IR Sensors help

Special_K · 2006-02-01 05:39

Hello,
I am looking to expand functions my Boe-Bot. I have noticed that my IR Sensors (the ones that came with the Boe-Bot kit)·will get different reading depending on the slant of the IR LED and IR Sensors. I found this all-in-one unit online. Will it work? And how will I connect it to the Boe-Bot bread board and program the Boe-Bot to receive its inputs since there are only two pins on the IR Sensor.
http://www.sparkfun.com/commerce/product_info.php?products_id=246

Andy Lindsay (Parallax) · 2006-02-01 05:50

This is a very close range sensor that is designed to be used to detect the black and white stripes. Works great for encoders and line followers. The QTI Sensor·uses an almost identical device (the QRD1114). The QTI sensor product page has a PDF with the circuit. However, I think the QTI sensors are much easier to use, and extremely useful for Boe-Bot projects. The QTI Line Follower AppKit·uses them for line following, and with the extra mounting hardware, it's·definitely an effective way to "expand the functions of your Boe-Bot."· Another example, the SumoBot Competition Kit·uses them to detect the edge of the white edge around the black competition ring.

Probably the most common way this circuit is used is as an encoder, which you can use to count how many holes in the Boe-Bot's wheel has passed by the sensor.· You can also use QTIs for this, or the·Boe-Bot Digital Encoder Kit, which has some extra features.·

BTW, the sensor has four pins.· For encoding, a series resistor has to be added to the pins connected to the device's IR LED, and a 10 k pullup resistor is typically connected to the device's infrared phototransistor.· I'm out of time tonight, but I'm sure that there will be schematics posted to this thread that show the circuit before noon tomorrow.

Post Edited (Andy Lindsay (Parallax)) : 2/1/2006 6:08:24 AM GMT

Special_K · 2006-02-01 06:07

Ok,
So the QRD and the QTI are similar (close range). Is there a unit that has the same function and range of the IR Sensor and IR LED (that come with the Boe-Bot kit) that is an all in one unit?

Andy Lindsay (Parallax) · 2006-02-01 06:15

Parallax used to carry the SSIR detector, but it was discontinued. I don't know of any. Keep an eye on this thread though, somebody else might have a link for you. Google might turn up something too.

For improved Boe-Bot object/distance detection, I prefer the PING)))™ Ultrasonic Sensor and the PING))) Mounting Bracket Kit.· It might not be infrared, but ultrasonic is way better and certainly worth a look.· The Ping))) sensor only uses 1 I/O pin, and you can perform a 180-degree sweep with it and the servo mounting bracket.

Post Edited (Andy Lindsay (Parallax)) : 2/1/2006 6:28:44 AM GMT

Special_K · 2006-02-01 06:29

I wanted to use ping))) for front and back sensing and 4 IR sensors down the side to help in close quarters navigations.

LoopyByteloose · 2006-02-01 15:30

These sensors could be used to either follow a line or recognize a ledge. In either case they would be pointed straight down and be very close to the surface [noparse][[/noparse]say about 1/8"]. You need that to get a strong IR reflection.

Looking forward or to the sides, they likely won't help and bumpers would be a better alternative.

I wonder if you really need a Ping to the rear. After all, you know where you have been.

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Tom Walker · 2006-02-01 18:03

Kramer,
...unless you are turning while backing up (a common response to an obstacle in front of you)...

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Post Edited (Tom Walker) : 2/1/2006 6:06:55 PM GMT

Special_K · 2006-02-01 18:14

I was thinking about the turning while backing up, but also turning in a space that is almost the same size as the Boe-Bot. I wanted to be extra sure it would not hit the walls.

Special_K · 2006-02-01 18:47

Ok I need to use touch sensors will these do.
http://www.sparkfun.com/commerce/product_info.php?products_id=98
Parallax has a touch/bump sensor but is says it is for the toddler

Bruce Bates · 2006-02-01 22:41

Special_K -

Nearly any microswitch will do what you need for it to do, with an appropriate "whisker" attached. The Parallax "Twinkle Toes" are a bit much for your needs, and were specifically designed for use with the toddler, a walking, rather than wheeled or crawling, platform.

The unit from SparkFun should be fine. You can also purchase microswitches from almost any electronics surplus house for a dollar or two.

Almost all microswitches have three terminals: COM, N.O. and N.C. Thus, you can optionally use these switches in normally open or normally closed circuits, depending on how you want to wire up your sensors, and how you choose to detect thier activation. COM is obviously the common terminal, used in either case (open or closed circuit wiring/sensing).

Microswitches also come with different length and different shaped actuators. For my money, within limits, the larger the actuator, the easier it will be to properly attach a "whisker". Here is one I've used before, quite successfully:
http://www.mpja.com/productview.asp?product=14426+SW

Regards,

Bruce Bates

Special_K · 2006-02-03 04:26

would this unit work ??
http://www.acroname.com/robotics/parts/R19-IR02.html
It is an all in one IR sender / receiver. I think it is what I was looking for.

Andy Lindsay (Parallax) · 2006-02-03 06:02

Yes.· You will need two I/O pins to operate the device, and it works just fine with the BASIC Stamp.

Post Edited (Andy Lindsay (Parallax)) : 2/3/2006 6:05:15 AM GMT

IR Sensors help

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