RADAR Controlled Speakers

[Scott] had a simple problem – he was tired of leaning over his work bench to change the volume on his speakers. He desired a system that would readily allow him to switch the speakers on and off from a more comfortable distance. Not one to settle for the more conventional solutions available, [Scott] whipped up a RADAR-activated switch for his speaker system.

The build relies on a surprisingly cost-effective RADAR module available off the shelf, running in the 5.8GHz spectrum. At under $10, it’s no big deal to throw one of these into a project that requires some basic distance sensing. [Scott] decided to keep things simple – instead of going with a full-fat microcontroller to control the speakers, a 74HC590 ICΒ was used to create a latch. Each time the RADAR module senses an object in close proximity, it toggles the state of the latch. The latch then controls a transistor that switches the power for the speakers.

Overall it’s a build that combines a modern integrated RADAR module with some very simple control logic to create a functional build. Of course, there’s so much more you can do with some 74-series logic.Β Video after the break.

16 thoughts on “RADAR Controlled Speakers

    1. 1 bit volume control. :-)

      But yeah you could do more, if that was you aim. The trick is to tap into the output from the analogue section of the circuit where the phase shift is converted to an amplitude shift, then use two sensors separated by some distance, this gives you two varying voltages and their relationship encodes the velocity of your appendage relative to both from which you can derive a vector/tensor to feed into a neural network that has been trained to recognise gestures.

      Simple really, if you are a f*ing genius with a lot of time on your hands….

          1. NOT A HACK! Perhaps you should try offtheshelfaday.com otherwise these dirt cheap microwave/radar detectors modules are new (and very on topic) and their potential has not been fully explored by hardware hackers yet. Trying to get more out of them benefits more than just you, if you share what you learn. However if self gratification is your thing…

  1. Cool, but it looked to me like the flat of his hand had to be closer to the sensor than the length of his fingers. At least it didn’t look like it would be an easier reach when seated to me, and possibly worse unless the power switch is in the back of the bar.

  2. If the radar board returned distance information rather than just threshold, you’d have the ability to generate low-cost, coarse-grained radar spatial imaging, as people have done with IR spot thermometers to create simple thermal imaging setups. It’s been done with the ultrasound sensors, but this could get very interesting…

    1. You’d need a time-of-flight module for coolness (~$10).
      The ToF works up to about 1.2m so that should be enough to sense you on your seat. You can then use approaching or receding hand movements to adjust volume.

  3. I read the title and the first sentence and my mind went off to a happy place where the speakers on my workbench always gave my ears the same relative volume level no matter how far away I was from them. Then I read the second sentence. ☠@✴#ing killjoy!!!

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