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Q1: How can we know the servo is damaged?

A1: In Servo Test step, if the servo rocker arm shake, get stuck or can not rotate smoothly, with an abnormal sound, we can judge it as a damaged one.

Q2: Why the Sloth reboots in running?


       i.          If you use the battery with protection board, the battery protection board will lower the voltage when the output current is higher than the standard, thus the sloth will reboot. You can remove the protection board on the battery’s cathode, be careful to operate. Or choose the battery without protection board.

      ii.          If the Sloth is in lower power, rebooting will happen too. Use a fully-charged battery (Supply voltage: 6V-8.4V)

     iii.          It coulbe be the servos are lacking for power. Open the program and go to Line 12,13. “vel” is the servos rotating speed in “initialization or moving forward”; “vel_Back” is the servos rotating speed in “moving backward”; “delay_Forward”, “delay_Back” are the delays between two moving forward loops and moving backward loops.

1)     If rebooting happens in moving forward actions, you can decrease the value of “vel” or/ and increase the value of “delay_Forward”. For example, decrease “vel” value to 10, and increase “delay_Forward” to 1500.

2)     If rebooting happens in mocing backward actions, you can decrease “vel_Back” or/ and increase “delay_Backward”. For instance, decrease “vel_Back” to 8, and increase “delay_Backward” to 1500. You can adjust to a proper value as you want. Then click Upload.

If the rebooting still happens after the above operations, you can try the following steps to calibrate in condition that the values of array_cal[1] and array_cal[3] are roughly the same.

Modify the line 21, 22 to “{0,-20,0,-40}, {30,-20,50,-40},    ”

And line 24, 25 to “{0,40,0,20},{-30,40,-30,20},    ” as shown below:

Then exchange “10” in line 120 and “12” in line 122 as shown below. Click Upload.

Q3: Sloth walks too slowly. How to solve this?

A3This is caused by the Sloth self-weight and the limited servos power. You can try to replace如the servo provided in the kit by more powerful servos. Refer to calibration part of iii under A2 in Q&A, but adjust in the opposite way.


In this manual, having learned the related components for building the robot kit, you’ve gone through the assembly of the mechanical parts and electrical modules with the knowledge of Arduino as well as a brief introduction of the key parts like servo, ultrasonic, etc. Also you’ve got a lot of software and coding, which lays a solid foundation for your futrue journey of exloring open-source field.

The SunFounder DIY 4-DOF Robot Kit is not only a toy, but more a meaningful development kit for Arduino. After all the study and hands-on practice of the kit, you should have a better understanding of Aduino. Now, get started to make better work!

Copyright Notice

All contents including but not limited to texts, images, and code in this manual are owned by the SunFounder Company. You should only use it for personal study, investigation, enjoyment, or other non-commercial or nonprofit purposes, under the related regulations and copyrights laws, without infringing the legal rights of the author and relevant right holders. For any individual or organization that uses these for commercial profit without permission, the Company reserves the right to take legal action.