@Robotics Developer: ...sequencing of the ultra sonics (say left, back, front, right) to prevent echos from interfering...
Agreed -- in fact we are thinking of givng the sensor boards the ability to automatically keep on performing a "round-robin" ping one after the other and to kep on doing it -- whenever the main processor is ready (or interested) it can simply request of any senso "what was your last reading?"
@Sanjib.A: Btw...why did you chose urtrasound over Infrared? What is the min-max distance directed?
No particular reason -- I was planning on using infraed sensors under the robot to detect edges (like if you put it on a table) -- I've never played with ultrasonics before, so I decided to go that way -- as I recall, they are upposed to be accurate from 2cm to about 450 cm.
@Max & Duane:
Thank you for sharing your project ideas. I was looking for a cheap but fairly accurate ultrasound sensor for a different application (water level measurement of the overhead water tank of my house). I am going to check this out.
Btw...why did you chose urtrasound over Infrared? What is the min-max distance directed?
Max, the other thing I would remind you of is the sequencing of the ultra sonics (say left, back, front, right) to prevent echos from interfering. This is more of an issue with multiple robots in a common environment but the side effect is to reduce the processing overhead to 1 or 2 sensors at a time. The other programming feature that would be nice is to increase the polling on the sensors that are closing in on an object to keep from hitting it. All that said, it would be most helpful if you had touch bumpers all around to protect your furnature.
Max, regarding the ultrasonics make sure you test out the environment that you want to run them in. In robotic competitions we "saw" problems with utrasonics and diamond plate. It seems that with diamond plate the ranging varied greaty due to weird reflections. Be save and test out the environment.. also could be a nice article to write up for others to learn from your experiences.
I did very much enjoy the pun :bouncing back and forth"!! Keep up the puns..
@Max..."I think the on-board electronics on the '04 are just for pulse-shaping/controlling the out-going "ping" and detecting/registering/noise-filtering the incoming response..."
From the timing diagram in the datasheet, when you give it an initiate pulse the module will send out 8 40KHz pulses from the transmitter. Immediately on completion of that it starts the Echo pulse - which it would appear carries on until it detects the end of the echo - that's the pulse you time with your MCU.
The pulse (by my calculations) is 6.4 CM long....yet the unit can measure down to 2 cm. I guess working off the trailing edges of the pluses lets it do this. Quite clever.
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