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Thread: Submillisecond latency RF link

  1. #1
    Junior Member
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    Jul 2019
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    Submillisecond latency RF link

    I need to get a continuous series of values, 2 bytes each, from one teensy to another, wirelessly. The distance is only around ~20cm or so. The constraint is that i'd like this link to have the lowest possible latency.

    I am currently using a pair of nRF24L01 modules, and I get about ~400-500us latency, which is a bit too high for my application.
    As far as I understand, a lot of this time is due to ramp-up and hadshaking etc.
    Is there a simple solution that can get me closer to a 10us latency? It seems like the ramp-up time on the nRF52832 is shorter for instance, but I haven't found any concrete examples for how quickly a very small data packet can be transmitted.

    I'd be interested in more low-tech solutions as well, maybe the fact that this is low distance and we're not limited in terms of battery usage means that a more low-tech radio link could be well suited to this application?

  2. #2
    Senior Member brtaylor's Avatar
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    Silly question. Why wireless when the distance is so short?

  3. #3
    Senior Member+ defragster's Avatar
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    IR transmit and receive? Not sure how fast that is ….

  4. #4
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    That's not silly- the link goes from a rotating part to a stationary one, and there are space constraints that mean I can't easily use a wired protocol over a slip ring.

    And I just need a unidirectional link here.

    Edit: Forgot to specify, i just need this to transmit the 2 byte value at around 5-10kHz so around 80-160 kbps

  5. #5
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    I thought about IR light - but oddly enough I this is for an optics application in which i'd like to stay away from both IR and visible light ..

  6. #6
    Senior Member
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    Jan 2014
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    Did something similar using a high-freq version of NFC (manchester NRZ). Totem-poled transistors (push-pull config) used to directly drive the tank circuit to the antenna.

    So you will have to roll your own on this, or use an off-the shelf radio.

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