- Remote control

Circuit

This section has been pre-worked during my Input devices and Embedded Networking and Communications assignments.

Components:

- Microcontroller board:
1x Vehicle-RemoteControl board ,whose documentation is in the next section

- Input devices:

The input devices I used to control the movements of the vehicle were Joysticks cause with them I can give direction and also control the speed depending on the percentage in which it is pressed.

2x Grove - Thumb Joystick v1.1: this is a 4 pins Joystick:

- Wireless communication:
1x nRF24 module: this one has the antenna on board; I have also replaced the pin header to adapt it to me needs/idea:

- Power:

1x UR18650 Li-Ion Battery 2600mAh 3.7V: a single-cell Lithium-Ion battery, with its battery holder and HW-168 charging module:

1x On/Off switch:

Vehicle-RemoteControl board

Requirements, considerations and component selection:

It’s worth mentioning first that I wanted all of the boards for my final project to be double sided.

Since I need three basic movements (X-Y and rotational movements) I used two Joysticks.

- I used an ATtiny1614 microcontroller cause it has the necessary pins and memory for this application.

Image taken from SpenceKonde.

- I used a nRF24 module for communication, then I have arranged pin headers for connecting this module.

- A 3.3V voltage regulator (since the nRF24 module works at 3.3V, the Joysticks can work at 3.3-5V, and also the ATtiny1614 can work at that voltage).

- 1uF capacitor for voltage stabilization.

- A LED (with a 499Ω resistor) to indicate that the board is getting energy.

- UPDI + VCC + GND connection for programming and powering my board.

- I have used the footprint of TH pin headers for the Joysticks.

- I have used TH pin headers to connect both sides of the boards, as a solution to not having rivets on hand.

Schematic

For electronics design I have used KiCad.

Even when I only need three inputs from the four that I can get from the Joysticks, I connected all of them so it could be used also for drones where besides Pitch, Roll and Jaw, you control Altitude.

If rivets are available, delete “Via3.3V1” and “ViaGND1” pins from Schematic and put the rivets instead in the Board layout.

Board layout

I used the front layer mainly for logical connections and the back layer for Power connections.

• Front side:
  

• Back side:
  

Eventually I have used “Add filled zones” as GND.

I have exported the images as SVG, then I prepared them using Inkscape and GIMP and exported them as PNG with DPI=1500.

Milling

I have manufactured the by milling.

Images:

I have milled the front side first, where I cut the outline:

• Traces:
  
• Outline:
  

Eventually I milled the back side, where I drilled the holes:

• Traces:
  
• Holes:
  

Afterwards I have generated the g-code using FabModules.

Milling process:

- The milling machine I used was the Roland MonoFab SRM-20.
- The tool I used was a V-bit 0.2-0.5mm.
- The double sided PCB was FR1.

• Front side:
  

• Back side:
  

Soldering

List of Components:

Qty	Component
1	ATtiny1614 microcontroller
1	LM3480-3.3v voltage regulator
1	1uF capacitor
1	499Ω resistor
1	LED
19	Single row right-angle male pin header
-	Cables

- I have added some FLUX SK 10 as a final protective layer..

Programming

Preparation

First settings

For the first time we need to add the MegaTinyCore to the Arduino IDE:

• Open the Arduino IDE.
• File > Preferences
• Paste the following link in Additional Boards Manager URLs: http://drazzy.com/package_drazzy.com_index.json
  
• Press OK
• Tools > Board > Boards Manager
• Search for _MegaTinyCore (by Spence Konde):
  

Connecting board to PC

For programming the board I used the USB and FTDI-UPDI adapter boards that I made during the Electronics production assignment:

Upload a Code

• To upload a code to the Board, we just need to use the following highlighted settings in the Arduino IDE:
  

• After selecting these options and when using the microcontroller by the first time, press Burn Bootloader to setup the Microcontroller; then you can just press the Upload button:
  

Download libraries:

Beforehand, it’s needed to install nRF24 (by TMRh20):

Code block

/* Made by Jefferson Sandoval for the Final project of FabAcademy 2021.
 *  
 * This is the official code for my Fab-RemoteControl of my Fab-OmniBot, a three-wheeled robot.
 * 
 * Uploaded to my own board that uses an ATtiny1614 microcontroller, a nRF24 radio transceiver 
 * module (as transmitter) and two joysticks.
 * 
 * Documentation:
 * http://fabacademy.org/2021/labs/kamplintfort/students/jefferson-sandoval/project/02_RemoteControl/
 */

//Libraries for Communication nRF24
#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

RF24 radio(4, 5); //Create radio object with and CE & CSN pins
const byte address[6] = "00111"; //Transmitter communication address

void setup() {
  radio.begin(); //Initialize radio object
  radio.setPALevel(RF24_PA_LOW); //Set radio range
  radio.openWritingPipe(address); //Set address to receiver
  radio.stopListening(); //Set module as transmitter
}

void loop() {
  int Values[3]; //Declare variable for data to send
  //int Values[4]; //When using the fourth Joystick reading

  //Read values from Joysticks and convert them to percentage.
  //I mapped the values from 270 to 750 cause that is the range of the Joysticks (instead of 0-1023).
  Values[0] = map(analogRead(0),270,750,-100,100); //Left and Right movement from Joystick_Right
  Values[1] = map(analogRead(1),270,750,-100,100); //Forward and Backward movement from Joystick_Right
  Values[2] = map(analogRead(7),270,750,-100,100); //Rotation movement from Joystick_Left
  //Values[3] = map(analogRead(6),270,750,-100,100); //This adds a fourth Axis, Y movement for Joystick_Left

  radio.write(&Values, sizeof(Values)); //Send array of Values to Receiver

  delay(100); //Send values every 0.1 seconds
}
}

Find a video of a simple test with this code here.

Frame

Design

For designing I used Fusion 360.

Since I was already made the Robot final design, making the remote control wasn’t a big deal:

• My Idea was having the horizontal movements on the right and rotation on the left, and I wanted to make them with engrave, but an engrave in the back side. As the acrylic is transparent I could se is from the other side and I looks nice to me, to the design had to be a mirror of the desired result:
  

Laser cutting

Further information about a laser cut process in my Computer controlled cutting assignment.

- For setting up the cutting I used RhinoCeros:

- The laser cutter I used was the Epilog Zing 24 - 30 Watts.
- Parameters used:
* Engrave: Speed: 100%, Power: 25%
* Cut: Speed: 40%, Power: 100%, Freq: 5000Hz

Note: I have cut the pieces together with the Robot frame.

Result:

Note: At this point I wasn’t removed the transparent film from the acrylic yet, that’s what looks burned from the laser cutter.

Assembly

At the end, it was just a matter of putting everything together. The frame was assembled using M3 bolts and nuts:

Files and references

KiCad project:
RemoteControlBoard.zip

Arduino Code:
RemoteControl.ino

2D Sketch:
RemoteControl.dxf

Datasheets:
- nRF24 Radio transceiver
- ATtiny1614 Microcontroller

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Last update: June 28, 2021