Jump to content
Electronics-Lab.com Community


  • Content Count

  • Joined

  • Last visited


About Theatronics

  • Rank
    Advanced Member
  • Birthday 09/05/1966
  1. I was taught the basics by my father, When I was young (8 or 9) he had a Ham Radio rig. I started with Tubes and my first active device project was a triode AM radio. It was basicly a crystal radio with a triode acting as a amplifer to drive a speaker. As I remember, it was not all that loud but it glowed and made noise, how much more could a kid ask for? -Mike
  2. Indulis, You are correct, the fixed frequency method works because of the inductance, or more correctly, the impedance, of the whole motor. At a low frequency, Lets say 0hz – DC, the motor sees the full power as current through the windings and thus produces a magnetic field resulting in motion. As the frequency rises the coils begin to interact with the power in the current and some of that current is blocked resulting is losses through heating. As the frequency changes there are nodes (harmonics) that will produce better or worse power but they are not wide enough to use for accurate co
  3. Tkjaz, Looks to be about $3.00 us. Digikey Link: http://dkc3.digikey.com/PDF/T063/1898.pdf Might be able to find them cheaper from other sources. -Mike
  4. Check out a product called Q-Prox http://www.qprox.com/products/touch.php Sensors can pick up finger touches through thick plexy. Edge light your plexy and etch symbols into it for a amazing display/ control panel! -Mike
  5. it's just a speaker. Usually 8 Ohms and less than a watt. here is a typical one : http://www.mycableshop.com/sku/PCCASESPEAKER.htm If you want to mount it outside just extend the red and black wires outside the case. But speakers sound louder if they are mounted in a box so you might want to put the speaker in a box. For all that trouble why not look into a nice cheap sound card? Much better sound quality and much easier to connect to external speakers. Here is a link that shows how to use a real sound card with QBasic. http://www.phys.uu.nl/~bergmann/soundblaster.html -Mike
  6. If you want a "Way Cool" challenge. Connect a row of SMT leds on a stick and spin it. Then using accurate timing, draw the next number in mid air. (Put one digit on the left of center and the other on right of center) Hows that for wizzy bang ? -Mike
  7. It's inside. Open up the box, you will see it. From Q-basic, I don't think so. The external speakers are usually run off a sound card, the internal speaker was rarely connected to an external jack. You can do that if you wish, just don't use amplified speakers unless you knock the voltage on the output down some (See Voltage Divider Resistors for more info) Also, don't connect a speaker larger than the one in the box as you can blow the little amp that drives it and that could be bad also. -Mike
  8. how big of a TFT display? Are you talking about a little 2 line by 16 char type of a larger Computer flat screen type? And how large is the 7 Segment display? I guess it comes down to what you are trying to prove. If you want to show that you can build the circuit then skip the TFT and just use the 7 Segment displays. For larger displays look into “Flip-Dot” displays. They don’t need as much power as large LED signs. If you want to show off and display the output on video then you are talking about something entirely different, the whole counter BCD circuit is insignificant to the video i
  9. OH! I think I get it. He wants to put the scope into the X-Y mode (Ch1 on X ch2 onY) and use the PIC to control the signals to DRAW a game on the screen. If it's a 30Mhz it must be a fair machine so I am guessing it also has a Z input on the back that can be used to control the intensity of the beam. I have seen people build driver circuits and display NTSC signals on a scope screen before. It wasn't easy but they were trying to comply with a broadcast signal. This may be easier because he can control the whole thing. Humm. I’d suggest ‘Vector’ graphics rather than trying to scan the whole
  10. The 556 chip is very similar to a pair of 555 timers. On the left side of the chip the Cap and resistors are used to set a frequency for the signal. Usually this frequency is not needed to be exact. Most servos are forgiving but it should be around three thousand pulses per a second or 3 Khz. Use the adjustable resistor to move up and down the range until your servo starts to respond. The Cap and resistors on the right ser the Pulse width. While the left side of the 556 is acting like a simple pulse generator, this side is wired as a “One-shot” with every pulse that the left side creates ,
  11. Try using a (MosFet N-Channel Enhancement mode) to actually switch the LEDs on and off. Many fets can be connected directly to a microcontroller. (NOT all, check your datasheet) For 50 of them, There may be a PIC that has 44 I/O pins but I'd suggest a different method. Look into "Serial In / Parallel Out" Shift Registers. You can string them together end to end. There is a Serial in pin and a serial Out pin and then (usually) 4 or 8 output pins. There is also a /Latch/ or /Load/ pin. Then by placing the on and off signals on a data line and pulsing a second line to provide a clock signal,
  12. Zoinks, that’s a lot of questions. All right 1 at a time: Touch sensors. A FET touch sensor is the same thing used on those lamps that you touch to change the brightness. IT can be done with any high gain amp. If you have ever touched the input to an audio system and heard that loud hum noise, you know how it works. The input is sensitive and can pick up the touch of a person. But rather than drive an audio signal it just flips a relay. Another touch type switch is called the Q-Prox. It is a single chip solution that uses a simple wire coil to detect a touch. I have included a lin
  13. Paul_J, That’s like the test I was talking about. We did it (2 decades ago) in a class on microprocessors of all things! It was just a side note where the instructor demonstrated how heat sinks have different abilities. He used the Soldering iron as a fixed and constant heat source. But he just glossed over the calculations he used. I do remember now that the goal was to get the whole heat sink to the same temp. A better heat sink Would maintain a lower temp than a poor one given the same energy input. Indilus, Huh? I thought copper was about 2 times better than aluminum so for th
  14. What type of metal is important. (Al is most common) Also the shape is important to some degree. If the part is mounted at one end of a long sink the wattage will be lower than if the part were mounted in the middle of the same sink. I don't know of any actual 'formula' to convert the shape, material, and surface area of a sink into an actual wattage or Efficiency % value.
  15. When you say Miniature, I assume that you mean smaller than human sized? If that is true, the sensors depend on what you expect to ‘trigger’ the doors to open. The classics are: Photo transistor: When exposed to light it will conduct. By covering it (making it dark) it will conduct much less. Cds Cell: Similar behavior, Acts like a resistor that is sensitive to light. Hall effect sensors. If the item being sensed is metal (Fe) based. Fet-Touch sensors: Very high gain sensors that detect the static discharge of human touch. Capacitive sensors: Good for sensing just about
  • Create New...