Hi,
I have the power PH508 power horns for my x10 security system. I live in an area that is not near to neighbors. I feel that the PH508 is not loud enough to alert them. I want to use an outside siren that I have and want to use your modification to power the added outside siren. The outside siren is rated for 12volts dc.
What will the dc voltage be at the screw terminals for this modification. Since I have a 12 volt siren, should I assume that you would use a 12 volt relay in this modification.
Will this modification power my siren. Since I do not have any schematics of the circuit it is very hard to understand this modification.
Thanks in advance for the info.
drflash1949Below is your modification that I plan on using.
Q510. How do I add a relay output to the power horn?
The following answer comes from oadebc@robots.gsfc.nasa.gov:
Description:
I have always wanted to add a relay output to the power horn. With this
feature, I can switch on a more powerful outside bell, an autodialer, or
any other load upon detection of a violation. When I opened the case, I was
surprised to learn that unit was already designed to do just that, except
the necessary components have been left out. There even are two holes in
the back of the unit for screw terminals that are covered by a small
sticker. After tracing the circuit, I selected some replacements listed
below.
Procedure:
The procedure requires the installation of eight components that should be
commonly available. Open the case by removing the four screws in the back.
On the PC board you will see near the bottom (side away from the AC plug)
the silk screening for the relay output portion. Install the following
components (all resistors 1/4 watt with exceptions):
R30 - 1Kohm (1/2Watt)
R32 - 12Kohm
R33 - 12Kohm
R34 - 200Kohm
R35 - 200Kohm
D16 - Any Silicon Diode (not Zener)
RL1 - Your relay (see note below)
TR8 - 2N2222 Switching Transistor
For the screw terminals, you can use a set taken from an unused (X-10)
alarm sender, or you can decide on your own interface. The relay could be
tricky. I was lucky and was able to find a relay that fit after some
modifications. It does appear to me however that Radio Shack sells micro
relays that would fit.
Operation:
The relay will close as soon as the horn starts blaring (and vise versa).
Your current rating will certainly depend on the relay you choose. If you
are so inclined, you could even disconnect the piezo horns, and have a unit
that silently turns on a load upon an alarm violation.
Changing the reaction time of the Horn:
After some poking around I found out specifically how the Horn is
triggered. A capacitor is charged a small amount every time an ALL UNITS
OFF command is received after an ALL UNITS ON command. When this voltage
reaches 7.0 Volts, the Horn starts a-blarin'. This usually takes 20
seconds after the alarm system is triggered, an amount that I think is just
too long. The capacitor that determines the reaction time is C13, located
near pin 18 of the 78566 chip. The 'stock' value of this capacitor is
22uF, and it takes five transitions of the command to trigger the horn. By
using a 10uF capacitor this amount is reduced to only two needed
transitions. Summary:
Standard Horn (22uF) trigger time is 20 seconds.
Modified Horn (10uF) 8 seconds.
The quick reaction time will hopefully cause the intruder to stop his break
in attempt sooner.
Effects of Combining the two Mods:
If you want the load that is switched by the relay be flashed on and off,
you can combine the two modifications. The on to off duty cycle can be
changed by changing C13. Actually what I have done is to socket C13, so
that I can open the case and easily change the reaction time of the horn.
Conclusion:
I (oadebc@robots.gsfc.nasa.gov) am curious to know if anyone finds this mod
useful. Please let me know any questions or comments. Have fun, and I
will trust that you will not hold me responsible for your failures (only
for your successes 8-).
Thought I would share some of the changes I've made to my DS7000 Security System, which I've had about 8 years. Maybe someone will have some other ideas I can use.
I live out in the country, about 1/4 mile from my nearest neighbor, so I needed a loud external siren that could stay on longer than the little internal 3 minute piezo speaker. I have the usual DS10A door/window sensors, MS10A motion sensors, a PH508 power horn siren, and a couple other things I'll get to later.
To get an external connection to my system, I added some components missing from the PH508 circuit board that provides external N.O. contacts. Here's a link that explains how to do this:
http://www.baranharper.com/files/x10faq.htm You are probably wondering why X10 left them off and didn't provide external contacts. If I were guessing, I'd say they had trouble getting UL certification with it configured that way and found it easier to just leave the parts out. You should not attempt this modification unless you are qualified. And you should only use the contacts for low voltage. I have noticed some of the X10 modules I have taken apart use what I would call a "hot ground" inside the module. In effect, the AC neutral leg is turned on/off/dimmed, etc. The logic ground for IC packs and other components is connected directly to the AC hot leg. This makes for an extremely dangerous situation if you apply AC power to the module with the case open!
I have the N.O. contacts on my modified PH508 wired to a hidden location that contains a 12V lead acid battery and an Al-6062 timer circuit board. The battery powers an external 120db siren, as well as the timer circuit. When the PH508 triggers, it in turn now triggers the timer circuit which latches on for an adjustable period of time. I have mine set for 60 minutes, although a 20 amp-hour battery could power the external siren for at least 24 hours. The outside siren is going to keep sounding regardless of what happens to my DS7000.
I also have two outbuildings with N.O. magnetic reed swiches wired to X10 PSC01 Power Flash Interfaces. These devices send out a X10 ON or OFF signal to a preset house/unit code on the AC power line. One of my buildings is 500 feet away, so distance isn't much of a factor as long as you don't go through a transformer. I have a X10 appliance module in my hidden location set to the same house/unit code. Then I have a little 12V wall mount power supply plugged into the appliance module. The output of the 12V power supply goes to the trigger input of the same AL-6062 timer circuit board mentioned above. Therefore, my outbuildings trip my outside siren independent of my DS7000 in my house.
I do have a couple issues with my outbuildings. The buildings are not heated, so I have to keep the PSC01's warm in the winter. Otherwise, they seem to fail to trigger somewhere around 15 degrees above zero (Fahrenheit). I have been using a 120V 7 watt bulb plugged into the same outlet and then covering the PSC01 and light bulb with a wooden box. I wish I had a better arrangement. The other thing is I don't have any provision for arming or disarming by remote control, which is also kind of awkward.
Oh, one other thing - don't ever use the little wall mount power supplies with X10 lamp modules. These modules use a triac instead of a relay. The power supply may work for a few months, but apparently the leakage through the triac silently destroys it.