Electronic Challenge Help Requested

(...)

trigger the module thru the "sense" input

Without power to the floodlight, how is it to send anything to the "sense" input?

signal to the module which will turn on

I don't think so. The PIR sensor is blind without power, yes?

trigger the module which presently it does not

Only if the motion detector was powered up beforehand, yes?

looking for a component that would pull

happen.

*Any* coil type relay will probably be low enough resistance to turn that voltage into current. The bad news is that it won't address the challenge.

knew of a component other than a relay they

have a better understanding of what I am

Try it before you purchase a case of them, OK? :)

--Winston

Ok, I forgot to add that the power is connected or applied to both the Module and the Motion Detector at all times except when the switch is in the off position.

All else remain the same as listed.

The lights are connected to the output of the module.

The output of the motion that would normally turn on the lights directly will trigger the module thru the "sense" input wire thus turning on the lights.

The alarm panel will trigger a controller module that will send a Line Carrier signal to the module which will turn on the lights.

I don't need a case of relays, only seven.

Thanks,

Les

(...)

and the Motion Detector at all times

Ah. I see.

Help me here! :)

Are "the lights" something other than the Motion Detector?

trigger the module thru the "sense" input

Do you know what polarity, level, duty cycle, frequency, offset is needed on that "sense" input to get it to trigger? I don't.

signal to the module which will turn on

Except for the bulbs screwed into the Motion Sensor. They come on first, yes?

--Winston

--- Only one: (View with a fixed-pitch font)

ACHOT>---+----------------------+--+ | | | | [R1] | | | | | +------+ +------+ | | +-------+ +--|~ OUT|--|~ COM|--+ +--|~ OUT|--+ | | | NO|--------|SENSE | | +--|~ OUT|--|~ | +--|~ | | | +------+ +------+ | +-------+ | | MOTION RELAY | MODULE [LAMP] | DET | | NEUT>----+-------------------------+-------------+ Select a 120VAC relay with a sensitivity low enough that the leakage current out of the motion detector won't trigger it.

R1 is used to limit the current into the SENSE input of the module and may be omitted if the module has been designed to have mains hot connected directly to the SENSE input.

-- JF

John,

Yes, I got that. The R1 will not be required because the sense is designed to handle the 120vac in.

Still having a problem with a Relay small enough to fit into the limited space. Do know of a different component that can handle the full load other than a relay??

Thanks for the layout drawing.

Les

--
If the module is supplying the load current(20A?)and the relay is only
supplying the current into the SENSE input of the module, then the
relay could be very small.

Do you know what the leakage current out of the motion sensor is?

Hmm.. a Resistor?

I am only guessing on the snubber you may have in that circuit, it could be the generic 100R+.1uf type. or close to that. This would give you a Z = Sqrt(100^+Xc^) = 26539.18

Putting a 10k 2Watt R across the load may bring that down enough to solve your problem.

If you find that 10k does not drop it enough, you'll need lets say around 5k but twice your watts..

All of this is going to generate some heat and heat is a lose of course but only when on. the idle state (off), it'll still be using some power but not much.

Is it possible this unit you have has a lamp burn out detector in it?

P.S. you could also try a .5 to 1 uf AC cap across the output, that may also work. This all depends on the design of the unit.

Jamie

No I did not check that. I only read the voltage at 120vac. My guess is that is would be very small. But it would seem to me that the leakage current would be a minor issue for a component.

Would it not be more important that it could handle full current??

Les

"Jamie" wrote in message news:ojl9r.3021$ snipped-for-privacy@newsfe17.iad...

It is possible but I don't think so since there does not appear there is any type of communcation out of the unit to give that type of indication. I believe that the designer just want to use a "Triac" or something to get away from using a more expensive relay with open contacts.

I like the idea of a resistor but heat generation would be the next issue. So you think that 2 to 4 watts would be enough??

Not sure about a capacitor being the best choice.

Les

--
No, since all the motion detector will be doing is supplying the
current the relay coil needs to energize the contacts.

What we need to know in order to come up with a workable solution for
you is the leakage current out of the motion detector and the minimum
voltage and current required to trigger the module.

Can you post those, please?

(...)

Just hang an A.C. ammeter between the *turned off* output of your security light and ground. Don't allow the PIR module to see anything during this test!

Here is the owner's manual for the module:

--Winston

Sounds potentially dangerous! I'd use a light bulb in series with the ammeter as the test load. ...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.

A resistor. Whether you can find one that's got a low enough resistance to work and will still fit in the box is going to require some experimentation.

If I didn't have a handful of power resistors of the right ratings and values to try, I'd start with a handful of bulbs -- does a 7W bulb hold the output close enough to 0V? A 10W? 25W? etc.

Then, once you've found a bulb to do the job, figure out the current, use that to figure out the resistance and power, and slap it in.

Alternately, observe that a 14400 ohm resistor dissipates 1W at 120V -- so you can get yourself a handful of 1W, 15000 ohm resistors, and start connecting them in.

(Better yet, start with 20k-ohm 1W resistors, or higher -- you really don't want to be running them right up against their power ratings).

If you're lucky, you won't need much.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

I won't be back on site until Tuesday. Will take additional readings at that time.

Thanks.

Les

Now that makes sense to me. I will know more on Tuesday and work it from there.

Thanks,

Les

(...)

Good idea!

--Winston

In my youth I used to trickle charge my car battery using a light bulb and a diode, straight off-line... polarized plug to avoid a "hot" car body. The light bulb served a secondary use... kept the under-hood temperature reasonably warm in Winter ;-)

(When I still lived back East.) ...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.

(...)

Yup. Light bulbs only *appear* simple.

A series light bulb was very useful in tracking down power supply shorts in TVs and radios, I hear tell.

I recall a hobby magazine article about a little plunge EDM 'tap burner' that used a light bulb as a current limiter.

It wasn't terribly efficient. Some miracles are like that. :)

--Winston

One of HP's first products, the audio oscillators, used a "light bulb" in the feed-back loop. I still have a 200AB that works as well as when new. I replaced the line cord, which had given in to Los Angeles smog.

--
Virg Wall