Tutorials

Electronics Fundamentals: the rover

last updated: 21/09/18

Introduction

We need hardware :), so each student builds his own rover. The rover is WLAN controlled by a computer or phone.

rover handy

Bill of materials (BOM)

Mechanics

Most parts have to be mounted in the right direction. It is frustrating to unmount parts that are not mounted the right way, so stay concentrated and look twice at the pictures.

bom

motor mount

wheel mount frontwheel

battery holder battery holder bottom

PCB assembling and soldering

How to solder

There are many sites and videos on the net, so I will not reinvent the wheel. Here is a link, explaining soldering: https://www.sciencebuddies.org/science-fair-projects/references/how-to-solder Read the 6 Tabs carefully an then just do it :). Exercise is the best teacher.

Respect the following seven points:

  1. Clean always your tip of the soldering iron by wiping on a damp sponge or cleaning wool.
  2. Your PCB has to be free from dirt.
  3. Heat the connection (copper pad and lead from the component) with the tip of the iron for a few seconds before! applying the solder wire (a big pad e.g. GND plane needs more time to heat up!)
  4. Keep the iron tip on the connection as the solder is applied and use just enough solder to form good connection (see images on link above).
  5. Remove the tip from the connection as soon as the solder has flowed. Remove first the solder and then the iron. The whole process should take just a few seconds, so don't overheat the connection.
  6. Don't move the connection while the solder is cooling!
  7. Inspect the joint closely and if the connection looks bad, reheat it and try again.

Soldering

pcb pcb populated

mhetlive 1 mhetlive 2

Connecting the motors

motorsoldering motorwiring

motor wires motor wires with tube

Connecting the battery holder and the switch

Programming the ESP32 with Arduino

Installing Arduino

Download the latest Arduino software from Arduino.cc and extract the compressed folder. You can do this on a USB Stick. Now switch to the Arduino folder and create a folder with the name portable inside the Arduino folder. A portable installation allows to carry around your personal set of sketches, cores and libraries, to be used on any computer without affecting it with your files (see here).

To be able to use Arduino with ESP32 we add the ESP32 framework simply by adding a text line to to "File > Preferences > Additional Boards Manager URLs:". Enter the string

https://dl.espressif.com/dl/package_esp32_dev_index.json

into Additional Board Manager URLs: field. You can add multiple URLs, separating them with commas. So we also add the strings

http://arduino.esp8266.com/stable/package_esp8266com_index.json

to be able to use ESP8266 devices. Now open Boards Manager from Tools > Board: > Boards Manager..., scroll down and install ESP32 and ESP8266 platform.

To use later Teensy Boards we download Teensyduino from the pjrc homepage and follow the instructions on this page to install it..

After the installation we select our ESP32 board MH ET LIVE ESP32MiniKit from Tools > Board).

Programming the ESP32

In Arduino the C or C++ code files are named "sketch" have the extension .ino and must be contained in a folder with the same name (without .ino).

Download the file space_mining_rover_esp32.ino to your portable/sketchbook folder and open it in Arduino (File > Open). Arduino will create the folder for you (OK).

Change your SSID and Password in the sketch:

    const char *ssid = "btsiot01";  // AP settings
    const char *password = "btsiot01"; //password must have more than 7 characters!!

Now we click on the Arduino Upload button arrow to the right to compile and upload our sketch.

Downloads

Finish

First Test

rover url