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  1. audioguru2

    Automated lighting system

    Hi Paul, Now all you need is a pressure/motion switch and an IR remote control system. There isn't much of a circuit diagram for a simple switch. If you want to build your own IR remote control system then it is an entire project by itself. There are many circuits on the web. Go to...
  2. audioguru2

    Audio to DC Motor Driver

    Hi Indulis, The signals that are rectified to activate the motor in the jaw are probably speech. Half-wave rectified or full-wave rectified speech would both be similar, except full-wave would have less vibration and give full output volage. I have my new Sound Level Indicator project...
  3. audioguru2

    Mixer

    There are many different kinds of oscillators to choose from. A 555 IC is usually used. I can't recommend an AM modulator circuit since I hate the poor sound quality of AM. I would use FM like most IR communicators.
  4. audioguru2

    Audio to DC Motor Driver

    Hi Indulis, The main complaint was that the motor was vibrating like a speaker. The full-wave rectifier and filter capacitor takes care of it. I mentioned that if the capacitor's value is too big then the return motion would be slowed. ;D
  5. audioguru2

    Mixer

    An AM modulator simply varies the level of the carrier. Since your IR doesn't care about harmonics, varying the supply voltage of a  transistor in the IR oscillator with the audio signal would give AM modulation. Compact fluorescent lights also produce AM modulated 40kHz IR. Your receiver will...
  6. audioguru2

    Mixer

    If the carrier is already modulated, a frequency multiplier or mixer circuit will increase or decrease the carrier frequency, not its modulating audio frequency. A frequency multiplier, RF mixer or modulator isn't a summing amplifier. I think you want to use the audio to modulate the carrier...
  7. audioguru2

    led problem

    Simply a single-pole switch and a resistor. That's what I did in my new Sound Level Indicator project when I discovered that a pot wouldn't fit: http://www.electronics-lab.com/projects/motor_light/009/index.html
  8. audioguru2

    subwoofer box make

    Hi Omer, There are plenty of internet sites that explain how to calculate the dimensions for a subwoofer box, if you know the detailed spec's for your subwoofer speaker. They even show how you can measure the speaker's spec's yourself. Frequently the speaker manufacturer's website has plans of...
  9. audioguru2

    capcitive touch sensor

    D2 and D3 don't do anything. The circuit will work without them. D1 arrests the few hundred volts flyback voltage spike that occurs when the current in the relay coil is stopped. Q3 would be destroyed without it.
  10. audioguru2

    Audio to DC Motor Driver

  11. audioguru2

    led problem

    Hi Chris, When the pot is turned almost to max brightness, a tiny portion of its resistance will be very hot. It is too small to dissipate the heat and will fail. A physically larger pot would last longer but is very expensive and hard to find. I would use a transistor to dissipate the heat and...
  12. audioguru2

    Audio to DC Motor Driver

    I wouldn't use a puny 1.4A rectifier with a 3A motor. Try a 220uF or 470uF capacitor between the rectifier and 100 ohm resistor. The larger value reduces hum more but causes the jaw to slowly return to home. The positive wire of the capacitor and rectifier connects to the positive supply.
  13. audioguru2

    led problem

    Hi Chris, This circuit will work. The pot might not last long.
  14. audioguru2

    Audio to DC Motor Driver

    Yes. Your motor draws more current. No. Replacing the transistors with more powerful transistors increases their current to match your motor. The voltage of the signal from a little computer speaker's amplifier is too low for this circuit. This circuit should have its own amplifier and volume...
  15. audioguru2

    Help: Determining What Resistor to Use

    A resistor reduces a voltage by dividing the voltage with another resistor. Reducing voltage with resistors causes them to heat. The heat is waste. If the current is high then since you want to reduce the voltage a lot, the resistors will become extremely hot. It might be best to make a power...
  16. audioguru2

    Audio to DC Motor Driver

    Hi Corey, Welcome to our forum. ;D A TIP31 transistor has a wide range of spec's. Weak ones can't drive a 3A motor. Also the MPS2907 transistor isn't strong enough to feed a more powerful output transistor. The output from a computer speaker's amplifier is too weak to feed the circuit. The...
  17. audioguru2

    Gmrs radio please help

    Hi Johnson, GMRS is a high-power portable walkie-talkie system used by anyone with a GMRS transceiver. There are no stations, just users. Maybe many people speak "Mexican" in your area. Maybe you have a different kind of radio. ???
  18. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Tedy, Maybe the spark was caused by a poor solder joint or fused pcb trace to C1. It has a huge surge of current to charge it. Doesn't your project use two 2N3055 transistors with emitter resistors as Q4? Turn off the project quickly if U2 gets hot. Q1 might be turned on all the time...
  19. audioguru2

    Transistor Tester

    The project has an error and won't work unless the error is corrected, as explained in the project's link to its discussion in the forum. The corrected schematic is here:
  20. audioguru2

    Speaker - frequency and impedance

    The cone of a speaker mechanically resonates at a low frequency. The resonant frequency of a tweeter is much higher. The resonant frequency is increased by a small size of the enclosure for the speaker, where air in the enclosure is an additional spring. If the enclosure size is correct for the...
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