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Pimpom
04-05-2010, 01:48 AM
Hi, I'm new here. Normally, I'd lurk for a while and become familiar with a forum before posting. But I need some information quickly and I hope some of you can help me.

I have some experience in designing and constructing electronics circuits, but I live in a remote area and often have difficulty sourcing components. Right now I badly need a few 56kHz IR receiver modules for a vital project. I'd prefer Vishay TSOP34156 but other types may also do.

Farnell have it but they require a sales tax registration number which I don't have. RS are really nice to deal with but they don't have it. Indigenous Indian shops and companies are difficult to deal with from a distance unless the amounts involved are large.

I have some people in New Delhi and Kolkata who can buy it and send it to me, but they don't know anything about electronics and I don't want to ask them to spend a lot of time searching for it. So I'll be grateful if anyone can tell me where I can get the part in Delhi or Kolkata, preferably Delhi.

akshay66
04-05-2010, 10:39 PM
Go to lajpat rai market.I'm not sure but there are a few shops you can try.

If you tell us more about your project maybe i think i could provide with you an alternative.

56Khz is rare whats the problem with 38Khz???

Pimpom
04-06-2010, 01:00 PM
Thanks for the reply. Of all the major Indian cities, I'm least familiar with Delhi. I've been there twice, but those were very brief visits and they were long ago. I've heard about Lajpat Rai Market. Is it something like Lamington Road in Mumbai, Chandni Chowk in Kolkata or Richie Street in Chennai?

Anyway, to answer your question: My project is not about robots. The 56kHz system is to be used along with a 38kHz system. I want to project two IR beams in parallel, about 18cm apart, and have the receivers about 8m away. It's to be a block/unblock presence detection system. No data to be sent. The two Tx-Rx pairs must work independently without interfering with each other. I've explored some possibilities in my mind:

1. Beaming the two systems with tubes and small apertures: Calculations indicate that this will require too much hassle in alignment precision, especially since the rays are invisible. Besides, this is not to be a fixed installation and has to be quickly set up and dismantled later.

2. Coding the IR pulses: 1) I have only a limited knowledge of microcontrollers and encoding/decoding technology. I could read up on those, but this is a time-bound project and I really don't have the time for now. 2) Standard codes as used in TV remote controls are too slow. I need reaction times of 1 millisecond or less. 3) Procuring the hardware will again be a hassle from where I live.

3. Pointing the beams in opposite directions: This should work except for reflections causing false triggering. I have not completely abandoned this option and may have to use it if I cannot find the 56kHz receivers.

So, using two IR beams of different frequencies seems to be the most straightforward solution. I can get 36kHz receiver modules, but this is still within the pass band of 38kHz modules. I've made the PCBs for the Tx, Rx and associated systems and are all ready to be put together.

On a side note: This is the newest thread in this section. Why is it buried near the bottom of the second page?

pkshima
04-06-2010, 06:48 PM
Thanks for the reply. Of all the major Indian cities, I'm least familiar with Delhi. I've been there twice, but those were very brief visits and they were long ago. I've heard about Lajpat Rai Market. Is it something like Lamington Road in Mumbai, Chandni Chowk in Kolkata or Richie Street in Chennai?

Yes.


On a side note: This is the newest thread in this section. Why is it buried near the bottom of the second page?

So that everything appears in chronological order. It shouldnt be a problem, because when you click on the topic, it automatically lands you to the first unread post.