Search results

  1. T

    Embedded Systems and Opto electronics

    What ever one your skip, I suggest you take it next semester. OptoElectronics is exciting because of the changes in LED technology that have taken place over the last 5 years.  New colors, Higher outputs, and even Laser outputs. Also the High switching speeds has pushed the network...
  2. T

    Modifying automotive tachometer for fewer cylinders...

    Vi Wh Bl Rd - Gr    7  9  6  2    5% 796 * 100 =79600 Rd Yl Or    - Gld 2  4  3      10% 24 * 1000 =24000 Vi Bl Vi Br - Gr 7  6  7  1    5% 767 * 10                 =7670 Vi Wh Bk Rd - Gr 7  9  0  2    5% 790 * 100 =79000 Those switches can be tricky on the inside.  Some have been...
  3. T

    Modifying automotive tachometer for fewer cylinders...

    Hey , I'm an electronics geek, not a motor head.  Sheshh. Yes I forgot that in ICE's that there needs to be an exhaust cycle for each piston. That would equate to 2 revs for 8 firings in a 8 cylinder engine. That just means we need to divide (or multiply) by 2.  Eh. Not so hard. What is the...
  4. T

    FPGA

    SORRY! See what happens if you don't get your morning caffene! I thought that you were asking about FBGA  (Ball Grid Arrays) (Field Programmable GATE arrays) Ohhhh. well that’s something different. They usually require a (Compiler) that will take a logic formula or some even use graphical...
  5. T

    FPGA

    FPGA means (Flat Pack Grid Array) This is a package type, not a chip type. Programing will depend on what electronics are in the FPGA. Do you have a part number? -Mike
  6. T

    voice activated door opener

    Voice activated without recognizing a voice? Ok, why not. I am going to assume you mean that if you say (OPEN) The door will open for a while and then close again. You might also want to add ‘CLOSE’ later but that is More complex. What you are looking for, I think, is a sound activated...
  7. T

    low rpm dc motor

    That would be called a GEAR MOTOR. It will have a reduction gear on it that produces the slow speed and high torque. Try 'GRAINGER.COM' or http://www.robotmarketplace.com/marketplace_gearmotors.html At least then you will know what you are looking for. -Mike
  8. T

    Modifying automotive tachometer for fewer cylinders...

    Need to know more. What are the values of the resistors you mentioned. What kind of display does it have, sounds like an old moving needle? Can you measure the signal going into the needle display? (is it a DC voltage that varies or maybe PWM signal?) Normally the way a tac works is it...
  9. T

    Irda Help

    I don't have a schematic but I can give you a hint. The modules usually transmit a 38-40khz signal. the transmitter is just an IR led and the receiver is a IR sensitive Photo transistor. An amp and a Phase Locked Loop pick up the signal from the transmitter. The data being sent is transmitted...
  10. T

    Simple timer project - help needed

    You may have broken down your solution the wrong way. Lets look at the rules: 1) Sample the Air only if the fan has been off for 30 seconds or more. 2) When signaled, switch on the fan for 30 seconds than shut it off. It sounds like there is a definite ladder logic to this.  You might want to...
  11. T

    Simple timer project - help needed

    WHile you can get nearly a 50% duty cycle out of a 555 with a little work, it is easier to use a flip-flop to do the work for you. If you want a 30 second on and a 30 second off: Set the 555 timer to pulse once every 30 seconds. it doesn't matter what the duty cycle of the pulse is. Run the...
  12. T

    12v radio transmitter/reciever

    What do you need to know? -Mike
  13. T

    Cold Heat Soldering Tool

    The 'COLD HEAT' soldering iron works on the tiny amount of current needed to heat the element at the end of the device.  Look closely at the end of the tip. It has a divide down the middle.  Both sides of the tip must touch a conductor. The current flowing through the conductor will cause it to...
  14. T

    FETs source voltage

    BJT's are current devices, they use the flow of electronics through the PN junction to create a cascade effect allowing a larger current to flow from Vcc to Vee. Because the flow is proportional, a small current at the Base can control a large current at the collector. (And Emitter if you look...
  15. T

    confused about voltage regulator spec

    Just in case you wondered. The inside of a 7805 looks like this. (Sort of). Depends on the manufacturer. -Mike
  16. T

    12v radio transmitter/reciever

    forgot to attach the picture. ;D _mike
  17. T

    confused about voltage regulator spec

    I've blown them up. :o magic smoke escaped, parts flew, blown up. That protection stuff works for well designed circuits. when you just plain abuse them, they go poof. -Mike
  18. T

    12v radio transmitter/reciever

    That’s a tall order.   How far does this signal need to travel? What you are describing is a CW signal.  A signal that is just a sine wave at a given frequency.  Morse code was sent using this method.  The problem with CW signals is that they are easy to fool and are prone to interference. ...
  19. T

    confused about voltage regulator spec

    close, I think they just put the same part in a cheaper package. there is no differance between a 7805 in a TO-220 case or a TO-92 case. They are the exact same die.  But the smaller TO-92 case will pop like a firecracker if you try to pull 2 amps through it. -Mike
  20. T

    transformers

    Why would you ever want to do that ? Basics?  Well The ratio of turns determines the voltage. 10:1 will convert 10volts to 100v. The number of turns will determine the Power. The more turns the more power. (It has to do with a measure of the coupling between the coils. The whole thing is very...
Top