# IR LED Signal circuit help



## BrokeCurmudgeon (Feb 8, 2016)

Some days my old mind works and other days it doesn't. Would someone tell me why that there are 2 ir tx's and 1 ir rx associated with each led (green and red)? Also, why are there 2 of the associated detectors? 
I am losing my ability to understand even the most basic electronics even thought I worked in the field and even have a FCC General Class Radiotelephone License. I bought his unit from China on the cheap but it didn't come with instructions.
Your help and understanding will be greatly appreciated!:appl:


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## DonR (Oct 18, 2012)

I can understand your frustration.

Is this some sort of infra red detector that you
would use for signal or other control?

You could damage something just hooking it up
to the wrong power supply. Who knows what input
voltage it would require, probably less than 5 v (DC?).

It looks like what I see as red and purple wires that seem
to be the power in. I suppose those various dark wrapped or
dipped items with wires in and out are various electronic
components. Are the two small tubes in mid right the
detectors...I see the IR red lamp.

If you cannot get the instructions from the seller your
best hope would be to luck up on the find of a member
who has one.

I doubt that a guy with an FCC first class engineer license would
figure that one out. Of course a little testing would help
but I would fear damage since the input voltage is unknown.

Don


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## gregc (Apr 25, 2015)

what are they for?


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## BrokeCurmudgeon (Feb 8, 2016)

gregc said:


> what are they for?


A red green signal mast.


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## BrokeCurmudgeon (Feb 8, 2016)

DonR said:


> I can understand your frustration.
> 
> Is this some sort of infra red detector that you
> would use for signal or other control?
> ...


Thanks Don! I got my FCC License about 50 years ago. Much water under the bridge. For the majority of my career I was in management and didn't have to think too much.:hah:
There appears to be one detector per led (red and green) and 1 emitter. Thus 2 of each configuration. But I am still not sure and as I said, there are good days and bad days. I seem to be slipping into a fog...:smilie_daumenneg: I suppose that it works like a block detector. Once a loco is in between the two detector maybe the red or green led comes on. But, then again, I am not sure. I am hoping that someone will instruct me as to how to install this unit.:dunno:


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## BrokeCurmudgeon (Feb 8, 2016)

DonR said:


> I can understand your frustration.
> 
> Is this some sort of infra red detector that you
> would use for signal or other control?
> ...


I hooked up 12vdc to the red/black leads and the green led came on. No yellow nor red. But after trying to move all the other leads to whatever possible proximity, nada!!! :smilie_daumenneg: Still hoping for someone to figure it out.hwell:


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## BrokeCurmudgeon (Feb 8, 2016)

I got looking closer and found 2 led's that were stored inside of a shrink wrap tube. One was clear and the other was black. After pulling them apart I can get all of the signal led's to operate. Now, I am even more confused. What are theblack devices associated with the round device? Help:dunno:


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## BrokeCurmudgeon (Feb 8, 2016)

Finally got seller to respond. Now all I have to do is understand his directions.:hah: Link is for Ebay item of what I bought. Thanks all!:appl:
http://www.ebay.com/itm/162139525784?ul_noapp=true


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## gunrunnerjohn (Nov 10, 2010)

The instructions look fairly clear, what part are you having trouble with?


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## BrokeCurmudgeon (Feb 8, 2016)

gunrunnerjohn said:


> The instructions look fairly clear, what part are you having trouble with?


Thanks John! :smilie_daumenpos: I was hoping that you would offer an opinion. Initially I didn't have any instructions and the ir leds were hidden in shrink wrap. The only things visible were the ir detectors (?) in the little tubes. Now I can see how everything goes together.
My problem lies with the horizontal placement of the ir led's. I would prefer them to be between the tracks. As I have stated, my mind is getting a little clouded some days. So I am struggling with what should be basic.:smilie_auslachen:


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## gunrunnerjohn (Nov 10, 2010)

Well, I see the source of confusion. That unit appears to be designed to project across and sense an object between the sensor and the IR emitter. I think you are wanting to use a reflective sensor that bounces the IR off the object and back to the source where the receiver is located. That's akin to the Lionel 153IR and similar detectors.

Part of my confusion was that you only showed a low resolution shot, so I had no idea what it was actually supposed to do. I didn't recognize the signal in the middle, so I figured to wait until more details emerged.


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## BrokeCurmudgeon (Feb 8, 2016)

gunrunnerjohn said:


> Well, I see the source of confusion. That unit appears to be designed to project across and sense an object between the sensor and the IR emitter. I think you are wanting to use a reflective sensor that bounces the IR off the object and back to the source where the receiver is located. That's akin to the Lionel 153IR and similar detectors.
> 
> Part of my confusion was that you only showed a low resolution shot, so I had no idea what it was actually supposed to do. I didn't recognize the signal in the middle, so I figured to wait until more details emerged.


The provided photos are not high def and are difficult to read. Further my question: Why are there two ir leds, one black and one clear. Also, the provided photos show some of the parts, ie. ir tx and ir rx not connected. Mine are. I have set up a mockup but I can't get it to work as described. That is, the yellow led and the sequencing of led's as the loco enters (green, yellow and red). I don't want to impose upon you and your technical knowledge but if you feel like commenting, I would be more than happy! In the mean time, I will continue to tinker with the mockup.


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## BrokeCurmudgeon (Feb 8, 2016)

I know that I am not as smart or bright as I once was. :smilie_auslachen: I also know that when you "buy on the cheap" from China, you get what you get. I have tried to get this thing to work by using their poorly written instructions with unreadable photos but it doesn't do as they describe.:smilie_daumenneg:
I have given up and I will only buy American made products in the future. Companies such as Azatrax. Even though one may pay more, the quality and support cannot be beaten!::smilie_daumenpos:
The sweetness of low prices are soon forgotten after the bad taste of poor quality and service are experienced. :appl:


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## gunrunnerjohn (Nov 10, 2010)

This is probably one of those things that you just have to tinker with to see if you can get it working. I've had plenty of successes with Chinese stuff, and some disappointments as well.


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## deedub35 (Jan 29, 2014)

I have similar looking components for my crossing signals. What looks like a black LED is the infrared transmitter. What looks like a clear LED is the infrared receiver. They are mounted across the track from each other and point at each other. The wires are attached to a circuit board. When the circuit board is energized these components produce an infrared beam across the track. When the beam is broken by a passing train then it activates my crossing signals.


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## gunrunnerjohn (Nov 10, 2010)

Hmm... Usually the black component is the receiver and the clear one is the emitter. Here is just one of many examples, and I have a bunch of these in my parts box as well.

10PCS 5mm 940nm IR infrared Receiving diode LED Lamp Infrared receiver











5mm IR infrared Launch Emission Tube Diode LED Lamp


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## deedub35 (Jan 29, 2014)

Thanks GRJ for pointing out the incorrectly identified components. It has been a few years since I installed them. On my layout, I have an emitter/receiver pair on each side of the crossing so that whatever the direction the train is travelling it will activate the crossing signals before the train crosses the road.


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## gunrunnerjohn (Nov 10, 2010)

Yep, as long as you have them in pairs, it's not really obvious which way the light is going, after all, it's out of the visible light spectrum. 

If you want to know for sure which one is the IR emitter, just point a digital camera at them, you'll see a dull purple glow from the IR LED.


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## deedub35 (Jan 29, 2014)

Interesting - I will try that.


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## Shdwdrgn (Dec 23, 2014)

This may be of use here... most electronic cameras these days are sensitive to IR. So for example, if you pull up the camera view on a cell phone you can see an IR LED light up. Easiest way to test this is to grab your TV remote and hold down a button. On your phone screen you'll see the LED light up as white.

Once you have a device to see the IR light with, you can use that to check your circuit and make sure it is actually lighting the transmitter.

[EDIT] Erg, and I completely missed that John said pretty much the same thing a few hours ago.


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## gunrunnerjohn (Nov 10, 2010)

Now it's been said twice.


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