IR Receiver/Demodulator [Design]

Prev: Microeconomics 5e Jeffrey M. Perloff test bank and solution manual is available for purchase at affordable prices. Contact me at alltestbanks11[at]gmail.com to buy it today.
Next: Essentials of the Legal Environment 2nd Edition 2008 Roger LeRoy Miller Test bank is available for purchase at affordable prices. Contact me at alltestbanks11[at]gmail.com to buy it today.

From: Phil Hobbs on 18 Mar 2010 17:31

On 3/18/2010 5:18 PM, Martin Brown wrote:
> Jan Panteltje wrote:
>> On a sunny day (Thu, 18 Mar 2010 12:11:21 -0500) it happened "eeboy"
>> <jason(a)n_o_s_p_a_m.n_o_s_p_a_m.jasonorsborn.com> wrote in
>> <woydnU4jer8kwz_WnZ2dnUVZ_oadnZ2d(a)giganews.com>:
>>
>>> Spent a day playing around with the optics which yielded no major
>>> improvements.
>>
>> I wanted to say this before, it is a weird thread, but at that
>> distance use a 430 MHz transmitter receiver module.
>
> I agree. That or one of the generic cheap model car control modules
> which claim ranges roughly in the right ball park. Without error
> correction on the data sent this thing is headed for a fairly major
> train wreck.
>
> Meade stock was once pumped up in the .com (con) boom on the basis of
> high bandwidth building to building coms using 8" SCTs as the optics.
>
> http://www.space.com/businesstechnology/business/meade-telescope_000317.html
>
>
> Regards,
> Martin Brown

Terabeam, RIP. I recently bought 75 of their beautiful 1.3 um APD/TIA
modules for about 75 cents apiece--probably half a cent on the dollar.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net

From: Hammy on 18 Mar 2010 17:59

On Thu, 18 Mar 2010 20:53:49 -0000, "markp" <map.nospam(a)f2s.com>
wrote:

>
>"Hammy" <spam(a)spam.com> wrote in message
>news:j315q5t6flb0o0nemdrv2ngh5ig9jjesc8(a)4ax.com...
>> On Thu, 18 Mar 2010 19:29:49 GMT, Jan Panteltje
>> <pNaonStpealmtje(a)yahoo.com> wrote:
>>
>>>On a sunny day (Thu, 18 Mar 2010 12:11:21 -0500) it happened "eeboy"
>>><jason(a)n_o_s_p_a_m.n_o_s_p_a_m.jasonorsborn.com> wrote in
>>><woydnU4jer8kwz_WnZ2dnUVZ_oadnZ2d(a)giganews.com>:
>>>
>>>>
>>>>Spent a day playing around with the optics which yielded no major
>>>>improvements.
>>>
>>>I wanted to say this before, it is a weird thread, but at that distance
>>>use a 430 MHz transmitter receiver module.
>>
>> http://canada.newark.com/microchip/mrf49xa-i-st/rf-transceiver-ic/dp/08R1857?Ntt=MRF49XA-I/ST
>
>Or if you wanted to avoid the impedance matching stuff and layout issues use
>the RFM12B module. Similar price, good performance. That module is available
>in 868 and 915MHz variants as well with a minor firmware change. Actually
>this Microchip part seems identical to the Si4421 chip used on the RFM12B
>with just some signal name changes!
>
>Mark.
>
The data sheet comes with a layout and BOM.

But frankly I don't understand why he's only getting 8 ft range. I've
never tested mine in direct sunlight but I know at dawn/ dusk I get a
helluva lot further then that.

Even if you Google IRDA ,IR BEAM etc. you'll find all sorts of
examples of people getting hundreds of feet transmission distance with
no special optics. A fresnel lens diffuses so I don't think that's
helping for one.

As for an IR lens that filters out sunlight and other wavelengths just
rip one out of an old TV,STEREO whatever. All IR remote devices in my
house have a filter lens in front of the detector. I'm sure you could
find a scrap TV or something to scavenge one off for testing.

I recall finding sources for the lens you can get it in strip form. I
cant find the site anymore but its inexpensive.

From: Phil Hobbs on 18 Mar 2010 18:22

On 3/18/2010 5:59 PM, Hammy wrote:
> On Thu, 18 Mar 2010 20:53:49 -0000, "markp"<map.nospam(a)f2s.com>
> wrote:
>
>>
>> "Hammy"<spam(a)spam.com> wrote in message
>> news:j315q5t6flb0o0nemdrv2ngh5ig9jjesc8(a)4ax.com...
>>> On Thu, 18 Mar 2010 19:29:49 GMT, Jan Panteltje
>>> <pNaonStpealmtje(a)yahoo.com> wrote:
>>>
>>>> On a sunny day (Thu, 18 Mar 2010 12:11:21 -0500) it happened "eeboy"
>>>> <jason(a)n_o_s_p_a_m.n_o_s_p_a_m.jasonorsborn.com> wrote in
>>>> <woydnU4jer8kwz_WnZ2dnUVZ_oadnZ2d(a)giganews.com>:
>>>>
>>>>>
>>>>> Spent a day playing around with the optics which yielded no major
>>>>> improvements.
>>>>
>>>> I wanted to say this before, it is a weird thread, but at that distance
>>>> use a 430 MHz transmitter receiver module.
>>>
>>> http://canada.newark.com/microchip/mrf49xa-i-st/rf-transceiver-ic/dp/08R1857?Ntt=MRF49XA-I/ST
>>
>> Or if you wanted to avoid the impedance matching stuff and layout issues use
>> the RFM12B module. Similar price, good performance. That module is available
>> in 868 and 915MHz variants as well with a minor firmware change. Actually
>> this Microchip part seems identical to the Si4421 chip used on the RFM12B
>> with just some signal name changes!
>>
>> Mark.
>>
> The data sheet comes with a layout and BOM.
>
> But frankly I don't understand why he's only getting 8 ft range. I've
> never tested mine in direct sunlight but I know at dawn/ dusk I get a
> helluva lot further then that.
>
> Even if you Google IRDA ,IR BEAM etc. you'll find all sorts of
> examples of people getting hundreds of feet transmission distance with
> no special optics. A fresnel lens diffuses so I don't think that's
> helping for one.
>
> As for an IR lens that filters out sunlight and other wavelengths just
> rip one out of an old TV,STEREO whatever. All IR remote devices in my
> house have a filter lens in front of the detector. I'm sure you could
> find a scrap TV or something to scavenge one off for testing.
>
> I recall finding sources for the lens you can get it in strip form. I
> cant find the site anymore but its inexpensive.

You can go for miles and miles in the dark, if your aiming is good
enough. During the day, even if you get rid of the DC, you're still
buried by the shot noise of the sunlight. It's horrendous. Try
calculating your expected noise floor--it isn't hard, and it's very
instructive.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net

From: markp on 18 Mar 2010 18:30

"Hammy" <spam(a)spam.com> wrote in message
news:2p75q51q8ao2vt8o3vjmoal2c9gcuot9h1(a)4ax.com...
> On Thu, 18 Mar 2010 20:53:49 -0000, "markp" <map.nospam(a)f2s.com>
> wrote:
>
>>
>>"Hammy" <spam(a)spam.com> wrote in message
>>news:j315q5t6flb0o0nemdrv2ngh5ig9jjesc8(a)4ax.com...
>>> On Thu, 18 Mar 2010 19:29:49 GMT, Jan Panteltje
>>> <pNaonStpealmtje(a)yahoo.com> wrote:
>>>
>>>>On a sunny day (Thu, 18 Mar 2010 12:11:21 -0500) it happened "eeboy"
>>>><jason(a)n_o_s_p_a_m.n_o_s_p_a_m.jasonorsborn.com> wrote in
>>>><woydnU4jer8kwz_WnZ2dnUVZ_oadnZ2d(a)giganews.com>:
>>>>
>>>>>
>>>>>Spent a day playing around with the optics which yielded no major
>>>>>improvements.
>>>>
>>>>I wanted to say this before, it is a weird thread, but at that distance
>>>>use a 430 MHz transmitter receiver module.
>>>
>>> http://canada.newark.com/microchip/mrf49xa-i-st/rf-transceiver-ic/dp/08R1857?Ntt=MRF49XA-I/ST
>>
>>Or if you wanted to avoid the impedance matching stuff and layout issues
>>use
>>the RFM12B module. Similar price, good performance. That module is
>>available
>>in 868 and 915MHz variants as well with a minor firmware change. Actually
>>this Microchip part seems identical to the Si4421 chip used on the RFM12B
>>with just some signal name changes!
>>
>>Mark.
>>
> The data sheet comes with a layout and BOM.
>
<snip>

It does, but maybe you'd rather not do it. The RFM12B is available at about
$2.10 in 1000off and has already been compliance tested, it lowers risk that
the final product is compliant. You'd still need the BOM parts with the
MRF49X in addition to the chip and get them placed on the PCB. In larger
quantities the MRF49X solution might be more cost effective, but I don't
think there's much in it.

Mark.

From: Joerg on 18 Mar 2010 18:26

Phil Hobbs wrote:
> On 3/18/2010 5:18 PM, Martin Brown wrote:
>> Jan Panteltje wrote:
>>> On a sunny day (Thu, 18 Mar 2010 12:11:21 -0500) it happened "eeboy"
>>> <jason(a)n_o_s_p_a_m.n_o_s_p_a_m.jasonorsborn.com> wrote in
>>> <woydnU4jer8kwz_WnZ2dnUVZ_oadnZ2d(a)giganews.com>:
>>>
>>>> Spent a day playing around with the optics which yielded no major
>>>> improvements.
>>>
>>> I wanted to say this before, it is a weird thread, but at that
>>> distance use a 430 MHz transmitter receiver module.
>>
>> I agree. That or one of the generic cheap model car control modules
>> which claim ranges roughly in the right ball park. Without error
>> correction on the data sent this thing is headed for a fairly major
>> train wreck.
>>
>> Meade stock was once pumped up in the .com (con) boom on the basis of
>> high bandwidth building to building coms using 8" SCTs as the optics.
>>
>> http://www.space.com/businesstechnology/business/meade-telescope_000317.html
>>
>>
>>
>> Regards,
>> Martin Brown
>
> Terabeam, RIP. I recently bought 75 of their beautiful 1.3 um APD/TIA
> modules for about 75 cents apiece--probably half a cent on the dollar.
>

Sometimes this stuff seems to work though:

http://www.modulatedlight.org/Dollars_vesus_Decibels_colour.pdf

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.