Introduction: CHOOM [FINAL] Follower Robot Circuit Connection, Building Leader Robot

About: Hi, I'm Eunchan Park from S.Korea. I have 3 missions Making Happy Things, Sharing How To Make Happy Things, Copying Happy Things Maker for the world's Happiness In order to pursue my mission, I have a big goal…

In this episode, I will make the circuit board and a stand for the robot and upload the Arduino code.

And then, we will make a leader robot, program and make them move!

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Step 1: PCA9685

We are going to use a pair of this servo board. To use the servo board together, we need to change the address by soldering one point. Put all the circuits together and connect wires like this picture.

Step 2: Soldering for Different ID

If you already followed previous episodes, this step will be easy for you. We don’t need to use cables to connect the pair of servo board. I just soldered them together.

By the way, I was trying to solder with lead-free thread. It is somehow more difficult than a typical lead.

Step 3: Board Connection

At last, it’s time to connect the board to the robot. The Left board is for the upper body, and the other board is for the legs. I put the numbers on the board and the robot. Connect them carefully.

You may feel that there are so many cables, and it is difficult to manage them. That is one of why I like smart actuators like Robotis Motor.

Step 4: A Robot Stand

We are going to make a stand for the robot. You will find the link when you see the description below. Please print and attach them to a kitchen towel holder.

Step 5: Uploading Arduino Code

All we have to do is to download a new code into the Arduino. I also put a link in the description. The code makes all motors go to the center position and stay. You can adjust your robot. When the other robot sends data, this robot will move.

Step 6: Making Mater Robot

From this chapter, I will introduce how I made the leg part of the leader robot. There is a problem with Arduino not having enough ADC channels. I will show you how I managed it.

Step 7: The Goal of Master Robot

Here's the goal of this chapter. I already managed to move 8 motors for the arms with 8 potentiometers. This time, I will use 12 more motors and potentiometers.

Step 8: Problem

But there's a problem with the Arduino. Arduino only has 8 ADC channels. As you already know, Arduino uses ADC to read the angle of the potentiometers. How can you read 20 potentiometer's value with the limited number of ADC channels?

Step 9: Solution

I tried to look for a solution to this problem, and I've found a practical solution at last. With this multiplexer, I can get many ADC values in order.

How does it work? It is very simple. we choose one channel by one channel of potentiometers. The only thing I need to do is let the multiplexer know what channel I want to read. then, the multiplexer will connect the output line to the channel I wanted.

Since the 74hc4067 board has 16 channels, I need to use 2 pieces of the board.

Step 10: Schematic

Here's a schematic of the concept. All the potentiometers are connected to the multiplexer. And there are S0 to S3 pin, which allows you to select the channel by setting the pin based on binary code. For example, if you want to select channel 8, you need to set S3, S2, S1, S0 as 1 0 0 0. it means number 8 in a binary number. Then, the SIG pin will be connected to the pin you wanted to connect to.

Here's also another schematic looks more like an engineer's way. I needed to put all the components on a board and solder them properly. It was kind of tedious to solder one by one. I could've done with manually, but I didn't want to. That's when I decided to make a PCB board.

Step 11: PCB Board

I drew a simple PCB board on EasyEDA, a web-based design tool. You can use this tool without any schematic. It gives you a lot of pre-made PCB components, and with them, you can just put the elements and route one manually.

Once you have done with a PCB file, you can simply order the PCB at a pretty low price. JLCPCB provides manufacturing the PCB with only 6.1 dollars. I got 10 PCB board.

If you want to use my design, link in the description.

it turned out that I designed it in the wrong way. I didn't take the volume into account. Those two boards are colliding with each other. I had to redesign the PCB again. The link is here.

you can just download my design and order the PCB from JLCPCB. In this video, I just soldered them by force. it sometimes happens haha.

Step 12: Hardware Frame Design

I am using Fusion360 from Autodesk. If you want to do your awesome project, consider using the Fusion360.

This shows how I designed the robot.

Step 13: ​3d Printing

If you just want to use the STL file for printing, the link is on the description. Please download the 3d files from Thingiverse. I usually print them with a 5% infill with 2.4mm thick perimeter.

Step 14: Assembly

please take a look at the video and follow the order. If you are confused, please take a look at the schematic.

Step 15: ​Arduino Programming

I know you would know how to upload the code to the Arduino. here's the link of the leader robot. Download the source code, open the Arduino IDE, select arduino nano old bootloader and click the upload button.

Step 16: ​Test

please take a look at the servo motors from the follower robot if there's a motor that stuck in the frame which constantly gets powered. it will break you motor

I hope you finish your project with this guide. thank you for watching and following the video instruction. I am sorry again for this delay.
Have a nice day and see you again!

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