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  1. Hero999

    how do I detect red light from LCD screen.

    A red filter doesn't turn light into red light, it blocks all other wavelengths apart from red.
  2. Hero999

    Fm transmitter about

    Why bump such an old thread with no useful comment? If this thread doesn't go anywhere in a couple of days I'll delete it.
  3. Hero999

    The flashing Heart(i have some doughts)

    Which project are you talking about? There are 100s of projects on this site, please post a link to the one you want to discuss.
  4. Hero999

    how do I detect red light from LCD screen.

    A photodiode/transistor with a red filter?
  5. Hero999

    2 ch rf remote

    Lol, I've never heard of a radio controlled egg. ;D Remote controlled toys normally use 27MHz or 433MHz because they don't require a licence. I doubt they use anything as complex as rolling code like a keyless car, it's probably much simpler.
  6. Hero999

    Led voltage and current question

    You shouldn't need a protection circuit. Just ensure the adaptor can provide enough current and its voltage rating is high enough to power all the LEDs. You still haven't said what their voltage drop is. If you don't know, it can be guessed from the colour: infrared are below 1.2V to 1.6V...
  7. Hero999

    Line-input splitter w/isolation transformers

    Audio isolation transformers are used to prevent ground loops. I don't know whether that will be a problem here because you haven't provided enough information about the equipment. Are all the appliances double insulated? Do they have two core or three core mains cable?
  8. Hero999

    battery monitoring circuit

    What comparator ICs are you using? With the circuit as you've drawn it, you need a device which can source current, most comparator ICs such as the LM339 have open collector outputs which can only sink current.
  9. Hero999

    Line-input splitter w/isolation transformers

    It also sounds like you're trying to use an RF transformer. I don't see any need for an isolation transformer, just connect the chassis together and the inputs to the outputs.
  10. Hero999

    battery monitoring circuit

    The comparator will turn on when the voltage at the + input exceeds 5V. You need to rearrange the potential divider formula. http://en.wikipedia.org/wiki/Potential_divider It can be a bit of a fiddle to calculate resistor values that are standard values. It's also a good idea to add a high...
  11. Hero999

    4W FM transmitter

    How did you know that? Assuming what you've said is true, it's only part of the kit and is incomplete. The real kit probably has a couple of RF stages after the part shown here and possible pre-emphasis.
  12. Hero999

    4W FM transmitter

    It's total nonsense. It's probably been translated into English from another language using software rather than human brain. A radio frequency choke is normally just an inductor with a high impedance at the freqency of interest, try a 4.7
  13. Hero999

    Time Delay Relay & II

    Please post links iwhen asking questions in future, didn't you read the sticky? I assume you're talking about the projects linked below: 1) http://www.electronics-lab.com/projects/misc/014/index.html 2) http://www.electronics-lab.com/projects/misc/015/index.html Number 2 won't work because a...
  14. Hero999

    Led voltage and current question

    Please post the schematic. If you want to connect 1000 LEDs drawing 30mA each in parallel you need a 30A power supply. What's the forward voltage of the LEDs? Connecting them in parallel is wasteful, you should connect as many in series as possible, for example if they're red LEDs and have a...
  15. Hero999

    Anyone here na gumamit na ng RGB LED/White LED for color detection

    What problem would that be? The only problem I'm aware of is the spectral response of the detector and I've already said how to fix it. From a functional point of view it doesn't matter whether you use three detectors and one LED or three LEDs and one detector, both are equal. My colour...
  16. Hero999

    Brightest LEDs on the planet?

    The unregulated circuit in my previous post is based on the same topology as the circuits in the post before it. The two regulated circuits I posted both work on the same principle: the output transistor turns on, as the current in the coil builds the voltage across the sense resistor exceeds a...
  17. Hero999

    Brightest LEDs on the planet?

    You're half way there. You need an inductor, not a capacitor if you're going to do that. The value will depend on the switching frequency, input voltage, LED voltage, current and maximum acceptable current ripple. It's true that the current will vary depending on the input voltage but that...
  18. Hero999

    Limiting Mains current.

    Then an isolation transformer is not necessary as long as all parts have class 2 insulation from the user i.e. there's no chance of the insulation failing resulting in an electrocution. See the Wikipedia article: http://en.wikipedia.org/wiki/Double_insulation Yes, if an isolation transformer is...
  19. Hero999

    Laser Sensor and Counter

    It was along time ago, about 15 years. I think that was also wrong, the big bit was positive and the small bit negative.
  20. Hero999

    Laser Sensor and Counter

    I bought some over priced LEDs from Tandy (the now defunct UK branch of RadioShack) which were backwards: the long lead was the cathode and the short lead the anode which could explain this. Here's my suggestion. I'm going to assume that you've already connected the LED the right way round...
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