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  1. gorgon

    Help with identifying capacitor

    The markings can be interpreted more than one way, but the value is 100uF. The voltage is a bit more problematic. '1J' on the top may be 63V, and the 25 in the bottom may be 25V. 63V is rather high in a PC, so I think I would vote for 25V, if you don't know there are higher voltages on the...
  2. gorgon

    latching solenoid valve

    The ULN2003 can only drive max 500mA on each output, and the solenoid will take 2A from 12V (6ohm resistance), You should get a more powerfull output device, like a NMOSFET with a logic gate voltage range. You should also do something to protect the MOSFET from the reverse voltage spike from...
  3. gorgon

    latching solenoid valve

    How do you time the pulse? From your drawing I supose you do it by hand, and that may not be good enough. The datasheet define the pulse time to be between 20-100ms, which is hard to do by hand.
  4. gorgon

    latching solenoid valve

    Have you tried to pulse it like it says on the datasheet? I suppose you need to use the 4700 uF to source the pulse current. The coils is 6ohm so you need a fairly large current pulse to magnetice the actuator.
  5. gorgon

    stuck in RPM measurement using pic 18f452

    Or you can use the timer/ counter to count the ticks between the start-to-start flank of one or a number of pulses. Then calculate the elapsd time and divide it on a second. This is faster, and closer to realtime.
  6. gorgon

    Inverse multiplexer

    Or 74hc147, a 10 to 4 outputs priority encoder. Only the most significant input will be decoded at any time.
  7. gorgon

    Split Rail Power Supply

    Everything is possible, but if you want to increase the available voltage, you need to use some form of DC-DC converter. This always comes with a cost, increased power required. In general you may have some problems with an artificial 0v from a single voltage. Due to the requirement of a...
  8. gorgon

    Split Rail Power Supply

    What you are saying is that you want to put in 6V and get +3V, 0V, and -3V. +3 - -3V = 6V. 0V will be the midpoint between +3V and -3V.
  9. gorgon

    Split Rail Power Supply

    Ok, so what you want is a general power that generates an equal negative voltage of the one you put in as positive? I suppose you understand that if you draw a +/- 1A on the outputs, the load on the supply power will be >2A, depending on the efficiency of the inverter.
  10. gorgon

    Mapper

    Why not use a small microcontroller, sending a serial character. like a number <1>. The next send a <2> and so on. on the receiving end you need a microcontroller receiving the number and decoding it on a set of LEDs or a display. You could even have an automatic polarity correction, and...
  11. gorgon

    Interrupt Do's and Don'ts

    Many microcontrollers only save the PC (program counter) when entering the interrupt routine, and the first register you need to save is the flag register, and let it be saved unchanged. Depending on the instruction set you may need to push the accumulator before pushing a copy of the flag...
  12. gorgon

    PIC not working

    If I understand you correct, this would be like lifting yourself by the hair. First you need to take a look at the use of the SPI controller. The SPI clock is used to clock the data into the SPI controller (and out from it), so you'll only see a steady input level from the input, since the...
  13. gorgon

    Interrupt Do's and Don'ts

    I just wonder why you use interrupt in the first place if your program allow this kind of wasted overhead. Relative to the communication time, you waste 50% of your cpu's capacity in this period(one byte interrupted and one byte polled). Depending on the communication speed, thise 'blips' in...
  14. gorgon

    RGB controller

    Just had a closer look at Kevin's schematic. It looks like he has a separate microcontroller to drive the the matrix and one to do the cube manipulations. Ther is a serial connection between them, looks like a standard asynch serial communication. The crystal frequency is 16MHz, so there is...
  15. gorgon

    RGB controller

    Edit: Went to Kevin site and saw a video on how the socalle angle modulation was done. Not musch wiser, but I then saw that there is 16 combinations, or 15 updates on each row. This will change all my calculations, so the ones below is now correct. When each LED has 16 different light...
  16. gorgon

    RGB controller

    Ok, SPI or Serial Peripheral Interface, is a serial interface used to transfer a number of bytes to and from the microcontroller. It is a master/ slave interface, and normally the microcontroller is the master. The master controls the clock line(SCK) clocking the master data output (MOSI) and...
  17. gorgon

    RGB controller

    Give me an example on what you mean by 'terms'. Are you thinking about microprocessor and program things like SPI, interrupt, DMA, background and foreground, or are you thinking about the electronics in the matrix, frames and update frequency?
  18. gorgon

    RGB controller

    Why don't you ask about what you don't understand? I'll be happy to answer direct questions, and I'm sure you do understand some of what is said before. So just ask away. There are no stupid questions, just incompetent answers, at least the first time ;) Don't mind us yapping away, it's...
  19. gorgon

    Figuring the amps on a fuse I need...

    It all depends on what to protect. If the lamp is fused with 6A you should use 4 fuses, one for each lamp, If you combine 2 lamps on a bigger fuse like 12A, If only one lamp is working on this circuit it is not properly protected and could catch fire. For a normal fuse to break you will need...
  20. gorgon

    RGB controller

    The normal SPI controller in microcontrollers are based on a single byte transfer between interrupts. There may be ones with FIFO buffers, but the normal 8bit controller is normally single byte in and out. You can of course poll the controller but this is not the case for that. I've heard of...
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