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  1. BobK

    A programmable melody generator

    Hi Badi, and welcome to the forum! You could accomplish the same thing with a microcontroller. If you are interested, I could help you out on this forum since I have done similar. Do you have any experience with microcontrollers? Bob
  2. BobK

    random signal generator

    Hi Franz, and welcome to the forum! That is easily doable with a microcontroller, not so much without. What level of experience do have? Bob
  3. BobK

    Constant Power Supply

    A desktop PC power supply will give you 12V and 5V high amps. You could use a boost converter to get the 24V. Oh, and welcome to the forum! Bob
  4. BobK

    Mosfet bridge safety

    All this is great info in general about using MOSFET bridges. But the OP stated that the MOSFET failed and was not even warm. So I think shoot through or overcurrent are probably not the problem. More likely the gate destroyed by a voltage spike. Bob
  5. BobK

    Need help on converting 0-5v signal to 0-10v signal

    I think they can be has as singles as the LM321. Any op amp that can output close to the 0 rail used with a power supply that allows it to output 10V will work. Bob
  6. BobK

    Mosfet bridge safety

    Yes, I should have mentioned speed as well. I am currently using a MOSFET bridge for motor control and I do not have external diodes, but the ones in my MOSFETs are rated at 1.6A and the motor current is 200mA. I do not see any voltage spikes. Bob
  7. BobK

    Need help on converting 0-5v signal to 0-10v signal

    An LM324 would be able to output 0-10V if you have a single supply of 12V. Bob
  8. BobK

    Mosfet bridge safety

    One form of protection is a zener diode from source to gate to prevent too high a voltage on the gate. It should have a breakdown voltage a little above the drive voltage. Also, are the body diodes of you MOSFETs rated to carry the max current you are sending to the motor coils? If not, you...
  9. BobK

    Strange problem help needed!

    I would guess that it is disabling firing for a time after a hit. And the added wires are introducing enough noise to make it think it is seeing hits. An IR sensor would normally have 3 leads. Can you show a picture of the sensor and the circuit board? Bob
  10. BobK

    Drive-in speaker ideas

    Gryd3, Humorous misinterpretation there. When I read your post, I thought you were suggesting stealing something from a phone booth. And where would one find a phone booth these days anyway? Bob
  11. BobK

    Lowest deltaV buck regulator

    Theoretically, a buck regulator should work all the way down to the desired output voltage. In that case the PWM duty cycle becomes 100%. The only loss is the resistance across the switch element, which, with MOSFETs can be very low. I believe I have seen buck regulator chips that claim to...
  12. BobK

    Op amp output into op amp input?

    These are comparators, not op amps. From looking at the data sheet it does not seem that you have done anything wrong. The differential input is allowed to be the full supply voltage. So it should work okay, with the output going high when the + input is higher and low when the - input is...
  13. BobK

    Help making pcb for this camera

    I would attempt to solder that to a PCB as follows: Make the pads about 3/4 the width of the pads on the camera. This is so you don't short together 2 pads, which are very closely spaced on the camera. The pads should extend about 1 mm beyond the end of the camera outline. Fill up all the...
  14. BobK

    circuit design for a game

    Since the ball is not connected to anything, there is no practical way to detect that it has touched a line. If, however, you mad the line out of multiple parallel lines with alternate ones connected together, and the ball touched two adjacent lines, then you could detect that the circuit had...
  15. BobK

    laser ablation of PCB resist

    The traces in the SOIC breakouts are definitely smaller than I can handle with photoresist. I am only really confident in traces and spaces of 0.012, and will use 0.010 in a pinch. I would need a maximum of 0.008 to get a trace between the pads of and SOIC. These look like 0.006, which I...
  16. BobK

    Servo info wanted

    Here is pseudo code to do 2 servos: int servo_1_pulse; // number of microseconds of servo 1 pulse int servo_2_pulse; // number of microseconds of servo 2 pulse int remainder; // number of microseconds left in 2 milliseconds after the last servo pulse goes off while (1) {...
  17. BobK

    Renewable Energy

    Spinning a DC motor will produce a pulsating DC voltage. To get a steady voltage you will need a rectifier and a capacitor. Whether or not you need a steady voltage depends on the load your are powering. For example, if powering an incandescent light bulb, the pulsating voltage would work...
  18. BobK

    Non-changing current with C-EMF

    Yes, that has come up before. People think back EMF is a bad thing. It is not, electric motors would not be practical without it. Bob
  19. BobK

    Controlling LEDs using the serial port

    It means that the output pins can source 20mA when high and sink 20ma when low. If the load you are controlling requires more current than that, you would need a switching transistor or relay in between. If you have an actual DB9 serial port on your computer, there are two control outputs that...
  20. BobK

    Problem faced in generating more i/o's through AVR

    Actually, the easiest way is to get an AVR with more pins, up to a point. Bob
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