about ultrasonic range finders

hello,

this has probably been previously discussed, yet i wasn’t able to find the info i need via a forum search.

how many Ultrasonic Range Finders can be simultaneously connected (and active) to a single arduino board?

thanks,
k.

It depends what sort you use.
Some are connected via I2C, and I’ve seen up to eight on a bus (SRF02 from Devantech).

thanks for the reply.
i’m considering two different applications:

  1. i have a tabletop surface, about 60x30cm, and i want add an audio-reactive feature to it. meaning, whenever you move your hand / place an object on the surface, the rangefinders will send distance values to the board which will be converted into sound.

  2. i’m looking for a solution combining a few sensors, which will allow me to perform angular proximity sensing. say i have an object placed in the middle of a room, i’d like to simultaneously measure the distance between the object and the ceiling, and the four different walls surrounding it.

will appreciate any advise.
thanks,
k

Tricky - you don’t say how big the objects, or how much clutter there is in the room, or what sort of update rate you need.

One of the problems with ultrasonic rangefinders is multiple echoes - if you just fire all the sensors at once, they’ll potentially pick up echoes from pulses transmitted by other sensors, making it impossible to distinguish them.

It is possible to fire them sequentially and wait until all possible echoes have died away, but this reduces the overall update rate.

(I just checked the Devantech website - the SRF02 supports up to 16 devices on a single I2C bus)