infrared remote controlled car

hi.iam doing a project in remote controlled car using t.v. remote control(sony) .
iam using a TSOP receiver to receive the signal.but, i need to decode only volume up/down,program up/down to control forward/backward,left/right movement and i want to accomplish this using 8051 microcontroller.help me in doing this task.

I used a Microchip PIC24FJ256GB110 for a similar project as it has built in IrDA controller (and free software from Microchip web site).
it would be worth you looking for an 8051 with similar functionality as it would probably simpilify the project.

Hi,

First copy IR burst patterns that emits by TV-remote (use IR sensor and copy received bit pattern to ROM of your 8051). Later you can use it to compare and with incoming signal. In this way you may use any TV remote regardless of their protocol.

First copy IR burst patterns that emits by TV-remote (use IR sensor and copy received bit pattern to ROM of your 8051). Later you can use it to compare and with incoming signal. In this way you may use any TV remote regardless of their protocol.

Click to expand...

Can you please explain in detail how to copy the burst to ROM.
Thanx in advance

Hi,

IR communication uses 38KHz modulation for most TV remotes . (SB-Projects: IR remote control / PIC Tutorial* Five - Infrared Communication) That means at every 26.3us input status can be changed (high or low)

So you connect IR-receiver to an input pin of uC. Then sample the state at every 26.3us.
You count how long each and every bit state exists.

Say you detected "High" state of IR-input, sample period is 26.3us; you counted 25000 samples and then IR-input state changes to "Low". Now you know that High state existed for 26.3 X 25000 us= 657.5 ms. You can store that 25000 on memory as time-period for that "High" state. Since your uC is 8bit, use 2-bytes to store such time periods. so you can count up to time period of (26.3us X 65535 =) 1.7 s

So each bit state you need 2-bytes. If your IR burst has 50 state changes, you need total of (2 X 50 =)100 bytes to store a single burst. Then you can store this on ROM.

Later when your remote controlled car receives a IR signal, you capture the burst same way in above, then compare it with stored-pattern in ROM, if found similar (you must implement some tolerance level) do the action you desire.

Hope this helps you and if need further explanation please ask.

s.k. sundar said:

hi.iam doing a project in remote controlled car using t.v. remote control(sony) .
iam using a TSOP receiver to receive the signal.but, i need to decode only volume up/down,program up/down to control forward/backward,left/right movement and i want to accomplish this using 8051 microcontroller.help me in doing this task.

Click to expand...

Practically looking in to the project, the car will only run when ir receives the IR signal from the handset. But once the car is turned away, how will the RX get the signals from the TX?