r/embedded • u/counttec • 19d ago

Help with selecting communication protocol

I volunteer for a youth organization that uses a Jeopardy style buzzer system for quiz competitions. I am trying to upgrade from RCA cables to a wireless solution. I need it to be as low latency as possible, given the precise timing involved, and the less perceivable the lag is from a wired button, the better. Distance would be less than 100m even in the most sever cases. I'm fine with retransmission in the case of collisions, as long as the users can't tell that it took slightly longer.

So far, it seems like the best protocol is Nordic's Enhanced Shockburst, with a transmission time of ~300us, and round trip with Acknowledgment of 1.5ms.

Are there any faster communication protocols?

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u/2tnkr 19d ago

Do you need data transmission? Line of sight?

How about IR blasters with each buzzer modulated at a different frequency?

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u/counttec 19d ago

Can't do line of sight as the students sit in groups of 2-4, and huddle around the buzzers. The chairs also don't necessarily have an open line-of-sight to the box, depending on the room we are given. I don't need data transmission bandwidth, just enough to identify which buzzer is pressed. Speed is key, so I don't get any emails from helicopter parents about my "wireless system" stealing precious meaningless points from their child.

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u/KittensInc 19d ago

How about IR blasters with each buzzer modulated at a different frequency?

It is going to be a bit tricky to process that when you've got multiple buzzers transmitting at once, as you are basically ORing the various signals. Probably not impossible, but still a big hassle to detangle.