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  1. gorgon

    Crashing after 145 seconds

    Even if you run a compiled BASIC program, you'll necessarily run on top/as part of an inbuilt kernel, almost like an operating system. I did not say that you can't compare it to a compiled C or assembler program, I said a barebone C or assembler program. Where your program has total control...
  2. gorgon

    Crashing after 145 seconds

    The whole idea with the watchdog system is to let it time out if your code is taking a stroll in the park, and you're not aware of it. You'll only reset it at certain points in your program, and never inside interrupt service routines. If you need to take big delays in your code, a more...
  3. gorgon

    My Power Supply Saga

    What's your input voltage with and without load? What's your output voltage with and without load? (over the load) How do you measure the current in the load? Where do the voltage drop? TOK ;)
  4. gorgon

    optical punch card reader

    With a 1 inch wide tape, that's close to 1 time around the Earth at equator. With a reading speed of 110bd, as the KSR-33 had, it's 124 years before you know the last byte. :D A pity I dumped my old 'Olga' the KSR-33 when we moved last time. :( TOK ;)
  5. gorgon

    12V / 6A Power supply. Help with Buck and Boost converters + OR'ing circuit

    From what I have read about Li-ion charging, I think the charger will not function with the load of a boost regulator messing up the charge cycle. The best would be to turn off the boost switcher until the main voltage pass a threshold, and then start the switcher. TOK ;)
  6. gorgon

    optical punch card reader

    Well, going from LDR's to Gb sounds like mocking to me, but never mind. TOK ;)
  7. gorgon

    optical punch card reader

    If you want to use visible light, you should make a baffle in front of the phototransistors, to reduce their 'angle of sight' and to dampen the ambient light. It might in fact be a good idea to use phototransistors with a base, so you can reduce and bias the sensitivity if necessary. If you...
  8. gorgon

    optical punch card reader

    It will be both too sluggish and too big to implement easy. For a swipe reader the electronics and optics must be significant faster than the fastest person using it. If you just want to experiment, it's ok to be inside the user envelope, but only a while. You should use an optotransistor...
  9. gorgon

    2x2x2 LED Cube (Bi-Color, 2Pin)

    I suppose you are right for separate leds. I had the tri-colour configuration in mind and that would be a bit tricky. But, I stand corrected, at least on one leg. :) TOK ;)
  10. gorgon

    2x2x2 LED Cube (Bi-Color, 2Pin)

    Ok, did a little droodling here. You can drive each (dual) LED with 2 transistors only, but it will cost you current. For a 5V circuit you'll need 2.6 x the current trough the LEDs. if you set 20mA LED current, you'll draw around 53mA. You'll also need 2 lines to control the LEDs, one for each...
  11. gorgon

    2x2x2 LED Cube (Bi-Color, 2Pin)

    When you say 2x2x2, are you talking about 4 dual diodes or 8 dual diodes? Some other questions: Do you want to time multiplex these or just showing one at the time? I suppose you want to blank the unused LEDs when not in use? Are you going for a tri-colour solution? TOK ;)
  12. gorgon

    The 555 IC Timer in an LDR curcuit board(Light sensitive trigger)

    What is it you don't understand? This circuit works as a comparator. If the pin 2 get below 1/3Vdd the output(3) goes high, If the pin(2) get above 1/3Vdd, the output(3) goes low. To do this the input pin6 must be higher than 2/3Vdd. On your last (reversed) drawing pin7 is pulling pin(6) low...
  13. gorgon

    Measuring Current

    The bridge recitifer is normally mounted on the rear of the alternator. Regarding the 'peeve' around prefix 'µ'. It's normal to use the letter 'u' to replace the 'µ' character. To my knowledge 'u' has no other use in this field, and historically the letter 'µ' has not been available on most...
  14. gorgon

    Running small relays... Voltage drop.

    Could also be your cable connecting the relay. Is it flimsy? Do the load switched by the relay also load the power? TOK ;)
  15. gorgon

    Digital Pot setup

    In the PIC datasheet you can find here: http://www.picaxe.com/What-is-PICAXE/PICAXE-Chip-Labels TOK ;)
  16. gorgon

    Digital Pot setup

    Have you got a capacitor on the output, and how do you measure the output, DVM or scope? The 20mV could only be induced noise on the measuring leads. TOK ;)
  17. gorgon

    Running small relays... Voltage drop.

    The drop is over the power supply, reducing the output. Have you tried to measure the resistance of the coil? Small cheap 5V relays can easily draw from 40 up to 100mA. TOK ;)
  18. gorgon

    Digital Pot setup

    '0' is the lowest step = 0V. A '1' will give you 0,15V @5V supply. '31' is the max value = 31/32*5V = 4.84V in theory. TOK ;)
  19. gorgon

    Digital Pot setup

    The DAC is a 32 step resistor ladder where each step is approx 5k, rather high impedance. The mid-step will have an impedance of about 40k, gradually lower up and down. TOK ;)
  20. gorgon

    Parallel Circuit - Fireworks Firing System

    I would have used a 5W wirewound power resistor. The few seconds the power is applied will average out, even if it is higher than 5W. TOK ;)
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