[mythtv-users] IR Tranmitter

[Bert Van Kets]

William wrote:
> Bert Van Kets wrote:
>> William wrote:
>>  
>>> Bert Van Kets wrote:
>>>    
>>>> I need to build an IR transmitter to set the channels on my cable box
>>>> (Belgian Telenet Digibox). Anybody try the three component circuit on
>>>> http://www.lirc.org/transmitters.html or is it necessary to use the
>>>> higher power one further down the page.
>>>>
>>>> How can I find out what frequency I need to transmit? How do I set it?
>>>>
>>>>         
>>> The cheap one will usually work ok for one device. The output is
>>> pretty weak so you need to tape it right over the sensor. The high
>>> power one will allow you to control several devices from one emitter.
>>>
>>> To find the frequency. Find a lirc configuration for your device and
>>> look at the top of the file. The frequency is shown in the info there.
>>> But in actuality, it does not matter as long as you install the
>>> correct conf files for your device. The config tells lirc what freq to
>>> use.
>>>
>>> William
>>>     
>>
>> Thanks William.
>> I will need to control at least two devices, so I'll have to go with the
>> transistor amplified one. It struck me that the NPN transistor is not
>> specified. Anybody got any suggestions? I can convert a circuit to a PCB
>> and build it, but designing a circuit is beyond my skills.
>>   
>
> The circuit will work find with any generic small signal npn
> transistor such as the venerable 2n2222. Just make sure its rated for
> at least 100ma collector current and you will be fine. You are just
> using it as a current amplifier which is also known as an
> emitter-follower circuit.
>> If I have two identical devices with identical remotes, won't I need to
>> hook up two transmitters? How else will the computer be able to set the
>> channels in the devices independently.
>>   
> Some devices such as the dishnetwork receivers allow you to setup
> multiple codes others you are stuck with a single code. In the single
> code scenario  you will need to make 2 transmitters (perfect used for
> the low powered model) and run two instances of lirc. Of course this
> will require 2 serial ports. From what I understand, you cannot use a
> USB-Serial converter. The control of individual pins is not possible
> with those.
>
> William

Thanks a lot all. With a little hrlp of the lirc site I should get
everything running. Now where did I leave that box with spare time????

Bert