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  1. CDRIVE

    Boost solenoid driver circuit

    I didn't know that but the manufacturer spec on this one is 30Hz. I assume that's a max? I'm having a hard time getting my head around a solenoid traversing from fully retracted to fully extended at frequencies in that region. Do these proportional solenoid valves fully open & close or float at...
  2. CDRIVE

    MOTOR SPEED CONTROL

    Do you own a scope? What's the output voltage and current specs of the hall sensor?
  3. CDRIVE

    Boost solenoid driver circuit

    So Kris, when all is said and done do you think that you can make this solenoid operate at 500Hz? I think the electromechanics of a solenoid make it highly unlikely. Chris
  4. CDRIVE

    Boost solenoid driver circuit

    No I haven't. That said, what I do know about the nature of solenoids, I don't think you'll be able to do what you're attempting.
  5. CDRIVE

    Chronograph for bullets

    I don't see the relationship of 1ft panel spacing to muzzle velocity vs down range velocity. The closer you make those panels the greater the demands on the electronics, mechanics and the greater the chance of errors.
  6. CDRIVE

    Logic switching of 205v

    Then we're talking 20mA LEDs. That means the transistor Ice requirements will be low. Just make sure it's saturated well.
  7. CDRIVE

    Logic switching of 205v

    You didn't state if these were high current LEDs or not but here's another HV NPN. http://www.digikey.co.uk/scripts/DkSearch/dksus.dll?WT.z_header=search_go&lang=en&keywords=ZTX458-ND&x=15&y=18
  8. CDRIVE

    Chronograph for bullets

    Maybe I'm misinterpreting this. The panels (1 & 2) aren't spaced 1 Ft apart for a direct conversion of ft/sec? Re Debounce: I think Steve included that merely for reference. As stated, the SRFF doesn't need it.
  9. CDRIVE

    Logic switching of 205v

    I'm sure other members can suggest others but I found these.. http://www.ebay.com/itm/TIP50-HV-NPN-Transistor-400-VCE-1A-TO-220-Lot-10-/220741396856
  10. CDRIVE

    Thats How Computers Are Made

    Dave, that's a hoot! Chris
  11. CDRIVE

    MOTOR SPEED CONTROL

    A Picaxe doesn't require a PIC programmer. http://www.picaxe.com/ Getting started is inexpensive. BTW, since you referred to frequency I'm assuming it's an AC motor but I'm not familiar with induction type motors that run at 5000RPM? Are you sure you're not referring to PWM?
  12. CDRIVE

    Logic switching of 205v

    Use an OptoIsolator. The uC drives the LED section and the NPN PhotoTransistor section drives the base or gate of a HV NPN or FET respectively.
  13. CDRIVE

    Chronograph for bullets

    I would have edited my last post with this question but sometimes the edits get missed . Regarding your counter. Since you don't have a multifunction counter and your going to build it, why not build it as a stop watch to begin with? Chris
  14. CDRIVE

    Chronograph for bullets

    Perhaps it was stated earlier and I missed it but this is the first I'm reading that the target panels are kaput once the bullet has impacted them. I'm exhausted just thinking about trucking back and forth down & up range to replace them. :eek: What happened to the photoelectric panels that...
  15. CDRIVE

    Need advise on controlling the speed of a drill motor.

    What are you going to be using the drill motor for?
  16. CDRIVE

    Personal Locator Beacon

    Actually, I believe an EPIRB operates in reverse of a GPS. A GPS is a receiver not a transmitter. While the EPIRB is a transmitter who's signal is received by satellites.
  17. CDRIVE

    Chronograph for bullets

    There are a number of things wrong with your circuit. (1) If you're using TTL the value of those resistors on the input of the SRFF are waaaay too high. I wouldn't use values that high even if it was CMOS. (2) Detector1 represents the first sensor that the projectile strikes. This gets...
  18. CDRIVE

    Australian - Magnificence!!!

    Sorry about that Dave. These old eyes aren't as sharp as they once were. I looked for a general chat section but somehow missed it. I'll look again more carefully and it won't happen again. Edit: Now I see how I missed it. It's not in the 'Forums' section. ;) Chris
  19. CDRIVE

    What is this box looking thing??

    My vote is on a power supply too. I don't see any reason for heavy duty rectifiers to power heating elements. Was your father in-law a ham or machinist?
  20. CDRIVE

    help with understanding the mysteries of transistors

    Since you're using LT Spice I recommend playing with the 'DC Transfer Characteristics' function. It gives you a very clear picture of base current, voltage vs collector current and voltage.
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