propeller c sensors

Patrick222122

I am building a robot that integrates Robotics Operating system. I recently converted over to propellor c because this will be very string intensive( as in manipulating strings). However I need information to program and build some of my sensor. I will needing wheel encoders for odometry and sharp Ir senor. How should I build these.

Invent-O-Doc

Yes, I am sure you will appreciate the nice string handling functions in propeller C, though there are not many objects in the stable right now.

I recommend the following for the wheel encoder:

- Research reading an encoder. One of the old 'stamps in class' articles in nuts and volts has a groovy article on this. This was posted on the old parallax site which is still accessible.
There is a nice download here: http://www.parallax.com/downloads/digital-encoder-applications-basic-stamp

- Look at SPIN and PASM encoder readers in the OBEX and use the SPIN2CPP utility to port the object over. If you go this way, and it has worked for me, then make sure to set Simple IDE to "C++" mode to use the converted object.

As far as the sharp IR sensor, I don't know anything about it. Do you have a data sheet?

Patrick222122

I am using a GP2Y0A21YK0F sensor for distance measurements. The link to the datasheet is included bellow.
http://www.parallax.com/sites/default/files/downloads/28995-Sharp-IR-Datasheet.pdf
As a follow up to the last post on this thread, I also need directions on how to build the encoder and wire the GP2Y0A21YK0F(I have yet to see a satifactory explanation on who to wire this specific model). Perferrably in the form of wiring diagrams

NWCCTV

The Data sheet shows exactly how to wire it. What part are you having issues not understanding? Pin 1-Vo, Pin 2-Gnd, Pin 3- Vcc

Patrick222122

I am refeering to this thread here.
http://forums.parallax.com/showthread.php/137220-Sharp-IR-ranger-sensors-and-the-prop?highlight=GP2Y0A21YK0F+propellor It says I should use an ADC. i think you should know that I using the sensor in a poor man Lidar and I think I need exact distance data for it. I do belive that in a pinch I could hard set the range to maximum

NWCCTV

You could use an ADC or follow the instructions to use the delta-sigma way. I will be needing to do this myself here in the next week or so. Will reply with my results.

botninja

In the mean time I need to buy or build optical encoders for my robot. ANy suggestions for low cost solutions.

cavelamb

botninja wrote: »

In the mean time I need to buy or build optical encoders for my robot. ANy suggestions for low cost solutions.

A few links to keep you busy...

http://www.philbot.com/projects/TMG_encoder/

http://www.philbot.com/projects/BOB/BOB-E.htm

http://www.robotmarketplace.com/products/sensors.html

http://www.pololu.com/catalog/category/79

http://www.robotshop.com/sensors.html (very expensive shipping!)
http://www.robotshop.com/encoder-pair-tamiya-twin-motor-gearbox.html

http://letsmakerobots.com/node/29002

http://www.nubotics.com/products/ww02/index.html

http://www.seattlerobotics.org/encoder/200109/dpa.html

http://www.seattlerobotics.org/guide/index.html

http://www.dshinsel.com/components-and-sensors/

http://www.futurlec.com/HardwareMain.shtml

jazzed

Isn't that sensor just an infrared device?

Will it work with dark objects? My experience with infrared was that dark objects (matte black or felt black) were not visible.

You're probably better off with a parallax PING))) sensor.

Patrick222122

jazzed wrote: »

Isn't that sensor just an infrared device?

Will it work with dark objects? My experience with infrared was that dark objects (matte black or felt black) were not visible.

You're probably better off with a parallax PING))) sensor.

Yes I could use the same code I use in the Poor man's lidar with a PING))) or any other 1d rangefinder. I just happen to have the IR sensor left over from a previous project

RS_Jim

Patrick,
The turn around time of a beam of light is faster than the speed of a prop. However if you use the technique of this thread, you just might be able to do it. http://forums.parallax.com/showthread.php/117806-Anybody-played-with-Time-domain-Reflectometer-usin-a-prop.
The velocity of electricity in a cable is lower than that of light so you would have to use different timing constants, but it might be worth playing with.
Edit: if my math and memory are correct, 3.33333333333333e-12 or 3.3 pico sec is 1 mm at the velocity of light.
Jim

botninja

Okay I got the sensors now but two problems have arisen. First I use the parallax compass sensor but inputs the data in xyz elements, how do I convert these to a heading in radians. Also I am using the cytron simple encoder for odometry, however it output the data as pulses how do I read and count these pulses in propellor C?

dgately

botninja wrote: »

Okay I got the sensors now but two problems have arisen. First I use the parallax compass sensor but inputs the data in xyz elements, how do I convert these to a heading in radians. Also I am using the cytron simple encoder for odometry, however it output the data as pulses how do I read and count these pulses in propellor C?

Assuming you are using SimpleIDE, you could look in "Simple Libraries/Sensor/libcompass3d/" where you can find sample code, "libcompass3d.c" which will show you how to use the compass sensor to get headings in radians. That code is a good example even if you are not using SimpleIDE and are just looking for code examples. Documentation is: "Documentation compass3d Library.html" in the same directory.


You'll also find the function "pulse_in (int pin, int state)" if you look into the simpletootls library at: "Simple Libraries/Utility/libsimpletools/". Look for the excellent documentation URLs such as: "Documentation simpletools Library.html" in the same directory.


dgately