IR Detectors

liljoentx

P238 of the Robotics with Boe-Bot show pin 1 going to Vdd, pin 2 to Vss, with pin 3 being the signal out, yet a schematic in the IR Object and Distance Detection Circuits labeled Schemtic - IR Distance Circuit.spin shows a totally different arrangement with a 10K resistor developing signal off of pin 2 and pin 1 going to +5 volts and 3 going to ground (Vss). The PNA4601M.pdf datasheet show yet a third pinout qwith Pin 1 assigned to Vout, pin 2 called out as GND and pin 3 defined as Vcc. The diagram also shows a rather different case, than the ones I was sent in the Boe-Bot Parts Kit (#28124) with a large numeral 3 stamped on the detector face side and OM31/07419 /12AHH printed d on the back side. In the IR Decoding and Detection appnote.zip for the current IR detector (#350-00014), the pdf file titled "Weekend Special - IR LED & 40 kHz Detector.PDF", Figure 1.1 has another rather ambiguous schematic.

Can someone please enlighten me as to what the circuit should look like and what the correct pin outs are?



Thanks!

Philldapill

FYI, Vcc and Vdd are essentially the same thing. Vdd is the "Drain" supply(for mosfet based circuits), which is positive, and Vcc is "Collector" supply for transistor based circuits. Also, Vss and Gnd are the same for the most part. Vss is the "Source" for mosfet circuits, and Gnd is well, gnd in everything else(negative.

deSilva

When you got a receiver with this descriptive "3" on pin 1 in a metal case the pinout is:

(looking at its eye)
left: 1 data-out (tagged with "3")
middle: 2 GND
right: 3 Vdd +3.3 to 6 V


See enclosed some other animals of that "zoo"

Post Edited (deSilva) : 2/24/2008 12:23:10 AM GMT

Oldbitcollector (Jeff)

@Desilva: Do you mind if I add that graphic to the existing IR documentation in the Cookbook?

OBC

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deSilva

This is a darn silly question
You have the expressed permission to add all my postings into your cookbook


Edit:
Maybe you should also include this image from some datasheet (they are all the same) showing what a complex device such a receiver is...

Post Edited (deSilva) : 2/24/2008 1:51:15 PM GMT

liljoentx

Thanks, deSilva!

That pinout collection will be helpful also. Apparently Parallax has changed this device a couple of times.

Good for you, OBD, on keeping us all better informed.

That block diagram is from the IR detector (#350-00014) downloads on the Parallax website:

http://www.parallax.com/Portals/0/Downloads/docs/prod/audiovis/PNA4601M.pdf

What is the recommended method of biasing this critter? I've noticed everything from 3.3 to 10 volts and resistances, placed between the output and the selected Prop input pin of 220 to 10K ohms. Not being a whiz at these devices, I can only imagine it has something to do with the sensitivity or amount of output signal one wishes to generate. Please advise.

Oh yes, Philldapill. Thanks for your input, too, but it didn't answer my question! My description was taken directly from the various articles where I had garnered all of the confusing information and was intended to illustrate why I found them confusing. Electronic references such as·Vcc, Vdd and Vss are understood by me and have been for the 50 years I've been in the computer world. I am just attempting to get some form of standardization to the documentation·referring to·and supposedly supporting·all of our·use of this device in our hobbyist circuits, especially those·being built by less proficient amateurs! I might also point out that your comment was not only rude, but could tend to make the issue even more confusing for the average hobbyist!

Lil'Joe (6'7", 260#)

deSilva

There is no need to put anything between the sensor output and the Propeller when you power it with 3.3V which generally works fine.

As these devices are rated downto 5V only you might find it safer to power it from 5V, which then needs an additional current limiting resistor for the Propeller connection. It's value is somewhat arbitrary due to the low frequency... 1k is fine, but 10k will also work, or anything in between...

liljoentx

Thanks, much obliged!

Oldbitcollector (Jeff)

Added to the Cookbook..
www.warrantyvoid.us/addingirsensor.html

OBC

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
New to the Propeller?

Getting started with the Protoboard? - Propeller Cookbook 1.4
Updates to the Cookbook are now posted to: Propeller.warrantyvoid.us
Got an SD card? - PropDOS
A Living Propeller FAQ - The Propeller Wiki
(Got the Knowledge? Got a Moment? Add something today!)

IronIngo

Just wanted to mention that there is a difference between the IR detector shipped with the BOE-BOT kit (OM31-07419-12AAH) and the more contemporary PNA4601/2M.

The OM31 detector seems to "throw away" any signal that appears to be too "even", for instance a continuous IR signal or a fast-pulsed IR signal, say 1ms on and 1ms off.
The PNA4601 does detect those signals properly.