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Hack a Toy Car to Make a Cheap Wireless Robot

Hack a toy car to make a cheap wireless robot? Yes, cheap toy remote cars form china can be scavenged to get their remotes to work with our robots. All of us have seen and played with toy cars some time in the past. Some -like me- might have bought them to get the magnets inside those DC motors. I don’t know why those C shaped magnets caught my attention more than the car.

I have to admit even after growing older, I could not resist the urge to open a brand new toy remote car that my little brother had just broken (he broke the axle connecting the rear wheel and it was beyond repair). It was one of those cheap china products so no big deal. What I was interested in was the remote control. Here is an image of the remote and its receiver board which apparently was the H-bridge too!

DSC09479

Even the cheapest RF ASK modules cost around $7 and this entire car was price at around $10. Let’s say we just want the remote. Even then we can never make such a good looking enclosure for the transmitter in case of the RF module. This is the receiver cum motor driver circuit. I had seen all the wires and where they went so I didn’t have any trouble identifying them. But you could see the silkscreen and identify the wires.

remote receiver front

The next thing I did was to desolder those wires and add some custom wiring that could be plugged into my development board without looking messy. I soldered a 2 wire RMC connector to the power connectors so that I won’t mix up the positive and negative leads. Then I added a bus wire to take out the motor terminals and connected a female berg strip to its other end.

remote receiver back

The RMC connector that I had soldered on the power terminals was actually a bad idea. My development board did not have a suitable connector to receive the connector. I could have desoldered it and attached a berg jumper, but my iron takes its own sweet time to heat up. Besides I needed those connectors when I moved the board into the robot where it is going to stay for sometime before I get tired of it. So this was the most optimal solution that I could think of, the white casing around the RMC connector had to go, good old tricks sometimes saves a lot of trouble.

RMC connector

The idea is that, the four pins that came out of the board was to serve as inputs for the Microcontroller or directly be given to a motor driver IC like L293 or L298 depending on the size of the the motor your robot has.

For doing either of the above, we need to have a table of how the board would behave for various types of input. To figure this out I had to connect LEDs to the output of the receiver. My PIC development board, conveniently had 4 LEDs with a 4 pin male berg strip (trust me its pure coincidence :-)) all I had to do was to plug it in to see the output. You can also see the power cables connected to the power terminals of the board.

Connection

The next part was really simple, just send some signal form the remote to note down the LED patterns. When the LED turns on the corresponding bit has a logic HIGH. As soon as I was the first pattern the remaining were quiet obvious.  Here is what I observed.

Front 0001
Back 0010
Left 0100
Right 1000

I wanted to implement this setup in balckboy. All I had to do was remove some module (line sensors and comparators where not needed) form the robot and add this receiver and connect the inputs to PORT B.

wireless robot

Since the Blackboy already has a motor driver and a PIC microcontroller in it, I had to write a small program to get these values as inputs and move the robot accordingly instead of the much simpler alternative.

Thats all folks! Here is a video to demonstrate the output of the above procedure. Hope you like it 🙂

If you have any queries/suggestions leave a comment and I will try to answer then to the best of my abilities.  Subscribe to our blog to receive our latest posts and updates and newsletter in your inbox.

About Siddharth

Siddharth is a Firmware Engineer, techie, and a movie-buff. His interests include, Programming, Embedded Systems, Linux, Robotics, CV, Carpentry and a lot more. At times, you could see some of his sunday projects converge on release quality. You get to know him on the following social channels.

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  • Saraswathy Ramakrishnan

    Siddharth, I am really thrilled to see how creative you are.You are sure to develop into a good electronic inventor and I wish you all the best. God bless you
    Saraswathy

    • Thanks ma’am, your comment makes my day 🙂 I wish to do more with your blessings and motivation.

  • viki

    Doing a great job siddarth. Really I’m jealous of you. Do a spell check before posting . A lot of spelling mistake are there.

    • Thanks Viki.. 🙂 I usually do a spell check but this post seems to have slipped me. I will try not forgetting it here after, thanks again for the tip.

  • nitish

    hi dude super work 🙂 actually i need some help making a wireless module for my war robot please give some pointers and i have the same remote as the above video but i need more than 4 controls in it how do i do it?

    • Thanks Nithish, The transmitter (remote) in the above post is capable of transferring only 4 types of signals. I think it should be possible to some how tweak the remote to send more data but is a laborious task and the process may differ form one model remote to another. If your application demands more than 4 control signals then you should use the RF transceiver modules. Read this post for more information.

  • anand4

    can imake it from scratch (make homemade remote controller) if any send to my emai

  • Pingback: Make a Simple RC (Remote Controlled) Robot Car | Embed Journal()

  • Can you show me circuit diagram for your car

  • Hey that’s great! well done!
    a noob question! 😀
    you wrote some lines of code,where did u use them? i meant u wrote them for a chipset?
    and also whats that language? i think sth like C++

    • Silverman, Thanks. Those lines are embedded C code. It is written, compiled and burned into the microcontroller. This particular code reads data from the transmitter and then drives the motors accordingly.

  • sandeep kumar

    i am a student of class9 and i want a robot car based science project

    hurry up
    my science exhibition is in October 12
    please send in my e mail id how to make it

    it should be simple

    please send thankyou

    • Have you read this article? I think everything that has to be said is said in the article.

  • SRIDEV

    sir, please tell me hacking the old toy RC car for new wireless RC car

    • Hi sridev, I dont know you are trying to ask me. Did you read the post? what question are you having? Be more specific.

  • Hii Sid …u seem to be quite an interesting guy, can u tell me something to help me work with L293D motor

    • Read though my other post and you will get to know it.

  • pratik

    hey i want to make this but how to write the code in the circuit ?

    • You will have to read more of my posts to get an idea about embedded systems. Check out my PIC basic lessons.

  • veeru

    Sir how to get those board and small electronic things and from where

  • Sudeep Pittalwar

    hai sid i am using an atmega 16 board for controlling the robot …i wrote the program but i am not getting any output from if… can u please mail me the code in c for avr
    my id saisudeep333@gmail.com

  • Biswajit Naskar

    Dear Friend,

    I have like same RC car, but i don’t have remote.
    How i will make the remote?
    Can you help me for making this remote.
    Do you have diagram for this remote and details?

    Find The attached file.

    Thanks
    Biswajit

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