Devantech's SRF04 or SRF05?

[JavaRN]

I would like to experiment a little with sonar sensors. I don't have a nice experience with them as the MaxSonar I have is behaving quite erratically reporting false readings.

What do you suggest I buy SRF05 or SRF04? Have anyone tried these with robonova? I've just installed i-bot's flash upgrade to be able to work with speech module SP03.

Does anyone know why the MaxSonar sensor is behaving erratically? What is your experience with MaxSonar?

Thanks

Charles

[i-Bot]

I have played with the SRF04(SONAR command), SRF02(I2C), and the MaxSonar(Analog), and not found much performance difference. The MaxSonar should be the easiest to use on the Robonova, and has lowest software load, since it is an analog input. The SRF04 is obviously bigger due to separate TX and RX transducers. Note: the SRF04 need to be powered by 5V (top row of connectors), though it uses servo singal from the side connectors.

As I said I have played with these, but not actually used them within RoboBasic motions.

When you say eratic behavior for the MaxSonar, is this when installed and moving ?

I have found all the sonar units to be very sensitive to placement, height, angle and to their beam width.

[PeterW]

I had a bit of a play with sonar devices when working on minisumo and the problem I found was the range was too big and you get all sorts of reflections off the walls of the room. Once you limit the detection time down to the range you require and wait long enough for all the reflections to die away before using again it settled down a bit. I can't remember how long I set it for as I eventually used IR sensors.

[davidalecmcinnes]

I went for the SRF05 as it's a low current version of the SRF04. I had all sorts of problems using the servo commands in robobasic so I used the 78.5Hz servo signal as an activation pulse and fed the response into a 5Hz 3rd order low pass filter to generate a dc level for the AtoD. Like all sonar they have a wide viewing angle and benefit from having a tube fitted to the emitter or receiver, can't remember which one; makes him look a bit like a Borg.[/img]

[DirtyRoboto]

As an analogue sensor the Maxsonar is logarithmic meaning that at great distance it has more resolution then at close distance. See the routine I posted that plays a tone as the sensor reading changes. (robotheramin).
I like the AD sensor as a cheap and fast additional input but I would now look for an digital solution if I were relying on the input.

Dirty.

[criadobot]

Hello group! I would like to issue something more about the implementation of the ultrasonic sensor SR05, or if you have any reference of how to do it, because I have a strong interest in implementing a sensor of this kind in my Robonova.

http://www.criadobot.info/noticias/Robo ... Cabeza.htm