Credit Card Swipe Interference

This sort of protocol can be really difficult to solve. I'll say a few words about a project I was involved with years ago.

A "new node" didn't ping rather it listened - basically it picked-up on any nearby node that was already a member (it was listening for the node_members regular hub transmission). Doing it this way means the new_node didn't interfere with anything and, could silently choose the optimum "parent" i.e. the node_member with the most efficient transmission to the hub (master).

At regular intervals (obviously recognizable by the new_node), each node_member had a small timeslot to accept a "new node" request (should one come along). Basically this worked because there was always a "spare" receive time slot "offered" by only one node_member at a time that could be used for the new_node to make its presence known.

Once the parent (node_member) adopted the new_node, the whole network then had to accomodate space for the new guy to become a bona fide node_member and this does take some thinking about.

It's an interesting problem and probably best solved and developed by writing a PC program that simulates a variable system with random path losses and drop-outs. That's what we started to do but, the job fell-through for commercial reasons that I don't need to go into.

This is not a case of in-band interference, because 372 MHz is of course three orders of magnitude higher than 800 kHz (and there will be no significant harmonics that high, even on a digital signal). Therefore, I do not expect that putting more band filtering on the receiver will help all that much.

If you want to try anyway, the simplest thing in that area is to use a shortened antenna — one which contains, or is entirely, a coil. (This is a high Q antenna, one with a small relative bandwidth.) You'll need to make a friend who owns an antenna analyzer or dip-meter to get it tuned spot on, but given that it shouldn't be hard.

An alternative explanation is that the LED control signals are getting into the receiver circuit after the RF tuned part and upsetting it — either by radiation or through the power cable. Ideally, you'd quiet down the LEDs by shielding and ferrites on the data lines, but of course that would block the light from the LED strips since the data runs through them! (I'm assuming you're using the popular modern individually-addressable LED strips, since you mention things like adjusting the data rate.)

So, maybe try putting ferrites on the power cord to the opener, and foil tape on any cracks or non-metallic parts of the housing that aren't where the antenna is. Lots has been written on how to buy and use ferrite toroids, and I am not an expert in the area, so I can only say “read about it”.

A cheap (~\$20-\$40) investment in measurement tools you might be interested in is getting an RTL-SDR device. You can plug it into your laptop or phone, tune to 372 MHz, and watch what effect your LEDs have (or don't) on that part of the spectrum. (Make sure the AGC is turned off!) This will tell you whether filtering the receive antenna will be useful. You can also use them to listen to FM radio, hams, airplanes, weather radio, and some emergency services radio.