A Speaking Ultrasonic Distance Sensor


[Klaus] wanted some sort of aid for parking his car, and after running across a $4 ultrasonic sensor, decided to build his own speaking distance sensor (.de, Google Translation).

Inside [Klaus]‘ device is an Arduino Uno, an HC-SR04 ultrasonic distance sensor, and an Adafruit Wave Shield. Originally, this parking/distance sensor used a small TFT to display the distance to an object, but after a few revisions, [Klaus] redesigned the device to speak the current distance, courtesy of an SD card and a soothing female voice.

Right now, the voice is set up to speak the distance from an object to the sensor from 10 cm to 1 m in 5cm increments. This isn’t the limit of the sensor, though, and the device can be easily reconfigured to sense a distance up to four meters.

The board doesn’t have an amplifier or speaker, but with the addition of a small amplifier, [Klaus]‘ device is loud enough to be heard in even the noisiest environments.

Video demo below.


  1. vonskippy says:

    Worth watching the video just to see his “Bat Detector”.

  2. Alan says:

    I have been “disappointed” with ultrasonic reverse warnings – ever since I [almost] ran over my wife.
    While reversing out of my garage, the warnings were tripped – as usual – by the proximity of the garage door frame. So – as usual – I ignored it and kept going. Unfortunately, my wife chose that exact moment to DUCK DOWN, behind the car, to pick up some errant piece of garbage. She is only alive because I glimpsed her moving forward: once she bent over, she was invisible from the driver’s position.
    We had words after that. And my next car will have a reversing CAMERA.

  3. StinkySteve says:

    Buy arduino, buy sound shield, buy distance sensor shield, plug into each other, burn example code, stuff components inside box.

    Not only is this not a hack but he might as well have just bought a proper $15 reversing sensor kit off eBay. He’d have got 3-4 sensors and a little LED/beep display to be placed on his dash.

  4. Hey!! I also made a similar thing few weeks ago http://www.youtube.com/watch?v=yvETULMAfCc , I used a voice IC instead

  5. Whatnot says:

    The video reminds me of good classic scifi movies, something about the voice/pronunciation.

  6. Remarknl says:

    The board does have an onboard amplifier, its just not that loud. A cool hack is to stack another amplifier chip of the same type on the original. Like this: http://learn.adafruit.com/halloween-pumpkin/step-1

    • Remarknl says:

      I had the same volume problem. Apart from this hack i matched the speaker the best i could. Apart from the ohms i matched the watts. If the watt output is close to the maximum watt rating of the speaker, the speaker will work more efficient. I dont know the theory, but this is what i found out through testing. Another way to improve volume is the case. Mount your speakers in a sturdy case in a non flexible way. This way the case will work better as a sound box.

    • tekkieneet says:

      They are using an opamp limited to 80mA drive for line level output
      instead of an amplifier designed for a speaker e.g. LM386.

      So the output drive current is limited to 80mA ^2 * 8ohms = 50mW. You
      might get higher power by using a high impedance speaker e.g. 32 ohms

  7. Anyone know where to get a rotary disk potentiometer like the one in this project? I’ve been searching for months for one for a project, but no-one makes them any more. Sparkfun carry one 40K one I think, but other than that I’m stuck.

  8. strider_mt2k says:

    More than one meter
    More than one meter
    More than one meter
    More than one meter

    Where did you learn to fly?

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