I want to build a little array of 3 Ultrasonic range finder.
They should aim into 3 different directions, so they are not interfering to each other. Also, I want to measure the range for all three continiously and at the smallest available interval as possible.
I recently have bought these parts:
(English specification in second part of document)
Both devices have similar minimum ranges (around 6"/15cm), presumably because they both use a single transducer for transmit and receive, so you have to allow a short settling time after transmit to allow the transducer to stop ringing.
There should be no problems using either (or both) with an Arduino.
I've not used either, but have used another Devantech device, and it has proved very reliable.
The MaxSonar claims up to 20 readings per second, whilst the Devantech appears to manage only about 15 readings per second (65ms between pulses).
It looks like both devices will detect all the way down to zero range, but only provide range information from 15cm or greater.
In my experience, maximum range is rarely a consideration.
Thanks a lot for the great feedback!
I have only one question left:
Do you think, that the output method (Serial, I2C, Analog voltage, pulse width) does somehow affect the detection interval?
Usually the limiting factor for update rate is the maximum range of the device.
There's no point in sending out a pulse until you're certain that the echo from the last pulse won't be detected.
If the maximum range is 6 metres, that's a round-trip of 12 metres. Say the speed of sound is 330ms-1, that gives you a maximum update rate of 330 / 12 = 27 readings per second.
Both the sensors mentioned fall a little short of this.
The connection method won't normally be a limiting factor, unless you put too many devices on a single serial interface.