Mobile controlled Robot

We are using mobile phones to do a lot thing like calling, chatting etc. But have u wondered controlling ur bot from ur mobile phone. In this post i will tell u how to build ur own mobile controlled bot.

DTMF tones

The heart of this bot is the DTMF decoder IC. First u must understand what r DTMF tones?.DTMF is Dual Tone Multi-Frequency signalling which is used in telephones. Whenever we press a key in the keypad we will hear a tone. This tone is distinct for each key. These tones are called DTMF tones. Each tone is a combination of two frequencies. The table below gives the frequencies and the corresponding keys.

DTMF decoder

IC8870 is a DTMF decoder. It will decode the DTMF tones and tell us what key is pressed. The output of the ic will reflect the key pressed. For example if you press 2 the output will be “0010”. The circuit diagram for the DTMF decoder circuit is below.

Building the bot

You can use the simple bot as the skeleton. Then program the microcontroller in such a way that if you press 2 the bot should move forward, 8 means reverse, 4 means left and 6 means right. The important thing to note is that you need two mobile phones for this to work. One mobile phone must be attached to the bot via a 3.5mm jack. The other is used as remote. After assembling everything make a call to the mobile attached to the bot. Press the answer button and from the dialed mobile you can control the bot. 

Mobile controlled bot

Here is the video of my bot