[mythtv-users] IR Tranmitter
Colin McGregor
colin.mc151 at gmail.com
Sun Sep 27 11:29:52 UTC 2009
On 9/27/09, Bert Van Kets <mythtv-users at vankets.com> 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.
If you are after a high power transmitter you might want to have a look at:
http://iguanaworks.net/product2.psp
Schematics and PCB layout are available on the website. My problem has
been to find a local source for the 0.33 F capacitor (yes, 1/3 of one
farad...).
> 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.
As a rule if you have two identical devices with identical remotes you
will need two independent transmitters. There are a SMALL number of
exceptions out there. I have a JVC VHS VCR that is one of the few
exceptions. The JVC was designed so that you could set-up the VCR / IR
remote so you could have two of that model VCR in the same room
controlled independently. That VCR is very much the exception to the
rule.
Sounds like you may want to go with one of the short range
transmitters and then tape the IR transmit LED right over the device
sensor.
> Thanks
>
> Bert
Colin McGregor
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