Troubleshoot with RF 315mhz M4 receiver and transmitter.
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Troubleshoot with RF 315mhz M4 receiver and transmitter.

by Denik_den1993 on Mon Feb 04, 2013 5:00 am

Hi guys, i am new here but i know some stuff about electronics. So a week ago I got my M4 receiver and transmitter Keyfob. I connected everything how it should be connected and how it says it should work is if i press button a the corresponding pin will go high in till i will release it. Well its not working like that when i press one of the buttons the corresponding pin blinks/flashes if i am like 1ft away it doesnt flash. So i tried different power supply but nope doesn't work. If some one could help me out it would be great. i hope i didn't spent my money useless.Thanks guys.
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Re: Troubleshoot with RF 315mhz M4 receiver and transmitter.

by Zener on Tue Feb 05, 2013 2:47 pm

Weak battery in the fob?
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Re: Troubleshoot with RF 315mhz M4 receiver and transmitter.

by adafruit_support_bill on Tue Feb 05, 2013 3:55 pm

Yes. I would try fresh batteries in the transmitter to see if that helps.
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Re: Troubleshoot with RF 315mhz M4 receiver and transmitter.

by EasternStarGeek on Sun Feb 10, 2013 7:50 pm

Funny, I just got one as well, and was puzzled by exactly the same thing. In my case, I also have the momentary receiver, and when I tapped the key (most of the time) I got a momentary pulse on the output, although it was sometimes a little jittery.

Whenever I hold the button down, however, I get the same pulses at the receiver that the OP observed. To my eyes, it looks almost as if the keyfob has an auto-repeat function. The pulse rate is approximately 2Hz. I suppose I should check the battery, but my unit was ordered only last week.

AFI- does this unit, in fact, auto-repeat?

I will let you know how I make out.
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Re: Troubleshoot with RF 315mhz M4 receiver and transmitter.

by adafruit_support_bill on Mon Feb 11, 2013 7:18 am

Thanks ESG. Let us know the results of your test. I'll try to confirm from this end.
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Re: Troubleshoot with RF 315mhz M4 receiver and transmitter.

by adafruit on Mon Feb 11, 2013 12:08 pm

can you help us by typing out the part number on the receiver? does it end with M4?
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Re: Troubleshoot with RF 315mhz M4 receiver and transmitter.

by Zener on Mon Feb 11, 2013 1:57 pm

I think fobs of this general type generally do auto repeat. But, how that would be interpreted at the receiver I don't know. I will leave that to you all to nail down. It's not in the documentation of the product?
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Re: Troubleshoot with RF 315mhz M4 receiver and transmitter.

by adafruit on Mon Feb 11, 2013 4:18 pm

These are not really meant to be sold for DIY use - they're used for like, garage door openers, so the only documentation we have is the chip datasheets!
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Re: Troubleshoot with RF 315mhz M4 receiver and transmitter.

by Zener on Mon Feb 11, 2013 5:26 pm

The Mfg has a greatly improved datasheet on their web site:

http://www.princeton.com.tw/Portals/0/P ... 2262_5.pdf

The answer appears to be on page 9:

"CODE FRAME
A Code Frame consists of four (4) continuous Code Words. When PT2262 detects “0” on the /TE (meaning, the /TE is
active “low”), it outputs a Code Frame at DOUT. If /TE is still active at the time the Code Frame transmission ends, T2262
outputs another Code Frame."
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Re: Troubleshoot with RF 315mhz M4 receiver and transmitter.

by Denik_den1993 on Tue Feb 26, 2013 1:29 am

Thanks guys for replies, yeah I thought about idea of weak batter I am going to try that. I hope thats the case, cuz my application requires momentary function. Thank you again!!! I will keep you updated!
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Re: Troubleshoot with RF 315mhz M4 receiver and transmitter.

by Denik_den1993 on Tue Feb 26, 2013 1:40 am

Hi Zener. sorry I didn't really understand why it does this kind of thing. the thing is when the transmitter is about 1-4 feet from receiver it works perfectly, but not further. I have tested out the range even with blinking, and I get about 60m. If you explain me the meaning of that part I will appreciate it! thanks
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Re: Troubleshoot with RF 315mhz M4 receiver and transmitter.

by adafruit_support_bill on Tue Feb 26, 2013 7:40 am

What zener is saying is that the transmitter is not putting out a continuous signal, but a series of 'code frames'. That explains the blinking. But it does not explain why the distance matters.

When you do these tests, have you fully extended the antenna wire on the receiver?
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Re: Troubleshoot with RF 315mhz M4 receiver and transmitter.

by b_r_jones on Mon Mar 11, 2013 11:46 pm

Hi, I'm having the exact same problem with a couple of key fobs... Do we know if this problem was corrected and what corrected it?

Thanks!!!

Brian
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Re: Troubleshoot with RF 315mhz M4 receiver and transmitter.

by Zener on Tue Mar 12, 2013 12:27 am

Here is the data sheet for the decoder end:

http://www.princeton.com.tw/Portals/0/P ... PT2272.pdf

On page 13 is the decoder algorythm/flow chart.

It says there that the momentary type resets the output after two address receives that do not match the decoders address.

So to me that suggests that the S/N ratio is going bad and so it is losing good transmissions. Different things could cause that, like the antenna, receiver or transmitter circuitry. That's just a guess of course.

What is the range supposed to be?
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Re: Troubleshoot with RF 315mhz M4 receiver and transmitter.

by adafruit_support_bill on Tue Mar 12, 2013 6:45 am

The range is going to vary quite a bit depending on conditions. This is particularly true of indoor operation.

Have you uncoiled the antenna? You should straighten it out for best reception range.
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