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  1. Re: AC constant current LED driver controlled by output pin

    When I mentioned the lower power LEDs I meant those whose If < 25mA. I often use these small red LEDs in the 0805 package on my boards for different purposes. With IOs powered at 3.3V I usually use...
  2. Re: AC constant current LED driver controlled by output pin

    Phil,

    You're right. What I wanted to achieve was to regulate the voltage across the LED which will cause the constant current. For the high power diodes brightness veries with temperature hence...
  3. Re: AC constant current LED driver controlled by output pin

    This is how I would do that

    85601

    You could use this MOSFET - http://www.fairchildsemi.com/ds/RF/RFP12N10L.pdf.
    Any rail-to-rail signle voltage opamp would do. Power it from from the 5V...
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    [in progress] Re: How to build IC tester with board?

    What do you really want to test? Do you want to test the parts functionally (check if they perform the correct logical operations) or test their 'analog' performance (VinH/VinL, VoutH/VoutL,...
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    [in progress] Re: DC Linear Actuator Control

    With a linear actuator you need to add a limit switch or an encoder unless you find one that has one built-in.

    How about a high torque servo? You have all-in-one solution this way. You'd need a...
  6. Re: The Octocopter - MattG, don't let Ken see this video

    With 8 lawnmower size engines the guy doesn't wear the earmuffs? I admire him...
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    OMG! QuadCopter Catches PingPong Balls

    That looks really neat but it makes me wonder if all the misses were just edited out.

    http://www.youtube.com/watch?feature=player_embedded&v=dL_ZFSvLXlU

    Compring to this just building a...
  8. [unsolved] Re: My humid reading is 2330% - HS1101 humidity sensor- please help

    I hope it's not just 23.3%. On the other hand that seems too dry for San Jose...
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    Re: RC plane auto pilot

    I agree with sylvie369. Buy some light plane that can be fixed easily. The chances are during the initial testing you'll crash quite often.

    Also, to tweak your PID loop parameters you may need a...
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    Re: RC plane auto pilot

    An accelerometer may not be enough to keep the RC plane level. You'd need a gyro. The big disadvantage of an accelerometer is its sensitivity to... acceleration. It will gave you a good reading of a...
  11. Re: how to compatable pick bi polar stepper motors and Transistor for the porpeller c

    You won't be able to use the ULN2803 for a bipolar (4 wire) stepper motor because each driver there is an open collector type. For a bipolar stepper you'd need a push-pull driver like this one:...
  12. Re: H bridge driver for 2 Pchan and 2 Nchan mosfets

    Gatcha. If switching the current direction is slow I'd suggest a simple DPDT relay. No need to drive the bridge FETs at all this way.
    If not the Fairchild part seems good but I'd check the FETs'...
  13. Re: H bridge driver for 2 Pchan and 2 Nchan mosfets

    I heard the power lines running but they are 100kV (or more) hence the buzzing if that's what you're talking about.
    Obviously you'll have coupling to your other wires due to the mutual capacitance...
  14. Re: H bridge driver for 2 Pchan and 2 Nchan mosfets

    If it's 15V it may be better to use this IC instead: http://www.fairchildsemi.com/ds/FA/FAN3278.pdf

    Why 10A/15V means no PWM?
  15. Re: H bridge driver for 2 Pchan and 2 Nchan mosfets

    Tommy,

    The optocoupler solution would be ok for very low switching speeds. When you switch the MOSFET gate you're switching a large capacitor. The higher the speed the more power you need. That...
  16. Re: H bridge driver for 2 Pchan and 2 Nchan mosfets

    I agree with Phil. It'd be better to use 2 n-MOSFET's. A pair of NMOS and PMOS are rarely used nowadays because the p-channel is approximately three times weaker that n-channel with the same physical...
  17. Thread: Gps 2850

    by alex123
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    311

    Re: Gps 2850

    One more thing. I just looked at the module schematic. Are you using the SIO pin on the 4 pin header to communicate with the module? According to the schematic the TX and RX lines are located on the...
  18. Thread: Gps 2850

    by alex123
    Replies
    3
    Views
    311

    Re: Gps 2850

    Are you seeing any activity on the Tx pin on the GPS module? Take a look at it on the oscilloscope. If you see nothing it's the power or simply the module is a DOA. If there is something there you...
  19. [unsolved] Re: light sensing system- photoresistor connecting problem

    You need to give us more information about your goal.
    Do you want the motor speed to change based on the light conditions or you want the motor to rotate at a given speed when the light is present...
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    [chatter] Re: IT = Ingla-terra ?

    Ok, Here's my point:
    Polish happens to be my first language too. I don't see any problems with that sentence either. Therefore I undestand this guy lot better than you do (not taking about...
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    [chatter] Re: IT = Ingla-terra ?

    Masz racje Sapieha. Pewnie, ze ten koles jest z Polski... (google translator?)

    P.J. What I'm saying is that the guy may not know any better. He was asked a question and he did his best......
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    Re: Remote Voltage Monitoring of Wnd/Solar

    I guess an ideal thing would be a WiFi module that would connect to your home WiFi router. As far as I know Microchip makes WiFi boards that run a web server. Not only could you access it from your...
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    [chatter] Re: IT = Ingla-terra ?

    It's possible that English is Dr Krzysztof Szymaniec's second language. Does that matter? I think it's ok as long as you can understand what the guy wanted to tell you, right? Unless being called a...
  24. Re: Generator question: Is flickering power bad for a fridge?

    I would NOT connect these (and any other ones) capacitors across 120V AC unless you're up for a big KABOOM. Make sure that you're far away when you turn on the AC. You may film that too. It may...
  25. Thread: 28501 gps

    by alex123
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    2,817

    Re: 28501 gps

    Most GPS's (if not all) use what's called NMEA protocol. They send ASCII strings with data that you have to prase to get what you need. There's a bunch of documents that give you details on the NMEA...
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