robot and computer with a serial port, It will enter the calibration state automatically when you click the " Joint Calibrator" button

  • Click the "Calibrate" button in the calibrator interface

• In the serial monitor of Arduino IDE, enter the serial command "c"

• Press the calibrating button (3,3 - the 3rd row and 3rd column) on the infrared remote.

Install the head

In the calibrated neutral state, place the head as close to the central axis as possible and insert its servo shaft into the servo arm of the neck.

Press down on the head so it is firmly attached to the neck.

Install the legs

Insert the upper legs and the lower legs into the output teeth of the servos while Bittle is powered on and in the neutral position. When inserting, try to keep the torso, upper leg, and lower leg at right angles with each other as much as possible. Pay attention not to install the lower leg backward (the correct orientation is shown in the picture below).

Calibrate the head and the legs

To calibrate the head, adjust the neck servo angle in the app until the head is straight forward. If the servo angle reaches the limit but the head is still not straight, you should return the servo to the neutral position, and reattach the head closer to the forward position.

To calibrate the legs, place the L-shaped ruler included in the kit next to a leg, as shown in the picture below. (Note: the picture below shows the screws in the joints. You may put on the screws, but you should NOT tighten them before the calibration is finished.)

Adjust the servo angles of the corresponding servo in the app until the reference features on the leg (i.e., the screw holes on the joints, the "muscle line" on the upper leg, and the triangular hollow space on the lower leg) are all aligned with the openings on the L-shaped ruler. Repeat this process for all four legs.

Once calibration is finished, use the provided flat-head screws to secure all the shoulder and elbow joints.

For more details, you can also read the calibration guides below:

• Petoi mobile app.
• Petoi Desktop App.
• Petoi Arduino IDE.

For more details, please refer to the Joint Calibration in the Doc Center.