TV Remote Control

fathom

New Member
On a rummage around a skip I found a 26" LCD TV. It was an unknown make (Technosonic) and it didn't work. I found that one half of the on/off switch had failed so I bridged it and hey presto a working TV. The only bugbear was I couldn't find the remote control and I bought a universal remote and I couldn't get it to work.

On to the PICAXE project the only controls I really use on the TV are the volume controls and it would be nice to switch it off remotely. I had played with the INFRAIN command before but couldn't get it to work as trying to get the Sony compatible remote control was proving to be a bit of a pain.

I have found one remote that does generate the right Sony codes and you probably have one in your house. It is the humble SKY remote!! Set the code for the remote to 0000 and away you go.

I utilised the existing IR receiver mounted on a small PCB in the front of TV which also has a LED on it to show the status of the TV. I wanted to test it to make sure that it actually worked so I used the circuit below.



When the button on the remote is pressed the LED flickers which proves that it is working.

I decided to use the 08 chip as it had the right number of outputs I wanted and it seemed a better idea that waste an 18x. The program is fairly simple it waits for the correct key presses and then for the volume controls it just pulses the outputs which will close a relay contact which will be placed in parallel over the volume push button switch. The power output latches the relay and switches the power to the TV on, there is a 5 second delay to prevent accidentally turning off the TV if the power button is pressed too long or to counter switch bounce. Also when any of the commands are sent it flashes an extra LED to prove that signals are actually being received.

;Simple picaxe program to control my salvaged television using the sky remote
;control

;program to control tv using sky remote with PICAXE 08M
;pinout IRIN = pin 4
;Volume Up = pin 7
;Volume Down = pin 6
;Power on/off = pin 5
;IR signal received = pin 3

main: ;main program

infrain2

if infra = 18 then goto volumeup ;wait for signal from volume up key
if infra = 19 then goto volumedown ;wait for signal from volume down key
if infra = 21 then goto power ;wait for signal from power key

goto main ;loop back to main

volumeup: ;volume up subroutine
high 0,4 ;vol up key pressed? then make 0&4
high
pause 200 ;wait for a bit
low 0,4 ;switch 0&4 off again
goto main ;back to main

volumedown: ;volume down subroutine
high 1,4 ;vol down key pressed? then make 1&4 high
pause 200 ;wait for a bit
low 1,4 ;switch 1&4 off again
goto main ;back to main

power: ;standby subroutine
toggle 2 ;toggle 2
high 4 ;flash 4 high
pause 100 ;wait a bit
low 4 ;4 low again
pause 5000 ;wait 5 seconds to prevent accidental operation
goto main ;back to main
The circuit that will be used is as follows;



The relay that switches the mains voltage will be on a separate board along with a small power supply to step the voltage down from 240V to 5V to power the circuit. The TV would normal use the internal power supply to power the remote circuitry as when it is on standby its never actually off, but when this turns the power off it really will be off so it needs a separate power supply.

The hardware will be constructed when the bits I have ordered turn up from RS.
 
GOOD!

Hey mate as i am only young i wish to create some LED mods and sound mods for my xbox. i shall be using this to help me with my circuit where i will create a picaxe remote and reciever so i can press the button so it will change setting(flash or temp controll). Thanks again but do you knwo if there is a remote control that you can create for this circuit as i know they all have differant frequencies.
Trevor Boultwood
 

fathom

New Member
You can use a cheap universal remote.
On a rummage around a skip I found a 26" LCD TV. It was an unknown make (Technosonic) and it didn't work. I found that one half of the on/off switch had failed so I bridged it and hey presto a working TV. The only bugbear was I couldn't find the remote control and I bought a universal remote and I couldn't get it to work.
Read the post properly....
 

nick12ab

Senior Member
Try a different one then! Also, cheap ones do have a feature where you press the power button repeatedly until the TV turns off. Besides, it was for trevorboultwood
 
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