# Controlling speed of motors

Discussion in 'The Projects Forum' started by André Ferrato, Apr 5, 2015.

1. ### André Ferrato Thread Starter Member

Apr 5, 2015
206
1
First, don't read this introduction if you're just interested in the content of the thread.

Hi, it has been a long time since i last used my english, so i'll start by apologizing for any mistake i make. I'm new to eletronics and i'm trying to build a simple RC car. I usually learn things by practicing and making mistakes, and that is no different with eletronics, so i found a simple rc car on the web and i'm trying to learn things by using it as a base. The tutorial is this one:http://embedjournal.com/make-a-rc-robot-car/ , as you experts may see it's a very simple car, that uses 4 switches, encoders and decoders. I googled and learnt a lot about everything and i'm starting to understand a bit of it.

Ok, the circuits on the web are:

TRANSMITTER

Diagram

http://i.imgur.com/LKB4EKH.png

PCB
http://i.imgur.com/xnfrLBx.png

Diagram

http://i.imgur.com/XjgZfBw.png

PCB
http://i.imgur.com/piD4s32.png

As you may see, it uses four switches, and if i'm not wrong, it has no speed control. So i would ask someone to help me transform this on to 2 switches, with potentiometers, these are the things that control speed, through pwm, i'm a right ? Remembering, i'm completely new to this.

Jul 18, 2013
10,860
2,525
The way I see it, what you have is essentially a simple digital Tx/Rx control system and want to include a variable signal using an analogue signal to control a PWM drive on the Rx end?
This is similar to the way it is done in hobby RC controllers, for which you would have to simulate.
I don't really see a way to do it with the current components used.
Max.

3. ### Dodgydave AAC Fanatic!

Jun 22, 2012
5,159
772
the HT12 chips, transmitt high or low on four data lines, they can use multiple receivers on one transmitter using different addressed pins, they dont do analogue outputs.

4. ### André Ferrato Thread Starter Member

Apr 5, 2015
206
1
Understood, i am really new at this. So what components should i use instead ? Or better, what would you change ?

Jul 18, 2013
10,860
2,525
Unless you are seeking the academic experience of building it yourself, it hardly seems worth it when you can buy a fairly sophisticated TX/RX for <\$25.00 from Hobby king et-al.
Max.

6. ### André Ferrato Thread Starter Member

Apr 5, 2015
206
1
Yes i am seeking the academic experience of building it all by myself, so i sought the help of experienced guys like you. I wanted to change the circuit so i could control the speed of motors and not need four switches to manage it. I may be speaking or asking things that are maybe obvious to you, but i insist that if i am please tell me. So the hobby rc cars, normally have two switches and the longer you push the button the fast the car would go, basically that's all i want to do, but i dont know if it is possible to do in this one, or if it is possible, is it hard ? What needed to be changed?