NQC ("Not Quite C") : 1804


Robotics / RCX / NQC / 1804	1803 \| 1805

Subject:	IR-based proximity measurement
Newsgroups:	lugnet.robotics.rcx.nqc
Date:	Fri, 16 Sep 2005 07:03:06 GMT
Viewed:	6293 times

I'm changing the subject line in the middle of the thread. Wonder what the server will do with that... I tried out Brian's "Max-picking" ping method, as well as a few other things. Here's a summary of what I found: 1) If the active sensor readings are averaged to improve the signal to noise ratio, then using SendSerial() to send 16 continuous bytes of 1's through the IR Comm port works better than using SendMessage to only send one byte. Not too surprising. I reckon the SNR is around 2-4 at best, using any of the averaging methods I tried. 2) If Max-picking is used instead of averaging, the SNR gets (finally!) adequately high, around 7-8 depending on how you eyeball it. This is a really great idea, and the more I think about it the more I appreciate why it works so well in this situation. My calibration code beeps with a pitch proportional to the estimate of proximity, and I can pretty much tell how far away from the wall the bot is just by listening. I put the code and some calibration figures here, if anyone's interested: http://www.physiology.wisc.edu/jones/robotics/proximity/SerialPing.nqc http://www.physiology.wisc.edu/jones/robotics/proximity/SendMessagePingAvg.jpeg http://www.physiology.wisc.edu/jones/robotics/proximity/SendSerialPingAvg.jpeg http://www.physiology.wisc.edu/jones/robotics/proximity/SendMessagePingMax.jpeg http://www.physiology.wisc.edu/jones/robotics/proximity/SendSerialPingMax.jpeg Cheers, Matt

Message has 1 Reply:

		Re: IR-based proximity measurement
(...) i have downloaded the SerialPing.nqc program hoping to get an easy to use proximity sensor. i have modified it to work with only one light sensor. but it shows always -90 on the display. ok, sometimes -89 too. can anybody tell me, what i did (...) (18 years ago, 9-Jun-06, to lugnet.robotics.rcx.nqc)

Message is in Reply To:

		Re: direct manipulation of bits in RCX registers using NQC
(...) Correct. A NQC command (say, "Wait(10);") is converted to one or more "bytecodes" (in this case, one bytecode, namely a string of 4 bytes (0x43 0x02 0x0a 0x00), the first of which is a command (0x43) while the following three are information (...) (19 years ago, 16-Sep-05, to lugnet.robotics.rcx.nqc)

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