IRPD sensor? where can I get one.

Dgswaner

Why doesn't Parallax sell an IR proximity sensor? am I just not seeing it? I hadn't had a need to buy one as I had a few on hand from another supplier, now that I need one I was shocked that I couldn't find one offered by Parallax. I'm not talking about a simple IR transistor circuit. but a modulated 2+ input sensor.

my source has dried up, anyone have a circuit or a source to get a good IRPD sensor?

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"A complex design is the sign of an inferior designer." - Jamie Hyneman, Myth Buster

DGSwaner

Post Edited (Dgswaner) : 12/13/2007 9:31:22 PM GMT

dandreae

We have the·PIR sensor that may work for your project, here is a link for the sensor:

http://www.parallax.com/Store/Sensors/ObjectDetection/tabid/176/CategoryID/51/List/0/Level/a/ProductID/83/Default.aspx?SortField=ProductName%2cProductName



Dave




▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Dave Andreae

Parallax Tech Support

Post Edited (Dave Andreae (Parallax)) : 12/7/2007 5:09:45 PM GMT

parts-man73

.....and, if the PIR will work for you.... it's available now in most Radio Shacks

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Brian

uController.com - home of SpinStudio

PropNIC - Add ethernet ability to your Propeller!

SD card Adapter

Dgswaner

I have a couple of those. What I'm looking for is proximity detection on a mobile robot. An IR LED/receiver pair to detect objects. what I would love is board that would handle 4-6 sensors, that way I could have more input and use some for ledge sensing. But I still think it's weird the parallax doesn't sell one of these.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"A complex design is the sign of an inferior designer." - Jamie Hyneman, Myth Buster

DGSwaner

RDL2004

These people have one:

http://www.lynxmotion.com/Product.aspx?productID=56

Personally, I think it's a bit over-priced but If you download the user guide, it has the schematic, so you could just build your own. There are other ways to do it. Basically you just need one of those 38kHz detectors and an oscillator to drive·the IR LED at the right frequency. If you built your own, you could have multiple emitters and as many detectors as you needed for coverage.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
- Rick

Franklin

also www.acroname.com

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
- Stephen

Dgswaner

I'm opting to just make my own module I can make one for about 1/4 the cost of some places. attached is the schematic that I'm going to use.

I don't have a pic programmer and have never programmed a pic before. My brain is kinda full at the moment and I'd prefer just having someone program them for me. Anyone want to swap, you program some of these for me and I'll make you some PCB's I'll pay for the Pic's

let me know

Added: I have the code already, I just need it uploaded to the PIC.

Removed Schematic it had some errors. see the new one below.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"A complex design is the sign of an inferior designer." - Jamie Hyneman, Myth Buster

DGSwaner

Post Edited (Dgswaner) : 12/13/2007 9:42:40 PM GMT

Bruce Bates

Dgswaner -

Unless I'm missing something here, you're looking for some one to design the program, write it, test it, debug it, give the program away and swap all that time and effort that for some PCB's? If that's correct, I'll be interested to see who "bites" on this offer.

If you already have a program, and you only need some chips "burned" that would sound a bit more fair, but perhaps I over-value my own time <shrug>.

Regards,

Bruce Bates

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔

Dgswaner

dgswaner said...
Added: I have the code already, I just need it uploaded to the PIC.

perhaps I need to bold that. I agree that would not be a fair trade.

all I need is some IC's burned!

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"A complex design is the sign of an inferior designer." - Jamie Hyneman, Myth Buster

DGSwaner

Harrison.

Any reason why you can't use a SX/Propeller/BS2 to do everything the PIC does? It seems that all it does is drive the LEDs and detects to see if the IR sensor module is triggered or not. There is a bit of 'smart' error rejection, but there's no reason that can't be done in another processor.

Dgswaner

The main reason is cost. I admit I haven't priced out the SX route yet, but I doubt I can build the complete SX circuit for under $10.00 which is true for the PIC circuit. I've used this circuit before and it works great. I also don't want to spend time developing a new circuit right now, I'm trying to focus on my current project. I did have the thought to work on a prop or other micro based sensor that would handle 10+ IRPD sensors. this would allow me to have several for object detection as well as some ledge sensing. I have a tall bot and I really need object detection at multiple heights.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"A complex design is the sign of an inferior designer." - Jamie Hyneman, Myth Buster

DGSwaner

Dgswaner

I guess sometimes the best way to get what you want is to just do it yourself. Here is my IRPD sensor. It's not my original design. so I can't take too much credit but I did have to redo the PCB layout and find the part numbers. I'd appreciate a second set of eyes to check it and make sure I didn't connect something wrong.

It has 2 IR LED sensors 5v high/low output for connecting to a mirco. Optional LED's for visually indicating detection . The parts are for a 38Mhz IR reciever but with a simple code change it can use 56 kHz so 2 units can be used side by side with out interfering with each other. All that for only $9.74 from mouser.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"A complex design is the sign of an inferior designer." - Jamie Hyneman, Myth Buster

DGSwaner

Post Edited (Dgswaner) : 12/13/2007 9:35:09 PM GMT

RDL2004

I'm going to need one (or more) proximity detectors for a future project and I'm curious as to what advantage this circuit has over the one used by Lynxmotion? It appears they do pretty much the same thing, this one using a PIC that has to be programmed while the Lynxmotion circuit uses a 39 cent logic chip. Am I missing something? It seems like all that's needed is something to take over the job pulsing of the IR LEDs so that the Stamp (or other controller) can do other things and just check periodically for high/low from the detector.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
- Rick

Dgswaner

like I said, I didn't design this. But I know it works, and it works well here is what the designer has to say about it.

"The IR proximity detector works very well, even in a brightly lit "noisy" environment. Instead of modulating the IR LED for 600us and then looking for a detection, I now look for a detection after every on/off cycle of an IR LED and count the number of hits that I get. I also look during the 'off' cycle when none of the IR LEDs are on and count the number of false hits that I get there. If I get more good hits than false hits then I say its a true detection. I then increment a counter as a sort of timer, when it passes a certain threshold, I notify a hit. At this time I check to make sure that a minimum number of good hits has been attained. At the same time I keep track via another time-out counter of noise hits. When this counter passes a certain threshold it then removes any detection that has been set. I fiddled a lot with the various threshold values for minimum number of good hits, time-out values and divisors for updating the false hit counts, and finally settled on the ones that currently used." -- Dennis Clark

I'm not trying to sell you on this circuit. but if your referring to the Lynix motion sensor listed above, than it appears to have a PIC that is programmed, and appears to be quite similar to this design. except that it costs 3 times as much. I like the do it your self approach, when ever I can.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"A complex design is the sign of an inferior designer." - Jamie Hyneman, Myth Buster

DGSwaner

Post Edited (Dgswaner) : 12/16/2007 7:11:34 AM GMT

bulkhead

Seems to me like the extra 200% over the cost of parts comes from the time spent finding those "threshold values," among other things (design, testing, production, marketing, support). Time is money...

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
I'm new to the propeller!

Dgswaner

well.... fortunately that's already been done! so his time wasn't my money! I feel like I'm defending this circuit over the other... so I guess my final words will be don't like it... done use it.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"A complex design is the sign of an inferior designer." - Jamie Hyneman, Myth Buster

DGSwaner