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  1. TenderTendon

    picking components for a stir plate

    A typical 12 volt CPU cooler fan will draw 1-2 watts at full speed. A 1 watt potentiometer should be fine. If in doubt, you can cut the blades off with heavy scissors or side cutters. That will unload the motor and it will draw much less current.
  2. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    This is the latest schematic we have. I have not installed the Zener on my proto board though. The LED driver presents a load when powered, but does not pass any considerable current when off. For design purposes, the LED driver can be omitted from the circuit. RC will be a load when the MOSFET...
  3. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    Whatever you think will work...:)
  4. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    If we can get this circuit working without any glitches throughout the entire useful range of a Li-Mg battery (2.8v - 4.2v), I will probably start with making 100 of them.
  5. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    Originally, Kris wanted to use a 33 ohm charge resistor. I calculated this to cause a 14% decrease in battery run time if the flashlight was operated at medium level, which would be completely unacceptable. He then changed that value to 330 ohm, which drops that to under 2%, which is much...
  6. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    Yes, it is something Kris added in post #70. I just installed it in the LED driver to minimize the components on this switch, as I only have 14mm diameter to work with.
  7. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    Kris had already considered charging the cap with a P channel MOSFET instead of the diode, but the idea was abandoned (idea was suggested in post 60, abandoned in post 70).
  8. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    The resistor value can be increased, but not decreased, as it is already making a significant impact on the run time of the battery. In your latest drawing, LED1 does not exist. In it's place is an LED driver, that powers the LED's. The driver (as seen in post 55) has a PIC and MOSFET's in it...
  9. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    The 330 ohm resistor is built into the LED driver, not mounted on the board. The electronic switch will have no access to the (+) bat terminal, as it is at the other end of the flashlight.
  10. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    Where will the transistor get it's (+) supply from when the MOSFET is on and there is no potential across it? If your still planning on pulsing the LED off to charge, won't the 330 ohm resistor limit the charge rate?
  11. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    Congratulations and thanks for getting it working. :) The big challenge however, is still ahead. :(
  12. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    I would like to request a couple of changes to the design before this gets wrapped up. These changes will probably occur anyway for different reasons, but here are mine: 1) The Schottkey diode absolutely needs to be substituted. The one I purchased...
  13. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    Thanks Steve, very well said... Just for the record, I was never asked to apply 5v directly to the PIC. I would have done so if asked. I was asked to "power the PCB from 5 volts" and that is what I did.
  14. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    I'll see what I can do with the time I have available. Get some sleep!
  15. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    By "playing along", I meant being able to troubleshoot along side you. This micro programming is extremely confusing to me, especially when I have a CNC lathe and mill running literally 3 feet behind me and you're expecting me to get the same results as you, even though you are using different...
  16. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    OK, I changed MCLRE_ON to MCLRE_OFF. Operation is the same. Here is the asm file that is programmed on the PIC now...
  17. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    I cannot play along if we are working off different schematics. 5vdc supply gave the same results, except the averaged voltage supplying the pic while flashing was 1.85vdc and 4.77 while the LED is off.
  18. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    Adam, I could also send you a populated board, so I'm not working on apples while you're working on oranges....
  19. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    Hop, I can send you a populated board, ready to practice on. You would still need to get a genuine Microchip USB programming thingy, but this would save you some time.
  20. TenderTendon

    Microcontroller controlled by pushbutton for LED flashlight

    The problem with MPLAPXIDE was that there was no compiler selected (thanks Dan). Here is what I did. I followed Supercap"s instructions (thanks again Dan) and successfully built a new project, copying and pasting Adam's asm file into the new project. I then went and edited the asm file and...
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