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i am looking to build a simple transmitter that will transmit on 433mhz automatically every 20ms or less. would this even be possible to make?

the transmitter only needs to be simple and set off a very short range buzzer attached to a simple receiver. the device will have to use 433mhz and run from battery power.

Dave Tweed
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Mick
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    I don't see any reason it wouldn't be possible. – Hearth Oct 12 '18 at 22:17
  • what components would you recommend? – Mick Oct 12 '18 at 22:37
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    I dunno. What do you need to transmit? What's your budget? You need a lot more details before we'll be able to help. – Hearth Oct 12 '18 at 22:41
  • sorry im not the most technically minded. but ive updated the question – Mick Oct 12 '18 at 23:01
  • Ain't that what basically the garage door keys do - bursting a byte of info? – sx107 Oct 12 '18 at 23:20
  • There may be some FCC or equivalent regulations covering the automated continuous use of the free bands. The rationale is that the bands should be able to support as many users as are in radio range. This means limited power and limited on time. No clear recollection for your case but continuous carrier is specifically not allowed. What would happen if you wanted 5000 of your gadgets in one shopping mall. – KalleMP Oct 14 '18 at 19:18

1 Answers1

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No, you can't. Besides, why do you need to update the status of a buzzer every 20 ms1 anyway?

The FCC puts strict limits on the duty cycle of "automatic transmissions", including the fact that the period cannot be less than 10 seconds under any conditions.

There's a good summary of the rules in this TI application note: ISM-Band and Short Range Device Regulatory Compliance Overview

1 Hmm. If you're trying to transmit something like Morse Code, I'm afraid you'll have to find a more efficient encoding scheme.

Dave Tweed
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