Reflective Sensor with Atom Pro 40M?

Lynxmotion Electronics & Software
1

Hey,

I have a pololu qtr-1rc reflective sensor that is supposed to be capable of edge detection, but I’m somewhat confused as to how I would use it. Would anyone happen to know of any example code for it?

Thanks!

robotshop.ca/pololu-qtr-1rc- … sor-1.html

2

Sorry, but I am not sure what your question is. Are you asking how would I mount it? What would I try to detect with it? How to wire it up? Or how to program it with the Atom Pro 40?

I will assume you are asking how do I write a program to use it. What have you tried? If it were me, I would start out hooking one up to my processor and try to get some readings from it. I would probably start off using the RCTIME command to see if that worked well enough for me. Start off with some simple program like:

[code]dtime var word
dtprev var word

dtprev = 0

main:
high P3
pause 10 ; wait for capacitor to charge…
rctime P3,0,dtime
if dtime <> dtprev then
serout s_out, i9600, [dec dtime, 13]
dtprev = dtime
endif
goto main [/code]

This assumes that your sensor was on IO line P3, change to whatever pin you wish. Also note, I typed this in so may not compile…

Now assuming this works, I would then move the sensor over the different surfaces, like off the line, near the line and on the line to see what the differences are in the values. Then I would calculate a threshold and then write the rest of your program…

Good Luck
Kurt

P.S. - I wrote this program like I would for a Basic Pro 28 (BAP28). For a Bap40, I would probably replace the serout s_out line, with an HSEROUT command with the appropriate init code to initialize the hardware serial port.

3

The sensor has a TTL output be default, I would try to get it working first. :wink:

Edit: I made an incorrect assumption. It appears that the normal way to use this sensor in TTL mode is to use some goofy RC time comparison. I would run away from this sensor. There is just no reason to complicate this sort of sensor that way. Sorry…

4

Ok, so it seems it would just be somewhat the same as what I would do for a reflective sensor. Set some pin to be high, pause for 10us, and then use rctime to see how long it takes to get the signal to change.