jaygit/pirover

This file is a documentation of the pirover project

List of Hardware components

• Raspberry pi Zero W ![Raspberry pi zero w 50] (https://cdn.shopify.com/s/files/1/0176/3274/products/raspberry-pi-zero-w-raspberry-pi-sc0020-14879106433086_700x.jpg?v=1646233385)
• RaspiRobot V3f ![RaspiRobot V3f] (https://cdn-shop.adafruit.com/970x728/1940-00.jpg)
• LIPO 18650 3.7V
• Motors and Wheels and Frame
• Servo Mounting unit ![acrylic mounting unit] (https://imgaz.staticbg.com/images/oaupload/banggood/images/D4/4E/9a72eaba-dc09-4fdf-bdbd-9c72458607fb.jpg.webp)
• SG90 Servos x 3
• VL53L0X Time of Flight sensor
• 18650 3x batter holder
• Pan&tilt mechanism
• tiny breadboard
• nylon standoff and screw
• brass standoffs
• nightvision camera
• proximity sensor x2
• jst connectors
• jumperwires
• Magnifying glass with lamp
• Helping hand
• nylon ties

Python

The python code has been taken from the followng libraries

1. Simon Monks python library rrb3
2. Hands-On MQTT programming with Python by by Gaston C. Hillar
3. Building a streaming library with picamera

Node-Red

Node-red was used to develop an interface for controlling the car and camera. It was also used as a means of being able to see the streaming video of the rover

MQTT

Finally, I wanted to use MQTT to pass messages to the rover and get telemetry data from the rover.

Hardware considerations

Using the time of flight sensor (VL53L0X)

Initially I tried the traditional HC-SR04. However the drawback with this was that it ultrsound is not the best wave to bounce off fabric. So Couches and curtans were not detected very well.

I had to add the proximity sensor to overcome when theultrasonic sensor was not very good at this. This added further logic to the code.

The time-of-flight sensors have become quite cheap. The one that I am using does not have a big range. However because the rover is not going at speed anywhere it was easy to incorporate the VL53L0X into the design.

I might be able to remove the proximity sensor once I am have been able to code the time-of-flight sensor better.

I am using pimoroni's VL53L0X library.

I am using 3 of the 18650 batteries, although one should have been sufficient. This allows me to play a little longer.

Servos (SG90)

I have not had much success with controlling the jitter on the servos. I used a variety of libraris to experiment with controlling the jitter. My idea of electricity and PWM is very basic. So the controls for the camera servos ae not very good.

Node-red mobile interface