SunFounder PiArm User manual

Piarm
Release 1.0
www.sunfounder.com
Mar 31, 2022

CONTENTS
1 Component List and Assembly Instructions 3
2 Hardware Introduction 5
2.1 Arm .................................................... 5
2.2 Shovel Bucket .............................................. 8
2.3 Hanging Clip ............................................... 12
2.4 Electromagnet .............................................. 16
2.5 Dual Joystick Module .......................................... 18
2.6 About Robot HAT ............................................ 21
3 Play with Ezblock 23
3.1 Quick Guide on Ezblock ......................................... 23
3.2 Assemble and Test 3 EoATs ....................................... 25
3.3 Sound Effects ............................................... 33
3.4 Dual Joystick Module .......................................... 37
3.5 Remote Control ............................................. 49
3.6 Coordinate Mode ............................................. 65
3.7 Memory Function ............................................ 69
3.8 GAME - Catching Dolls ......................................... 73
3.9 GAME - Iron Collection ......................................... 81
4 Play with Python 89
4.1 Quick Guide on Python ......................................... 89
4.2 Assemble and Test 3 EoATs ....................................... 110
4.3 Sound Effects ............................................... 112
4.4 Dual Joystick Module Control ...................................... 114
4.5 Keyboard Control ............................................ 121
4.6 Coordinate Mode ............................................. 129
4.7 Memory function ............................................. 132
4.8 GAME - Catching Dolls ......................................... 135
4.9 GAME - Iron Collection ......................................... 138
5 Appendix 143
5.1 I2C Configuration ............................................ 143
5.2 Remote Desktop ............................................. 145
5.3 About the Battery ............................................ 154
6 Thank You 157
7 Copyright Notice 159
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Piarm, Release 1.0
Thank you for choosing our PiArm.
PiArm is a three-degree-of-freedom robotic arm for Raspberry Pi. It has 3 interchangeable parts - bucket, hanging clip
and solenoid - to help you perform different tasks.
In addition, PiArm offers both remote control and built-in dual joystick module control.
This tutorial includes several parts: device list, assembly guide, programming and appendices. The programming
section is divided into two chapters: Playing in Ezblock and Playing in Python, each of which allows you to make
PiArm work the way you want it to.
•Play with Ezblock
If you are new to programming, check out this chapter as it introduces Ezblock Studio, a block-based visual program-
ming software that allows you to make PiArm move and implement some interesting projects by simply dragging and
dropping blocks.
•Play with Python
If you prefer to program in a more popular programming language - python, you can refer to this section. The chapter
covers starting from burning the Raspberry Pi OS, to configuring the Raspberry Pi and finally getting the code running
to see the effects, even if you don’t have any Python foundation, you can get PiArm working quickly.
CONTENTS 1

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2 CONTENTS

CHAPTER
ONE
COMPONENT LIST AND ASSEMBLY INSTRUCTIONS
You need to check whether there are missing or damaged components according to the list first. If there are any
problems, please contact us and we will solve them as soon as possible.
Please follow the steps on the PDF to assemble.
Note:
1. Before assembling, you need to buy 2 18650 batteries and fully charge them, refer to About the Battery.
2. Robot HAT cannot charge the battery, so you need to buy a battery charger at the same time.
•PiArm Assembly Instructions (.pdf)
Warning: If the kit you received includes a clear Robot HAT Case, please do not mount it so as not to affect the
PiArm left and right rotation range.
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CHAPTER
TWO
HARDWARE INTRODUCTION
2.1 Arm
PiArm’s arm can be controlled in two ways: Angle Mode and Coordinate Mode.
•Angle Mode: Writes a certain angle to the three servos on the arm, thus rotating the arm to a specific position.
•Coordinate Mode: Create a spatial right-angle coordinate system for the arm and set the control point. Set the
coordinates of the control point so that the arm can reach a specific position.
2.1.1 Angle Mode
The arm has three servos to control its up and down, left and right, and front and back. We use , and to represent their
rotation angles, as shown below.
•(alpha): represents the front-to-back rotation angle of the arm, due to the limitation of the structure, the
recommended rotation range is: -30 ~ 60.
•(beta): represents the up and down rotation angle of the arm, due to the limitation of the structure, the
recommended rotation range is: -60 ~ 30.
•(gamma): represents the left and right rotation angle of the arm, the range is: -90 ~ 90.
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2.1.2 Coordinate Mode
PiArm has a spatial rectangular coordinate system with its origin located at the center of the output axis of the servos
on both sides. The Control Point is located at the top of the arm and is scaled in millimeters. In the initial state, the
coordinates of the Control Point are (0, 80, 80).
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It is important to note that the arm length of PiArm is finite, and if the coordinate values are set beyond the limits of
its mechanical motion, PiArm will rotate to an unpredictable position.
In other words, the total arm length of PiArm is 160 mm, which means that the limit value of the control points moving
along the Y-axis should be between (0,0,0) and (0,160,0). However, due to the limitations of the structure itself, the
range of movement should be much smaller than this.
• The recommended range for the X coordinate is -80 ~ 80.
• The recommended range for Y coordinate is 30 ~ 130.
• The recommended range for Z coordinate is 0 ~ 80.
2.1. Arm 7

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2.2 Shovel Bucket
Assembling the Shovel Bucket
Assemble the Shovel Bucket as shown below.
Note: In step 2 you need to insert the servo into P11 for zeroing before inserting the D3 plate into the servo shaft in a
vertical orientation.
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Assemble the Shovel Bucket to the end of the PiArm with M2x4 screws.
2.2. Shovel Bucket 9

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The Shovel Bucket has a rotation range of -90 ~ 60.
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Use range
Can’t dig water, can be used to dig sand and gravel.
2.2. Shovel Bucket 11

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2.3 Hanging Clip
Assembly
Assemble the Hanging Clip as shown below.
Note: Note that in step 3 you need to insert the servo into the P11 for zeroing before inserting the D1 plate into the
servo shaft in a vertical orientation.
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Attach the Hanging Clip to the end of the PiArm with the M2x4 screw.
2.3. Hanging Clip 13

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The angle range of the Hanging Clip is 0-90°.
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Using range
• The weight of the clamped object should be less than 150g.
• The recommended height of the object to be clamped should be less than 4cm, width less than 8.5cm.
• Slender objects need to find the right angle to clip up.
Translated with www.DeepL.com/Translator (free version)
2.3. Hanging Clip 15

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2.4 Electromagnet
Assembly
Assemble the electromagnet module according to the diagram below.
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