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#2762 - 01/23/03 10:00 AM Ocelot to Xantech
Dennis Rossi Offline
newbie


Registered: 01/14/03
Posts: 10
I know this has been discussed many times on the message list, but since that's gone, I'd like to (hopefully for the last time) discuss it one last time...

Interfacing an Ocelot (or Leopard) to a Xantech IR distribution system.

Personally, I'm only interested in using the IR-output on my Ocelot to distribute IR out to the rest of my Xantech-wired components. To get IR in to the Ocelot, I simply stick a Xantech emitter over the Ocelot's IR receiver 'eye'. This works great, and from my searches in the past, is the most reliable (and electronically sound) method of getting IR in.

To get IR out, however, I'd rather wire the output jack on the Ocelot directly to a Xantech connecting block. I've actually done this, with some strange results. I wired the signal and ground from the IR-out jack on the Ocelot to the signal and ground on my Xantech 789-44. This works great for the blasters directly connected to the 789-44, but less reliably to other Xantech blocks wired on the same bus in other rooms. I suspect that this is because the relatively weak signal output from the Ocelot cannot make it across the apx 50 to 60 feet of Cat5 (24 gauge) wire without being amplified (the 789-44's are unamplified connecting blocks).

However (and here's what prompted me to post on the forum), while the Ocelot is connected to the Xantech block, other Xantech receivers on the bus in remote rooms (outputting supposedly strong signals) also don't make it the long distance either. When I unplug the Ocelot from the Xantech block, everything works fine again.

I know others have suggested using an opto-isolator between the IR-out of the Ocelot and the IR-in on a Xantech block. What I'd like to understand is why... Does the Ocelot somehow steal the signal going through the Xantech bus? Is that why my other Xantech receivers get affected when it's plugged in? I'm looking to better understand the electronics involved so, if possible, I can build it into the cable I made between the two systems. I'd rather not spend $60 on a Xantech receiver and emitter stuck together if I can accomplish the same thing with a few Radio-shack parts.

Can I get a schematic of the Ocelot, or a least the components of the IR-output jack?

Any help would be appreciated,
Dennis

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#2763 - 01/23/03 02:50 PM Re: Ocelot to Xantech
David Skinner Offline
newbie


Registered: 01/18/03
Posts: 15
Loc: Hensley, AR
I'd suggest the IR-Linc like is used here: http://www.james.lipsit.com/ir.htm
It appears to do opto-isolation and comes with bare wires for the connecting block's screw terminals, but he actually added a stereo plug to make it interchangeable with a Xantech receiver.

Now I haven't used one of these, so I can't make any guaranties.

IR-Linc is an accessory near the bottom of: http://www.smarthome.com/1620.html
cost about $19.95

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#2764 - 01/23/03 03:08 PM Re: Ocelot to Xantech
Guy Lavoie Administrator Offline
Beyond All Hope
*****

Registered: 12/21/02
Posts: 6548
Loc: Montreal, QC, Canada
My "educated guess" about the schematic of the Ocelot's IR output circuitry would be something similar to the collector of a PNP transistor (with it's emitter at +5v) being connected to a resistor of about 100 to 150 ohms and then going to the tip connection of the output jack. The ring of the jack would go to common negative. I'm basing this on when I looked at it with an oscilloscope while it was transmitting to a mini-emitter. You could possibly make an small amplifying circuit like I did to make a blaster but to drive the Xantech block instead. If you know what the expected input of the block is, then this would be quite easy to do.
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"If you don't know what you're doing, do it neatly..."

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#2765 - 01/23/03 04:16 PM Re: Ocelot to Xantech
Dennis Rossi Offline
newbie


Registered: 01/14/03
Posts: 10
[QUOTE]Originally posted by Guy Lavoie:
[qb]...the collector of a PNP transistor (with it's emitter at +5v) being connected to a resistor of about 100 to 150 ohms and then going to the tip connection of the output jack. The ring of the jack would go to common negative.[/qb][/QUOTE]Thanks for the info.

Do you have any theory as to why, when its plugged into my Xantech block, it appears to hinder Xantech receivers in one room from reaching Xantech blasters in another room?

Again, thanks for your insight.

Dennis

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#2766 - 01/23/03 04:52 PM Re: Ocelot to Xantech
Guy Lavoie Administrator Offline
Beyond All Hope
*****

Registered: 12/21/02
Posts: 6548
Loc: Montreal, QC, Canada
Not really, since I don't have any Xantech gear. The only thing I could see is that if the Ocelot's output (when inactive) is somehow "clamping" the input signal line to ground, then it could in fact interfere with other signal sources if their source impedance is high enough. Here is one thing you could try: between the Ocelot's output jack (the "tip") and the Xantech input signal line, put a small switching diode, like a 1N914, with it's anode on the Ocelot side and the cathode (the end with the band) on the Xantech side. This will allow the Xantech end to go high without the possibility of the Ocelot output dragging it down. Let me know if that works.
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"If you don't know what you're doing, do it neatly..."

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#2767 - 01/26/03 06:30 PM Re: Ocelot to Xantech
mjcumming Offline
newbie


Registered: 01/10/03
Posts: 14
Loc: minneapolis, mn
Dennis,

I have been using the IR Link from Smarthome (as suggested above) for almost 1 year. It has worked perfectly and it optically isolates the 2 systems.

Mike

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#2768 - 01/27/03 06:57 AM Re: Ocelot to Xantech
Dennis Rossi Offline
newbie


Registered: 01/14/03
Posts: 10
Guy- The diode did the trick. Connecting the Ocelot to the Xantech block no longer affects any other Xantech receivers or emmiters. Now, I just have to amplify the Ocelot so the signal can reach my remote Xantech blasters...

Mike- Re: I have been using the IR Link from Smarthome...

Thanks. I've heard that it is my best bet. Do you know if it amplifies the signal comming out of the Ocelot?

If it does not amplify the weak Ocelot IR signal, I do not think that it will not be able to control my components (vcr, tivo) that are located further away.

Thanks again to all,
Dennis

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#2769 - 01/27/03 07:14 AM Re: Ocelot to Xantech
John Warner Offline
old hand
*****

Registered: 01/09/03
Posts: 834
Loc: Port Perry, Ontario, Canada
At the risk of tooting Guy's Lavoie's horn - 'cause I know he's so shy , have a look at his clever little IR blaster circuit:

Guy's IR Blaster (Entry 7)

AFAIK, it will work with IR blinkers as well as blasters?

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#2770 - 01/27/03 08:21 AM Re: Ocelot to Xantech
ted Offline
newbie


Registered: 01/13/03
Posts: 24
Loc: Boston, Massachusetts
I've heard in the past that the Xantech IR system is based on 12 V while the Ocelot's is based on 5V. I struggled with this big time last year trying to get my Xantech components to work correctly (Xantech Motorized volume control and Remote Autotransformer) but when I put in the IR Linc between the Ocelot output and the Xantech system everything worked!
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#2771 - 01/27/03 09:35 AM Re: Ocelot to Xantech
Guy Lavoie Administrator Offline
Beyond All Hope
*****

Registered: 12/21/02
Posts: 6548
Loc: Montreal, QC, Canada
Since the diode fixes your isolation problem but you still have a signal strength issue, you could build a small amplifier with two transistors to possibly fix that problem. The IR blaster circuit John refers to is ok to drive an IR LED directly but if you want to drive an IR "bus" system, then you'll need a non-inverting amplifier like this one. The past discussions I've seen about Xantech is that their inputs provide you with 3 terminals: a +12v source, signal input, and signal ground. If that is true, you could try the following circuit (this was just done "by ear", it would need to be tested and some resistor values possibly adjusted):

[CODE]
|------------|----------------o to Xantech +12v
| |
> |
< 1k /
> 1k |v
Ocelot |--mwmw----| 2N3906 (PNP)
IR out / |
(tip) |/ --mwmw---|>|----o to Xantech input
o---mwmw----| 2N3904 | 470 1N914
2.2k |^ (NPN) |
>
| < 1k
| >
| |
o--------------|-----------|----------------o to Xantech common
Ocelot
IR out (ring)


note: the ^ and v designate the transistor's emitters (ascii art!)

[/CODE]
_________________________
"If you don't know what you're doing, do it neatly..."

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#2772 - 01/28/03 04:13 PM Re: Ocelot to Xantech
Dennis Rossi Offline
newbie


Registered: 01/14/03
Posts: 10
Guy - First let me once again thank you for all of your excellent help and advice.

I took the liberty of converting your ASCII-art diagram to a Visio document. If you wouldn't mind, please verify it for me. I got a little confused by your placement of the "V"s on the transistors.



I'm not sure I understand the reason for connecting the +12v from the Xantech to the collector of the NPN transistor. Isn't the base of the PNP transistor a +12v source on it's own? Also, how did you come up with the 470 ohm resistor value to the Xantech input? Xantech places 470 ohm resistors in series with the blaster outputs on many of their connecting blocks. From what I understand, this allows for unused jacks, but it also limits the signal at the blaster, driving it at what they call "low power mode." Don't I want the input to the "bus" to be at "high power mode?"

I'm going to tinker with one of my Xantech IR receivers and my multimeter. I'm sure it's not much more than what you've designed (and they get about $90 each for them!). I'll let you know what I find...

Thanks again,
Dennis

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#2773 - 01/28/03 06:17 PM Re: Ocelot to Xantech
Guy Lavoie Administrator Offline
Beyond All Hope
*****

Registered: 12/21/02
Posts: 6548
Loc: Montreal, QC, Canada
Your diagram is correct.

The reason for connecting the collector of the NPN transistor to the +12v is to allow the PNP transistor to be "off" by having it's base being pulled up to +12 volts when the NPN transistor is also "off". The idea is to re-invert the voltage being amplified by the NPN transistor to begin with, to get a non-inverted output in relation to the input signal. As for the 470 ohm resistor in seris with the output, I just put that there to play it safe with the Xantech input since I don't know how it's made. Like I said, this is a "seat of the pants" design just knocked off on a notepad in 5 minutes and might need a few adjustments to work with your equipment. You can always reduce or even eliminate the 470 ohm resistor if needed. If you try this, let me know if it works, and we could then add it to the list of DIY solutions.
_________________________
"If you don't know what you're doing, do it neatly..."

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#2774 - 02/04/03 08:55 PM Re: Ocelot to Xantech
Dennis Rossi Offline
newbie


Registered: 01/14/03
Posts: 10
...sorry for the delay. I'm back.

I am pleased to announce that the above design WORKS PERFECTLY!

I spent a few days tinkering with my Xantech components, trying to understand the amperages being supplied to the connecting blocks so as to accurately duplicate them with the amplifier circuit designed by Guy. The only component in the schematic that was really of any concern was the 470 ohm resistor between the PNP collector and the Xantech IR input.

As it turns out, 470 Ohms is right on the money, and it results in a high enough signal that is able to travel the full length of the Xantech bus in my installation (apx. 100 ft.).

I have the whole circuit prototyped on a breadboard right now, with aligator clips hanging precariously in my wiring closet. I plan to either wire it up permanently on a general purpose pc-board, or maybe even etch one by hand. Either way, I'll post some pictures in the next few days.

If anyone has any questions about the design or the Xantech components involved, I'll be happy to answer them (I've learned more in the past few days than I ever set out to!).

Dennis

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#2775 - 02/05/03 04:37 AM Re: Ocelot to Xantech
Guy Lavoie Administrator Offline
Beyond All Hope
*****

Registered: 12/21/02
Posts: 6548
Loc: Montreal, QC, Canada
Hey, glad to know it works! I'm also glad my 470 ohm "wild guess" output resistor value turned out to be in the right ballpark. There is one slight mistake that I just corrected in my schematic diagram: I had the transistor part numbers showing as 2N2904 and 2N2906 when they should obviously have been shown as 2N3904 and 2N3906. I just edited my post to fix it and if you could also correct your much better looking visio diagram too, it will make things easier for anyone searching or being pointed to this thread for a solution.

Enjoy!
_________________________
"If you don't know what you're doing, do it neatly..."

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#2776 - 02/05/03 07:00 AM Re: Ocelot to Xantech
Dennis Rossi Offline
newbie


Registered: 01/14/03
Posts: 10
[QUOTE] I had the transistor part numbers showing as 2N2904 and 2N2906 when they should obviously have been shown as 2N3904 and 2N3906.[/QUOTE]...now you tell me!
I figured as much when I went to pick up the parts.

I actually used a 2N4401 in place of the 2N3904 (the NPN) since Radio Shack didn't carry them and, from the specs, it looked pretty close. Also, they sell a 15-pack of general purpose PNP transistors "like the 2N3906" that worked out as well...

I will update the diagram and add Radio Shack part numbers for all components.

Dennis

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#2777 - 01/24/04 07:15 PM Re: Ocelot to Xantech
Anonymous
Unregistered



Dennis asked me to place his image on our server.

The IR AMP image is here:



The URL is

http://www.appdigsupport.com/ADI_Files/iramp.jpg

Dan

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#2778 - 01/24/04 07:30 PM Re: Ocelot to Xantech
Guy Lavoie Administrator Offline
Beyond All Hope
*****

Registered: 12/21/02
Posts: 6548
Loc: Montreal, QC, Canada
Now that's a nice diagram! Sure beats my ASCII "chicken scratches"...
_________________________
"If you don't know what you're doing, do it neatly..."

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#2779 - 02/03/04 08:11 PM Re: Ocelot to Xantech
Todd R. Offline
active contributor


Registered: 05/27/03
Posts: 178
Loc: CA
I built the same circuit, but added screw terminals and a 1/8" mini mono plug cord.

Since my Ocelot is due tomorrow, is there any way to test the circuit before I plug it in

What should my readings be? Is there ever voltage on the Xantech Input terminals? I get 12vdc just left of the diode. Since I used a 12vdc power supply with an LED, I see current flow when I apply 5vdc to Ocelot side, but never anything on the Xantech "in" side.

I assume the Xantech side is 12vdc, Common, and Signal(in) on the IR hub?

Thanks,
_________________________
Todd Reed

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#2780 - 02/04/04 04:15 AM Re: Ocelot to Xantech
Guy Lavoie Administrator Offline
Beyond All Hope
*****

Registered: 12/21/02
Posts: 6548
Loc: Montreal, QC, Canada
With the tip and ring shorted together (on the mini phone plug going to the Ocelot), the output to the left of the diode should show a low voltage, close to 0v. With the tip connected to +5 volts, or even +12 v if more convenient, the same output point should rise to about +12 v.

In other words:

0v in = 0v out
+5v in = +12v out
_________________________
"If you don't know what you're doing, do it neatly..."

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#2781 - 02/05/04 09:03 AM Re: Ocelot to Xantech
Dennis Rossi Offline
newbie


Registered: 01/14/03
Posts: 10
Todd,

In order to test the circuit effectively, you'll need two separate voltage sources- one to simulate the +5v from the Ocelot and another to simulate the +12v from the Xantech.
I believe I tested the circuit using a few batteries and a regular LED.

On the Xantech side, connect a 9 volt battery between the ports '+12v' and 'common'. Then install a regular LED with a 220 ohm resistor in series between the ports labeled 'input' and 'common'. This LED will simulate IR being sent to the Xantech.

On the Ocelot side, use a smaller battery, say a few AAs connected in series. Connect the '-' side to the port labeled 'common' and then touch the '+' side to the port labeled 'tip'. With each touch, the LED on the Xantech side should blink. If it does, you're all set!

Hope this helps.

Dennis

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