RF remote control blocked by another transmitter  - Page 1
Forum section: electronics / beginners

author: Rigolon
author_rank: Regular Contributor
timestamp: August 14, 2019, 08:57:14 pm
content: Hey guys,I'm having a problem, that I don't know if it's possible to solve.I have a simple circuit to lock and unlock a door using a solenoid. It has an off the shelf RF module and the transmitter has rolling code and allows to register only 2 transmitter.I used my transmitter to unlock the door at the same time my wife turned on the car alarm, and the door didn't unlock. I noticed that whenever the alarm transmitter was being used, my system didn't recognize my own transmitter. I believe that both transmitter are in the same frequency range (433MHz).But is there a way to solve this problem without replacing my module for another frequency? And replacing for another frequency would solve this problem? (given that there are no other transmitter using that same frequency).

author: Audioguru again
author_rank: Regular Contributor
timestamp: August 15, 2019, 01:34:36 am
content: Your radio system is too simple and too old.My radio controlled model airplane "toys" operate at 2.4GHz and use automatic spread spectrum frequency hopping. At least 200 of them can be used at the same time with no interference.

author: Rigolon
author_rank: Regular Contributor
timestamp: August 15, 2019, 01:02:22 pm
content: Well...I guess the idea it is to be "too simple". About being too old I give you thatNot sure if the worry about being too simple is because I said that it's used to open a door. But if it's that it's only the dog kennel door.The 433MHz modules and transmitters are really cheap and has the rolling code to protect against copy, also I can find them anywhere. That's why I chose it. I didn't have much chance to look on the 2.4GHz yet, but will do it as soon as possible. If you could suggest some parts that would be appreciated.EDIT: Also, if anyone could suggest ideas or links on how I could build my own transmitter that would be a nice project so I can learn more.

author: Benta
author_rank: Super Contributor
timestamp: August 15, 2019, 04:12:35 pm
content: Since you mention 433 MHz, I assume you're in Europe. The 433 band is pretty smashed up from babyphones, remote controls etc. and is not well regulated.If you have the option. I'd recommend that you switch to 868 MHz instead. The rules on power levels, and duty cycle are much stricter there. Mind you, you may run into conflicts with car key fobs, but as they're only active for a second or so, it's usually not an issue.

author: Rigolon
author_rank: Regular Contributor
timestamp: August 15, 2019, 05:55:07 pm
content: Quote from: Benta on August 15, 2019, 04:12:35 pmBrazil actually, never really took the time to fix my profile.Quote from: Benta on August 15, 2019, 04:12:35 pmMy "problem" is that I'm running into conflicts with car key fobs, so not sure if I should just change to 868MHz.It's not really a problem since I could just press the button again after a few seconds to open the door. It's just out of curiosity and a means to learn something. I got really interested in the 2.4GHz, since it's commonly used. And as I'm hoping to one day work as a electronic designer, it should be really nice to know how to make something that is commercially used.