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  1. J

    i need help for my a level project

    What are the chess pieces made of? Thinking of another thread just posted, if the pieces where metal you could use a inductive proximity sensor to drive an LED for each square. Not sure what the cost would be though.
  2. J

    Proximity Sensor help

    Well let's see, there are four types of proximity sensors; infrared, acoustic, capacitive, inductive. Inductive is out since nothing you are detecting is metal. Capacitive is also probably out. That leaves infrared and acoustic. The questions becomes if the substances you are trying to detect...
  3. J

    strange questions

    You might think so, but there are a few issues that must be taken care of for it to work properly depending on the requirements of the circuit being activated. That is why we choose not to spell it out. With knowledge comes responsibility. From the look of it, the EP community is a very...
  4. J

    co detector project help needed

    Yes there is, it is called latching. You would need to manually reset a latched circuit. The only issue I see with this is where would the power come from to keep the circuit latched after the CO detector stopped outputting power. Maybe someone else will have a better idea. Up till that part I...
  5. J

    co detector project help needed

    I don't know exactly what kind of CO detector has an output or what power that output produces, but all CO detectors have an alarm and this is an output that could be used to wire up a relay. As for the relay, I would hook it up so that the NC contacts would hook straight into the mains before...
  6. J

    How to make a simple transmitter and reciever? Range > 100 meters.

    so you are comfortable with us telling you how to remote detonate a bomb? What happens if your sons sociopath classmate reads this thread and next week you attend a funeral, still think it is a good idea?
  7. J

    Frequency ?

    Can you explain this a little more clearly, maybe a drawing perhaps? I am talking about doubling the freq with a diode bridge, how does that work exactly?
  8. J

    strange questions

    I know exactly what dave is talking about and after my first post I was eating lunch when it hit me, what that sort of project was all about or could simply be used for. I don't honestly think these people are malicious in their intent, but that doesn't mean that someone else couldn't easily...
  9. J

    How to make a simple transmitter and reciever? Range > 100 meters.

    For the exact reasons you post is also a very good reason why anyone here will not be to willing to help. Ok, so your a cool guy and don't want to blow people up, but there may be others that have malicious intent on their mind and this could be used for evil purposes. Long range transmitter...
  10. J

    SERVIS TFT MONITORA

    it almost seems as if this is a advertisement for TFT monitor repair. I guess we can wait and see what becomes of this.
  11. J

    Help with PCB design... I'm becoming insane! Please help!

    To add to what bob said, you will find all the necessary measurements in the datasheet for the component you are trying to draw. So more or less you need to know all your components prior to making a pcb and you need to stick to them unless you can find a replacement that is a perfect fit.
  12. J

    ****ing speakers, how do they work

    What most people do is try and match speakers to the amplifier. If the amplifier is capable of 200W per channel @ 4 ohm and it has two channel output, then you would by two 4 ohm speakers capable of handling 200W of power. If you try and drive a speaker over its power rating you can blow the...
  13. J

    Mono to stereo

    I am stuck wondering why you need to amplify the signal to the computer from the mic? Plenty of mic's plug into pc's and most do not have a pre-amp, is there some special purpose you are trying to achieve?
  14. J

    How to make a simple transmitter and reciever? Range > 100 meters.

    So what you want is a more like a tv remote, where each button is sending out a different code over the same freq and then each receiver will only activate depending on the code it receives. This would make the freq a non issue. My second issue is with the distance. 100+ meters is a huge...
  15. J

    PV to LED circuit

    Resistors!!! To illuminate a LED you need a power source, LED, and a resistor to control the current. The power source needs to be capable of producing the required power. You do not need a circuit board, soldering or clamping point to point of the components in such a simple circuit is easily...
  16. J

    Tutorials to start with

    Since you are asking how to use a multi-meter, you might just want to start at the beginning of the tutorial section. Each section builds upon the last, so jumping around is only gonna confuse you if you don't have any idea. If I misinterpreted your level of knowledge on the subject I apologize.
  17. J

    How to make a simple transmitter and reciever? Range > 100 meters.

    You are gonna need to divulge a little more info then that if you want help. First question that comes to my mind, will the transmitter be used to send the signal to all the receivers at once or do you need to be more selective? details details details.
  18. J

    Are step down transformers bad for electronics and other transformer questions?

    I don't have any idea, I guess you should ask the people at litefize. But I am gonna assume that a cheaper model will possibly use an autotransformer which we already discussed is a bad idea.
  19. J

    Are step down transformers bad for electronics and other transformer questions?

    http://www.starkelectronic.com/st500.htm "Safety polarized inputs" This is what you are looking for. This model is plug and play. If you want more of a challenge then buy just a regular isolation transformer and wire it up in a box with outlets. Also, I do not see a rock solid power rating for...
  20. J

    Quest smoke alarm randomly chirping

    This is where the smoke enters the device, but what you are looking for is something that should resemble two plate looking things with a space in between. As the smoke fills this void it blocks the signal and sounds the alarm. Get a can of air and blast the whole inside out, exceptionally well...
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