Cheap Arduino Car #2

I made some progress last nights while staying awake until 3-4 AM. I have tried NRF24L01 modules but without success. I have to order new ones, I have’t got any spares. They were working fine last year, I don’t know what happened. So, I decided to add Bluetooth Module (HC-06).

First of all, I was looking for Android App which will be the best for my purpose. Simple app which will be sending data to the car continuously! I didn’t find such an app for controlling car. I found some, but they were horrible, but good for testing. The app I downloaded has joystick and buttons like gamepad. The problem was in joystick. It was just like 8 buttons and the direction you moved with joystick the specific button was sent to the car ONCE. When I released the joystick some another character was sent to the car but also ONCE. That was problem. Why? Because when I lost connection between smartphone and HC-06 the car will still going in the last known direction and car easily run away and be damaged. And so it happened. It fell off the broke rear bumper. Glue, easy fix.

When the car was finished and working I started programming custom Android application. I wanted keep it simple. I added status bar with connect switch, voltage and device name and coefficients. Below the status bar were placed custom made „Analog Sticks“, one vertical, one horizontal giving me a range of -1.0 to +1.0 for better calculations. I will talk about the app itself in the part #3.

Cheap Arduino Car #1

Besides Smartwatch Journey and Quadruped Project there are several projects waiting to be finished.
I built FPV (First Person View) RC car controlled by Arduino last summer. It was easy to build but the main chassis wasn’t looking so good. So, I decided to rebuild it.

  • The main parts of the car was: chassis with steering and motor included from construction kit rc truck, 2 x 18650 old batteries, Arduino Pro Micro/Mini, nRF24L01 with attachable antena, TB6612FNG as motor driver. I added 1000TVL FPV camera and transmitter Eachine TS832 later. The controlls was just 4 buttons (FWD / REV, LEFT / RIGHT) and FPV receiver RC832 from Eachine as well. There was also some regulator which will be mentioned later. Voltage divider to measure voltage with Arduino.
  • Reasons why I wanted to rebuild it:
    • There wasn’t any space to put batteries inside chassis, the only way was to use 4xAA  batteries insertable to the bottom part, but that’s too weak and slow for me cuz 4xAA can provide olny 4.8V – 6V due to type. The batteries was placed on the top of chassis making bad behavior of the car.
    • Power management wasn’t solved very good. As I accelerated the car the FPV transmitter shuted down and didn’t have enought power. I had to use another 600mA battery but it was drained in 15 minutes.
  • What I made new or added:
    • 3D-printed chassis
    • Old steering was replaced by servo motor steering with L7806CV voltage regulator to make suitable 6 volts.
    • Front suspension is wider by 5 mm. (80 mm front and rear now)
    • New main-board including NRF24L01 with L1117 3.3V regulator, Arduino Pro Micro 5V, TB6612FNG, big 1000uF capacitor for voltage spikes, buzzer for signalization low voltage or debug, 10k/4k7 voltage regulator was the same as before.
    • burned finfer by soldering iron :/, it survived (weird smell of human meat)
  • What I will make or add later
    • FPV camera on Yaw or Pitch servo
    • Spoiler on servo. Rly? Useless…. Maybe.
    • Better controller! with display or buzzer to know battery voltage of the car or the controller itselft.
  • Any ideas? craft@kovac.top / IG: kovacdottop

Freecading servo RDS3115

As I wanna build quadruped of servos I need to visualize all the parts in the computer. For 3D modeling I use FreeCad. It is simple and fast. Here is the model of servo I’ve done:

RDS3115

I’ve found out that the servo isn’t symetric. The side with bigger mount is 1 mm shifted to the left, so I have to be careful when modeling another parts where I will attach these servo mounts.

You can grab the FreeCad file here.