How to convert a wired toy car into a wireless robot car?
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Being a beginner into aeromodelling, it would be better off to start with a wired robo using a very simple chassis (a body on which you can mount wheels, motors, etc.), 4 DC motors preferable 300 RPM, a pair of two-way switches, each pair controlling the left side motors (2 motors are on the left and 2 on the right) and another controlling the right side motors.
Anyways coming to increasing your level in robotics, you can go for wireless, making your wired robot wireless requires some circuitry and a mobile power source onboard. I will give you the easiest option and it is to hack the wireless parts of your remote controlled cars but remember making it yourself would be the most satisfying thing in the world. Here is the link to my first hub on How to make a Remote Controlled Robot Car?
The most difficult bit is getting a controller connected and programing it, using a DC motor will not be easy for beginners and I would recommend servos for that.
So ideally your first step is to get: 1. Microcontroller. 2. Development board. 3. The connecting stuff. 4. Servos.
And try to program or get a downloaded PWM code working, depending on button or sensor.
Another question here arises is that is the microcontroller programming possible in C? My suggestions are that if you have succeeded to make a wired robot, to make it wireless you can do following.
1. If you are not familiar with microcontrollers , better to start now. Use PIC microcontrollers (start with 16F628) with "PIC BASIC" or if you don't have access to PICs in your areas, try 89c2051 with "BASCOM", as both BASCOM and PIC BASIC are basic compilers and it will be very easy to start the programming.
2. For batteries, do not use NICD or nickel cadmium batteries, but use NiMH batteries.
3. Also, you can get the old laptop batteries from electronics scrap. Open the laptop battery and check the internal bank of batteries for working ones. As these are Li-ion or Lithium ion batteries, they have very good capacity. Be aware while charging these batteries, you will need to make a proper charger; otherwise, these will burst, as I have experienced it.