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Everything posted by Robertc65

  1. Thank you for the reply. If it will help I will make a circuit board for this project. Can you explain the ground plane in a little more detail? I don't really understand it. I can't leave one side of the board unetched can I? My traces will be on the bottom. I don't need any traces on top. What does the ground plane consist of? The more I type the more questions I have. Thanks Rob
  2. Hello. I am wanting to build a video distribution amplifier so that I can send the composite video signal from a single Camera to multiple TVs or devices. Radio shack has their video amplifier for $50 bucks or so but I need one for each of my 8 cameras and that will get to expensive. I discovered the Maxim MAX4136 IC which is just what I am looking for. It's an IC with 1 video input and 4 outputs. It looks to require just a few discrete components. The application notes detail how best to design the circuit board to keep noise to a minimum. My question is, do I really need to use a circuit board? The IC is surface mount if that matters. There are not really that many connections and a circuit board just seems to be a waste of time for my DIY project. I plan to mount it inside of a metal project box and run wires directly from the IC leads to each RCA video output jack. The wires should be no longer than 1.5 inches. Has anyone ever had any experience doing this sort of thing. Am I just creating a video noise box here or what?
  3. Thanks for the info Ashtead. I like the idea of the opto-coupler. I now need to figure out how to build the actual relay driver circuit that will be switched on by the Transistor side of the opto-coupler. Do you know if there is a good example of a relay driver circuit like this somewhere? Thanks Again Rob
  4. What is an LDR? I have never heard the term. I'm guessing "Load ? Resistor" Not sure. I don't have a schematic unfortunatly. In most cases I don't think I could do with out the LED. As far as looking at what drives the LED and trying to determine how much current is available I was hoping to have a more generic approach. My thinking may be flawed and correct me if I'm wrong, but don't just about all LEDs that would be used for say an indicator light drop 1.5 volts and draw less than say 20ma. The 1.5 volts is pretty much a given and the current unless it's some sort of specialized LED should be pretty much within a given range also. Given these specs and assuming that we can remove the LED is there a simple circuit that would work most of the time without having to be concerned about specifics of what is driving the LED. Thanks again for the help. Mt theory may be all wrong here. I'm just thinking out loud. Rob
  5. I am always looking to automate things in my house and often times it would be helpful to be able to control a relay based on the status of an LED. For example I just purchased a wireless driveway automobile monitor and I would like to tie it into my homeautomation system. It has an LED that turns on when someone comes pulls into the driveway. Not just for this project but in general is there a simple circuit I could build that would allow me turn on a relay when an LED lights up. I'm thinking I would need to either turn on a transistor or some sort of gate 1st so as not to load the LED driver circuit. This xsistor or gate IC would then drive another xsistor that could sink enough current to close a relay. Thanks in advance Rob
  6. I have a bunch of X-10 ws467 wall switches laying around that I would like to modify so that they can drive a relay. They are designed to drive a 60 watt incandesent light with the use of a triac. The triac won't drive motors and non incandesent light which is why I want to use a relay. Has anyone ever tried to do this before? I attached the schematic.
  7. Thanks for all of the ideas. That is just what I need. I must be brain dead. I'm was not thinking that an LED is really a diode. I don't have to be concerned about the voltage drop. I have a 6 week old baby at home who has proven to be nocturnal. As a result I have been very sleep deprived lately. Sorry for the confusion. You guys are a great help.
  8. Thanks for the reply. Yea I would like to do it via PC control using a modem. I'm not talented enough write all the code to do this so I guess I'm looking for a program that is already out there. Like I said before Homeseer will do it but at quite a cost. I need to do more searching. I image someone else has already thought of this. The phones you speak just won't give me the ability to change the ring into something I can input into my intercom system.
  9. Is there a way to convert a telephone ring signal into something I can pump into my intercom system AUX line input? I want to turn off all my phone ringers and just have a very pleasant sound come from the intercom speaker in each room when the phone rings. Ultimatly I want it to announce who is calling from a database and not even ring the phone if someone is not in the database or on my reject list. I know you can do this with Homeseer and the optional Homeseer phone. You also need to buy a $100 modem to ensure that it works per Homeseer. Has anyone ever setup a DIY rig like this.
  10. So how much voltage will be going to my LED in this type of circuit while using a bridge. I don't see anything here that limits the voltage down to below 10Volts or so? I quess I just don't understand.
  11. Do the circuits you posted use a typical 1.5 volt LED or are you refering to an LED designed to run at 110 volts? Yes I agree Audioguru I would not be happy if it were blinking so I like the idea of a full wave bridge also. Thanks Rob
  12. Audioguru, No offense intended just trying to be funny. I also used to make pipe bombs and such but you sure can't do that anymore without people over reacting. My electronics experience consists of 13 years repairing consumer electronics equipment which I thankfully quit doing before you could buy a VCR or DVD player from Walmart for $29.95. I gave it up in 1994 and have worked as an Enterprise Computer systems engineer ever since. I do still like to experiment and build electronic gadgets, but I have no real circuit design experience. I just use schematics and such that I find on sites like this and know enough to integrate them and get them working most of the time. Back to trying to light an LED with 110 volts AC. Can I do this with just a resistor or two or is it more involved? Thanks again Rob
  13. tnt2k, Thanks. I did see happen upon this link a while back and it's one of thhe placed I found out about leaky coax in the 1st place. I guess what I should have asked was Has anyone ever built a DIY leaky coax perimeter rig? It sounds pretty high tech using sophisticated signal processing algorithms. Mine doesn't quite need to be built to the same specs as what the Military uses. If mine falses every once in a while no big deal.
  14. I posted a while back asking if anyone had heard of using leaky coax cable and associated circuitry for use as a perimeter sensor. I just wanted to throw it out once more. Thanks Rob
  15. Hey audioguru, Have you never blown anything up just for fun? Are you afraid of a little popping sound or just don't want to blow 20 cents on an LED experiment. You seem a little rigid. Lighten up, The book is not always right. I changed my spec. I have decided to migrate my 6 outdoor light switches into one 6 gang switch box, with single Pole X10 switches. I'm mounting the 6 switches in a hallway equidistant to the front and back doors. This greatly simplifies my indicator issue. Now we are simply dealing with how to light an LED with 110 Volts AC without causing adioguru to get upset at the potential of a popping sound accompanied by a slightly delayed unpleasant smell.
  16. Basically each circuit will power either 2 or 4 150 watt flood light bulbs. I do plan to use an LED as the indicator so the 1.9volts is the maximum voltage drop I'll need across the secondary. I work with computers for a living and have plenty of junk around so I'll scavange a few to see if I can find any coils to use. Thanks for all of the good info. Rob
  17. Thanks for the suggestion. I searched for a 30mm toroidal core and found that I could easily buy them in lots of 1000 or more from any number of questionable offshore manufactures, however I just need a few. I checked allectronics.com and digikey.com. All electronics a a few cool toroidal xformers but no cores. Digikey may have them but they don't show the size. Do you have any idea where I may find one. Thanks Rob
  18. I want to mount an LED or some sort of Lamp on each of my switch plates that control outdoor lights so that I can tell if they are on or not without having to look out the windows. If all of my lights used a single 2way switch this would be easy but all use 3way switches. On te switch which connects to the actual light this is not a problem but what about the other 3way switch that is connected to the power source. It seems that I need some sort of circuit that can sense current draw or voltage drop. has anyone ever done this before? Thanks in advance Rob
  19. Has anyone ever tried to make a DIY Leaky Coaxial Perimeter Detection System. I would like to be able to detect if anyone crossed the perimeter of my property in or out. I have about an acre and figure it's a great way to know if my kids left the yard or someone came in. The systems I found while searching seem to be marketed to the high end. VIPS, Military installations, Water Treatment Plants and such. The systems sound like they are pretty sophisticated in order to to eliminate animals, wind etc from causing false alarms.
  20. Thanks again for the replies. Based on the advise given I'll shelf the voltage divider idea. If I find a schematic for the Compaq supply I'll post it. Thanks Rob
  21. Thanks to the both of you for the detailed response. Doing this on the outside of the supply just doesn't sound like a wise plan. I'll see if I can dig up a schematic. I didn't realize that a switching supply was so sensitive. Taking this Compaq supply put of the mix, would the voltage divider circuit work on the output of a simple non-switching supply using say an LM7812. Could I reduce the 12V output of this circuit to 6V using two of the same vaule resitors (1K or so) in series across the output. I'm just trying to understand because I have three shoe boxes full of assorted non-switching, basically wall wart type supplies I would like to use for various projects. Unfortunatly most of the are 12 Volts and higher.
  22. I understand what you are saying. The switching supply will try to maintain the 18V output depending on the load. What if I were to connect two say 1K resitors in series across the output leads then connect the + side of the camera to the junction of the two resistors and the - side to GND. Would the camera then see 9Volts?
  23. I have a bunch of old Compaq Laptop power supplies that output 18.5V at 2.7 Amps. I would like to be able to use these power supplies to power items that require a lower voltage. For example I have a small camera that requires 12Volts @ 200ma. Is there a simple way to (maybe a resistor across the output of the supply) reduce the output voltage from 18V to 12V. I'm sure in time I will come up with other uses for these power supplies that may require other output voltages say 5V or 3.6V. Thanks in advance
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