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  • Users: Chancy99
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  1. Chancy99

    Looking for fine-pitch LED dot-matrix

    Hi All - I'm sure everyone is familiar with the typical 5x7 dotmatrix LED displays. Particularly the ones that snap together so you can build a larger display ... I want something just like that, but with a much smaller pitch or size. All the ones I've seen look like they use the equivalent...
  2. Chancy99

    Need to design AC voltage and current measuring

    Hi Guys - Thanks for all the advice :) I think I'll go with an ADE7753 type for the voltage and current monitoring, using a plain old current transformer. I can get an appropriate one from Digikey for about $11.00. I'll write up the code for doing RMS first, to see if I really need the...
  3. Chancy99

    Need to design AC voltage and current measuring

    ScottyUK - Thanks for the tip - that series looks to be pretty easy to use. Just puts out a DC voltage that correspoonds to the RMS value of the AC being measured. Hmm, doesn't look like it does current measurement though - will still need something for that. I've been looking around at oil...
  4. Chancy99

    Need to design AC voltage and current measuring

    This is a cheap China Diesel, with a 295 engine. Brought in by an importer down in NC. Hardy Diesel sells the same setup, but with better accessories - http://www.chinadiesel.com . Also a lot more $$. I know I can get a simple Murphy switch setup - they have a couple of nice control panels...
  5. Chancy99

    Need to design AC voltage and current measuring

    Heh, yup :) Well, that's what it's capable of putting out. Keep in mind, that's only really about 83A at 120V. Most houses these days are built with at least 200A service, and larger ones with more. The furnace alone pulls 9-10A. Add in the freezer, fridge, computer, a few lights, and it...
  6. Chancy99

    Need to design AC voltage and current measuring

    Hi All - I have a 10kW diesel generator here that feeds into a Xantrex/Trace inverter for power backup at the house. Unfortunately, the generator is fairly simplistic in that it only has a few (lousy) analogue gauges on it, with no protection/detection circuitry at all. I would like to build...
  7. Chancy99

    Voltage divider with diode acting strange ?

    buzzp - When you say the regulator should be able to handle this, we're referring to the clamp diode feeding into Vcc, *after* the regulator, right ? So the regulator should be able to handle having a large voltage on its' output leg. The power input stage is pretty robust. +12V and Chassis...
  8. Chancy99

    Voltage divider with diode acting strange ?

    ...feed into the 12V input, just in front of the regulator. The trouble with that is that an 11V surge will still be fed right into the opamps. That *should* be OK, since their output can only swing to the rails, 0V and 5V. Might burn out the opamp chip package though. If anything, perhaps a...
  9. Chancy99

    Voltage divider with diode acting strange ?

    skogsgurra - Thanks for the words :) I hear you about getting all worked up with protection circuitry there. I'm going to try it with the 6.2V zeners, and if it still has a leakage problem, dump the diodes altogether. My attitude in design here has been to add things in to the layout if...
  10. Chancy99

    Voltage divider with diode acting strange ?

    IRstuff - That's what I'm doing right now with the first board as built. Works fine. Kind of a hassle since all the calculations are off, so the calibration constants in the code are off, so .... Another option is to just do away with the zeners completely. With the 39k, the amount of...
  11. Chancy99

    Voltage divider with diode acting strange ?

    ...TVS clamp, then through a couple of ferrite beads into an AN7705 automotive regulator. The ADC reference uses an LM336-5.0 fed by another 10uH inductor with 0.1uF cap to GND. Clean and quiet. Argh - now I have to desolder the 1N4625 5.1V zeners to put in the 6.2V ones. I *hate*...
  12. Chancy99

    Voltage divider with diode acting strange ?

    ...though, since if there's a load dump, the 12V supply will leap up as well - where would the TVS clamp to ? Given the horror stories you always hear of the automotive environment, I want to make this as bulletproof as possible. peebee - you said to *increase* the size of the resistors ? D.
  13. Chancy99

    Voltage divider with diode acting strange ?

    I'm missing something fundamental here ... I have a typical voltage divider circuit, consisting of two resistors, a 39k and a 22k, plus a 10k pot to adjust things. The 39k is the top leg for input, the 22k and 10k pot are the bottom leg to GND. When adjusted for about 25k, it will divide 12V...
  14. Chancy99

    Headlight wiring voltage drop

    Be careful about high currents though if you go with higher-wattage bulbs. I've seen a 9006 (9004?) high-beam plug half-melt when using 100W high-beam bulbs. Dean.
  15. Chancy99

    Remote starter design

    There are several remote starters on the market at the moment that will handle manual transmissions. The general technique they use is more or less as follows : 1) Put on handbrake 2) Push button x on remote 3) Remove keys (car keeps running) 4) Get out of car, close door 5) Push button y on...
  16. Chancy99

    Remote starter design

    Hi All - I'm thinking about designing and building a remote car starter. I know that there are lots of different ones already out there in the market, but where's the fun and learning in going off-the-shelf ? Most starters use relays, either external triggered from a smaller one inside, or...
  17. Chancy99

    GPIB/HPIB 488 control software

    Just waking this thread up a bit again :) No other ideas for a simple interface to a scope via gpib/488 ? D/
  18. Chancy99

    GPIB/HPIB 488 control software

    ...a mini-Labview. A control panel for the scope would be nice, but basically as you said, just simple screen capture is all I need just now. With *these* components and *this* timing, it looks like *THIS* record-keeping during prototyping and debugging. I like to keep my notes and docs...
  19. Chancy99

    GPIB/HPIB 488 control software

    For example, the 54112D has a hardcopy selection on the utility menu. Of course, selecting that pops up the error msg that there are no HPIB listeners available. So I would need something running on the PC with the NI 488 card that would act as a gateway, receiving the datastream from the...
  20. Chancy99

    GPIB/HPIB 488 control software

    Pete - Yup - the drivers are there. I don't really feel like churning out yet *more* code - I thought that there should be some generic front-ends available. Basic scope, basic signal gen and so on. Ah well, the whip cracks, and I hear it. Back to the keyboard. D/

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