Diode or relay?

Don't know the specification of the X10 inputs but the doc of the burglar alarm should tell it. If you're right, it's the best solution. So try this first. If it does not work, try the schematic below. X10 devices have inputs for hard contacts i.e. relays. Use a fixed width font like Courier to look at the schematics.

R--------+-----+ +-------- | |reed | - _|_ o / 1N4148 ^ |_/_|- / to | |relay / X10 +-----+ o | | ___ |/ +-------- GY--|___|----| 2N3904 2k2 |>

| | B-------------+ created by Andy´s ASCII-Circuit v1.24.140803 Beta

petrus bitbyter

To the X10 input.

+------------+ | | | | | | C 1.5k + ___ B |/ To GY +-----+-|___|-+------+| small NPN transistor |>

• | E | Common of the X10 | +-------------------+ | | + to the (B)

we'll assume (B) is your common (created by AACircuit v1.28.6 beta 04/19/05

Try that.

It's most likely the X10 unit is operating at the 2.5 Volt threshold trigger point. It is common to activate devices using a LOW INPUT (SINK) and there for, many devices have what is called a open colloector output as you see above, to trigger these devices.

The reason you see this activity either way is, you're not getting above the shut off point. You are in the on state level either way.

Jamie

Well, thanks a lot to you (and also to Petrus) for that. It turns out I guessed wrong with diode or relay. That may be because I don't have any hobby experience with transistors.

I'm afraid this is right now over my head, especially since I mentioned earlier that even .2V triggers the X10 burgler alarm adapter. So I don't understand the 2.5 V threshold above. Despite of that, I could easily solder up something for your design if I could just knew the specs of that NPN transistor which I could use to actually pick it up at Frys. The 1.5 K resistor is easy; could probably use the lowest watt rating I can find for it.

Thanks again, Joe

Unfortunately that X10 burgler alarm interface module does not have much of a spec beyond stating that a low voltage *or dry contact* is needed for triggering. A toggle needs to be set for one or the other. (Come to think of it, there might be even a simpler solution for the dry contact trigger, huh?)

Actually, this X10 module is meant to facilitate the conversion of real burglar alarm output to X10 events on the home power network. That X10 event can then be "read" by another X10 module in another part of the home and used to activate some kind of alarm or -- in my case -- turn on an IP camera's recording function to make a video clip. In another thread I already mentioned that this cam's recording function can be triggered by either NO or NC digital input.

Ideally it would be best to just connnect the outside PIR sensor directly to the inside camera (behind the window) without all this intervening X10 stuff, but I don't want to drill through the wall and floor just to run some long wires between them when I can use the existing power wiring for that.

Thanks Petrus, will do.

That goes without saying but I also might want to look into Andy's handy ASCII-Circuit software that you guys have been using here.

2N2222 type or anything in that class.

THe problem is, that X10 works with a sink input. This means it wants to see its own input pulled down below 2.5 volts. In your case, everything you're throwing at it is well below that which means the circuit in your IR unit has a path to the common when not active. WHen the IR unit turns on, it over rides this sink signal and gives you the

• signal you have been seeing.

Just do the simple lay out with the collector directly connected to the X10 input. The Emitter connected to your B line and the base will pass through a 1.5k ohm R which then gets connected to your GY signal.

No matter how you slight it, you need to some how invert the signal if you don't use a relay coil, because the X10 wants to see a LOW state for an on condition and your IR sensor is generating a HIGH state for the on condition. Using a NPN will invert this signal and allow the X10 input to float at its own internal pull up to make the off state..

Just go to frys or what ever you call it and get a 2N2222, 2N3904, 2N4401 something close to it.

I would love to look at Frys for you how ever, it seems that i've never been able to connect to their site. the DNS finds the address but always times out with no response...

Jamie

OK, I I've got it now, thank you. I happened to also check Radio Shack for the transistors, and they've got both 2N3904 and 2N4401, but not the

2N2222.

Does that make a difference that they call the first one Small Signal Transistor and the other one Switching Transistor? BTW, what Watt ratung do you recommend for the resistor?

Hm, I don't recall such a problem for myself.

Thanks again, Joe

The NTE47 transistor available for 69 cents at Frys will work for you. FRYS.com #1798418

Ed

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Good start. Now add isolation with an optoisolator/optocoupler. Use a rather higher base resistor say 10k.

?-)

Thanks, Ed. BTW, how do I know which wire is for Base, Emitter and Collector? What marking scheme is used to indicate that?

Google would find for you... :-?

--
John G

Oops! I didn't think I could find such detailed data sheets for items costing only a few cents. I guess I know now better. Thanks.

All I entered in google search was NTE47 If in doubt TRY IT. I often help people with computer problems, (have been doing it for 40 years, yes long before PCs) and if I don't know immediatly I will be keying someting into search to see what I get. :'(

--
John G

I guess I just assumed that there was some standardized method of marking the 3 transistor leads which is well known by electronics "insiders" and didn't think to search for it on Google. Turns out almost all manufacturers have their own methods for it. Otherwise I also tend to google for practically everything.

Unfortunately everyone has their own standard...

...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.

Yeap. I figured that if they could standardize the resistor values with those color stripes, they probably had a standard for transistor leads, too. How little did I know ...

BTW, that link you provided is pretty good. Thanks, Joe

You are quite welcome! Enjoy! ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.

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That's not a hard and fast rule as there are so many variations of low-volt= age/dry contact interface types out there. If he only has the one toggle sw= itch select for LV or dry contact closure, chances are the input is trigger= ed with a HIGH voltage in LV mode, and by a closed contact in relay input m= ode (LOW). And that high LV could be something like 10V or more. If the uni= t supplies an output DC voltage for its sensors (usually 24VDC), chances ar= e this is what you want to use for pullup source. Some take an AC or DC inp= ut, it is obviously being internally rectified. To make a long story short,= your input polarity is probably going to trigger the unit on when the PIR = is inactive, assuming there is internal pullup.

Petrus, just in case, I decided to get the parts for both solutions when I go to Fry's, probably this weekend. If I guess right, the 2k2 resistor is really 2.2K ohms, but I have no idea what specs or part number should I look for the in the reed relay. Can you name one like you did for the transistor and diode? Thanks.

As for the resistor a 2k2/0.25W (2.2 kiloOhm indeed) will do. Diode 1N4148 or any other general purpose Si diode. Same for the transistor 2N3904 or any other general purpose NPN transistor. The relay may be more dificult. I'd use a 5V DIL reed relay like a MEDER DIP05-1A72-13L or one of the its other 5V family members, COMUS has similar relays available from Conrad

COTO TECHNOLOGY (Farnell

1081659 ) and doubtless several others. FAIK FRYS offers only one 5/6V relais #6401152 manufactured by NTE and one 3V relay #6007528 by PHILMORE. The latter is meant to switch 10A and requires 120mA to switch so it is rather useless for your application. So if you're limmited to FRYS you're stuck at that #6401152.

petrus bitbyter