Search results

Search Forums New Posts
  1. AnalogKid

    how can I create a positive logic pulse from a steady high input?

    Quite a few drummers have taken "inspiration" from NP over the years. I work his fills into all kinds of things. OTOH, some of his work just stands alone. When people asked him which was the hardest song to drum to (next to his solo), for many years his answer was Tom Sawyer. I agree that it...
  2. AnalogKid

    how can I create a positive logic pulse from a steady high input?

    It is a NAND FF, so set and reset are negative true inputs. If any of the three alarm inputs are high, pin 13 is high and the FF is ready to accept a negative pulse on pin 1 (positive pulse out of C1/R5). With the pin 13 node high and current limited by the input pullup resistors, the reset...
  3. AnalogKid

    how can I create a positive logic pulse from a steady high input?

    The posted image is a GIF, which any graphics program can handle. GIF files do not show compression artifacts the way JPGs do, especially with fine line drawings. If you are committed to using the external switch to ground to complete the input LED indications, there is a circuit trick that...
  4. AnalogKid

    how can I create a positive logic pulse from a steady high input?

    OK, this probably is more like what you envision your circuit to be. It does not have the logical tightness of the previous post, but it covers the basics. Note that there are two output stages. Either connect the high side of the alarms to the 555 and the low side to GND, or the low side to...
  5. AnalogKid

    how can I create a positive logic pulse from a steady high input?

    Yeah, I thought it might scare you. Don't panic, that was just me fooling around. BTW on your diagrams are two grey boxes, Trigger and Silence. Are these the pulse forming circuits or something else? ak
  6. AnalogKid

    how can I create a positive logic pulse from a steady high input?

    First pass at the alarm circuit. Remember when I said the circuit could be designed with just about anything? This is what happens when I'm bored at work. All active components are sections of two ULN2004 darlington transistor arrays. I've used it as a logic device many times in industrial...
  7. AnalogKid

    how can I create a positive logic pulse from a steady high input?

    Ran into a small logic issue. What happens if an alarm happens, you hit the silence button, then another alarm happens before the first alarm input line returns to the safe state? My guess is that you want the alarm to go off again. This changes the set circuits. More later. Also, in post...
  8. AnalogKid

    how can I create a positive logic pulse from a steady high input?

    Almost done. The system is reduced to one magic IC plus a 555. Zero logic gates, as in no CMOS, TTL, ECL, DTL, RTL, BTL, CPLD, FPGA, PIC, etc. AND, it will run on anything from 5 to 48 V by changing the LED resistors, and can withstand 50 V input transients without protection. ak
  9. AnalogKid

    how can I create a positive logic pulse from a steady high input?

    And an amateur drummer, a great combination. ak
  10. AnalogKid

    how can I create a positive logic pulse from a steady high input?

    Your latest description wiped out about half of my prelim schematic. So now there is only one latch, and it is used to silence the alarm if the fault does not clear itself before someone gets to the alarm controller. Then, a "shut up" button resets the latch. At this point if an input signal...
  11. AnalogKid

    how can I create a positive logic pulse from a steady high input?

    Two alarm logic questions: 1. If a supply line goes down and trips the alarm, then goes back up before the alarm is acknowledged, do you want the alarm to continue until it is reset, clear itself automatically, or silence itself but keep a visual indication that something happened, like the...
  12. AnalogKid

    how can I create a positive logic pulse from a steady high input?

    The alarm system you describe is not very complex in its logic requirements, and can be done easily with CMOS logic, or LM339 comparators, or opamps, or plain old transistors. And, of course, a PIC, Arduino, or whatever. But all that typing... ak
  13. AnalogKid

    RGB LED controller current extension

    Nice part. There still is the issues of 24 A currents running around. If the three FET sources go through pc board traces to an external connector pin, you might want to add some #16 solid wire in parallel to the traces for lower resistance. ak
  14. AnalogKid

    Modifying pre made delay timer module

    User manual for the timer module? You description is almost clear, and is missing a few details about what the adjustments and switches on the module do. Depending on the details, tt might be possible to do what you want with just adjustments. Is this what you want: Power off - motor off...
  15. AnalogKid

    Field Charging Box - voltage/component question

    IF the switches are on the power supply outputs, they need to handle only the current drawn by the loads, not the entire capacity of the supply. Still, medium current switches with true DC ratings are surprisingly rare. But if these are AC powered supplies, put normal AC power switches on the...
  16. AnalogKid

    RGB LED controller current extension

    That's the basic idea (no warranties expressed or implied). I'm assuming that the controller can dim the LEDs, and uses PWM to do it. If so, then the new FETs have to be fast enough to keep up. Might be a problem because a large MOSFET has a large gate capacitance, and needs a gate drive...
  17. AnalogKid

    Help With Kids Homework

    It's in post #3, but in terms that the OP probably didn't get. I'll translate: Open the switch. ak
  18. AnalogKid

    Help With Kids Homework

    Not sure about the protocol on this forum. I realize that we're not here just to throw out the answer; the questioner has to work for it. But dad "has no idea", junior is asking dad so he's out, and there have been 19 responses. Is it ok to answer the question? ak
  19. AnalogKid

    Help With Kids Homework

    a.i.r c.o.r.e t.r.a.n.s.f.o.r.m.e.r
  20. AnalogKid

    RGB LED controller current extension

    Given that the board has dual footprints, one option is to remove the standard FETs and drop in big fat boys. The problem is the 24 A of ground current. ak
View older results
Top