The document describes a robot car that is controlled using the keys on a mobile phone. The car uses an Atmega16 microcontroller and MT8870 DTMF decoder chip to interpret tones from the phone's keys and send commands to motors via an L293D motor driver. Pushing different phone keys (2, 8, 5, 4, 6) causes the car to go forward, backward, stop, left or right. The mobile phone eliminates limitations of range and obstructions compared to RF or IR remote controls. Schematics, code and instructions are provided to build the phone-controlled robot car.

1. Developed a robot car and manoeuvered it using Mobile Phone.
We all have witnessed Interactive Voice Response (IVRS) system where we key in different numbers to navigate through options.
Can we do something interesting with keys? Yes, we can.
I found this interesting project in EFY magazine. So, I decided to make a Toy Car that can be controlled with a mobile phone. The
Advantage of using the mobile phone as controller is that it eliminates the limitations of range and obstructions as in case of RF or IR
signals.
Watch the video and you will find the car being guided through the cellphone keys.
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2. IC's
1. Atmega16 AVR
2. MT8870 DTMF Decoder
3. L293D Motor Driver
4. 74LS04 NOT Gate
Crystals
1. 3.57Mhz Crystal
2. 12MHz Crystal
Resistors
1. 100K x2
2. 10K x5
3. 330K x1
Capacitors
1. 22pf x4
2. 0.47uf x1
3. 0.1uf x1
Misc
1. IN4007 Diode
2. Push To ON switch
3. 6v, 50 RPM motors x2
4. Mobile Phone
5. Earphones x1
6. 6v, 4.5Ah Battery (I used 3.7v Li-ion batteries)
The schematic is self explanatory.
Use any PCB designing tool to create the PCB Layout (I used ExpressPCB). You can use the datasheets of the used IC's in order to
identify the exact location of pins of used components.
You Can Also use a general Purpose PCB and Solder the components according to your design.
Mount the Motors On the Edges of PCB board and connect to the motor driver IC.
use any Stick or a pencil to mount the front tyres.
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3. I have Compiled Code using AVR Studio. The HEX file is uploaded and you can use any programmer to burn the code in your Atmega
Controller(I used ISP Programmer available on www.Robokits.co.in).
1. Cut the earphone wires about a distance of 10 cm from the 3.5mm jack.
2. Strip the wires and identify the TIP and RING using Connectivity mode in multimeter.
3. Solder the TIP and RING wires on the PCB board.
4. Connect a mobile phone using the audio jack on the soldered earphone wire.
5. Place the phone on the car and make a call using your cell phone.
6. Different Key press on the phone sends different DTMF (Dual Tone Multi-Frequency) tones to the car.
7. Our Microcontroller is coded to make decisions on some of the key presses,
key 2- FORWARD
Key 8- BACKWARD
Key 5- STOP
Key 4- LEFT
Key 6- RIGHT
Design The Car according to your creativity and needs.
All The Best.
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Download GSM Controlled Car - All as pdf http://instructables-pdf.abuouday.com/download.php
3 of 3 10.11.2015 22:39