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Progress - er, at least using my head.
I have found a way to make short, 10 to 80 usec pulses while using the 4mhz oscillator. The SRF05 proximity detector wants at least 10 usec. If I give it super long pulses catching the following echo measurement can be a problem for PULSIN.
Sooo the following makes an 80 usec positive pulse.
SYMBOL trigright = PORTB.0
LOW trigright
HIGH trigright
HIGH trigright
HIGH trigright
LOW trigright.
One thing at a time.
Ken
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speed is elusive.
I now have the sonic ping devices (SRF05's) flashing continuously. There is no blockage in the PIC's processing.
Now the car is reacting too quickly. There is a bit of code that used to guarantee a 1/2 second backing up when backing up was necessary. Now the count down for this delay is instantaneous. While turning a corner the proximity sensor data gets confusing. Both the side sensors and the forward sensors are hearing important echos. I might need to adjust the positions of the two SRF05's or write some code especially for that situation. I am not sure - elusive. Like I said.
Ken
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Hope you are not activating both sensors at the same time, right? Be sure to give some time for the echo to decline enough before confusses the other sensor.
Ioannis
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No, but I never thought about echoing echos
I've added a PAUSE of 1/10sec between the front trigger and the side trigger. This noticeably slows down the flashing of the LEDs on the SRF05s. In the audible range I can easily hear echos in a room. I have no experience with ultra-sound in the range that the SRF05 emits. The spec shows a time line in which the pulses seem to be a square wave of 2usec cycles. That is a little burst of 500,000 cycles per second sound that appears to last about 20 usec.
This little project keeps gets interestinger and interestinger!
If there were five cars racing near each other on this gymnasium track, would their SRF05's get confused. I don't think so, but I am not sure....
Ken
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They SURE would. That is what I noted on my previous post. Your sensors are hearing echoes that keep coming long after the transmission stopped. No matter which of the SRF05's did the transmission. Keep note of that.Originally Posted by Kenjones1935
If there were five cars racing near each other on this gymnasium track, would their SRF05's get confused. I don't think so, but I am not sure....
Maybe an IR sensor would be more appropriate here. Also faster.
Ioannis
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A product suggestion would be greatly appreciated.
If I went with IR proximity sensing, the reflections would be from brick, wood and cardboard. Distance one to five feet should do it. Any suggestions?
Ken
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I have not used them, but here is one that is within your measurement range GP2Y0A02YK:
http://sharp-world.com/products/devi...gp2y0a02_e.pdf
One thing that isn't so good, is that you will get a false reading if you are closer than 8 inches.
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They're on 2mm (0.079") centers.
Digikey has a whole variety of them. Here's one flavor with 12 pins, right angle.
http://search.digikey.com/scripts/Dk...me=S5802-12-ND
Steve
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