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  1. hevans1944

    Level shifter

    Just now tried that editor. Very spiffy! How do you get the background grid to appear with the schematic when exporting the drawing?
  2. hevans1944

    Hall effect sensor trigger LED

    Your circuit diagram does not agree with the datasheets for either the Hall sensor or the Schmitt trigger. See attached datasheets. The Hall device is a current-sinking output, which means you supply a voltage supply to the output through a current-limiting resistor. The Schmitt trigger has no...
  3. hevans1944

    Level shifter

    All of the inputs to the dual D-type flip-flop, SN74HC74, must be CMOS level inputs: -0.5 V < Vi < (Vcc+0.5) V For a 5 VDC supply this generally means all inputs must be between ground and +5V. The easiest way to guarantee this with ±12 VDC outputs from your UA741 op-amp (which is NOT a...
  4. hevans1944

    Solar charging.

    That is absolutely true, I don't know where he (or she) lives. Feel free to jump in with an estimate of your own. Maybe a 100 W panel is a wee bit more than is required if the energy requirement really is less than 50 watt-hours per day... but it will work. Read near the bottom of the original...
  5. hevans1944

    Need to find a way to do different functions basedon incoming voltage

    Never mind. I see the TRANSISTOR (a modern invention in no way related to RELAYS) shorts out the red LED when the green LED is on. Good call, @Colin Mitchell.
  6. hevans1944

    Solar charging.

    Sure it will. You just need a boost converter/charger. Nonsense. Even a 1.5 V panel providing sufficient current to a boost converter will work. Yeah, you need a diode, maybe a choke, some more diodes, possibly some Schottky diodes, some MOSFETs, and an Integrated Circuit Charge Controller...
  7. hevans1944

    Microcontroller controlled by pushbutton for LED flashlight

    Thank you! I will send you a PM with my address and telephone number when I am ready for that. Meanwhile, Adam seems to have the best opportunity now to figure out what is wrong since I haven't read his code yet. I do have the test equipment (oscilloscope, five-digit VOM, etc.) to probe a...
  8. hevans1944

    Solar charging.

    Your circuit requires 205 mA (max) and 12 VDC for a "couple of weeks," so the power required is 2.46 watts (max) continuously during that time. The panel you found provides 150 mA @ 7.5 VDC or 1.125 watts, but only when fully illuminated by the sun. So this panel (alone) will not provide enough...
  9. hevans1944

    Hello to everybody!

    Welcome to Electronics Point! Besides being "an Italian student" are you also living in Italy? If so, please thank the fine people there who invented the Arduino and made it "open source" for the whole world to enjoy. It would also be nice if you added your country of origin to your profile.
  10. hevans1944

    how to design an AM transmitter and AM receiver?

    Are you serious? What is your background and experience in electronics? Why not just purchase an AM transmitter and AM receiver? What frequency range do you want to transmit and receive over? How much power will the transmitter radiate? Licensed or un-licensed operation? Do you want to park a...
  11. hevans1944

    Where is a good location to connect a 3-Volt relay?

    You are eternally welcome. Have fun, stay safe!
  12. hevans1944

    Microcontroller controlled by pushbutton for LED flashlight

    I can appreciate that. Gotta put food on the table first. Learning how to program is a luxury for those of us with some time on our hands. I don't keep track of the hours I spend on my electronics hobbies or trying to help others in this forum: every one of those hours spent is a blessing, and I...
  13. hevans1944

    Led Lamp

    Yeah, glad you mentioned that. It appears that @Jeffro may somewhat lack experience in the area of safe electronics construction... just going by the conversation so far.
  14. hevans1944

    Microcontroller controlled by pushbutton for LED flashlight

    I sure hope so. I sweated bullets last night waiting for all 360 Mbytes to download, hoping my Time-Warner wiseband wouldn't decide to throttle or cut me back to ADSL speed for no other reason than they can. I would upgrade from "Turbo" to 50 Mbps, but even that isn't guaranteed. So now I have...
  15. hevans1944

    Microcontroller controlled by pushbutton for LED flashlight

    What machines and which OS are you using? I am using an HP Pavillion-series laptop running 64=bit Windows 7 Professional and have had no problems running 32-bit programs. I will download MPLAB later this week to see what happens in my environment and let you know what I find out. I today...
  16. hevans1944

    Help with time counter for wildlife research

    I like your attitude! And it appears you have made some progress with electronics since your previous thread several years ago. The technology available today is truly amazing, and easily accessible to the DIY amateur. Component costs are minimal (a few cents for many microprocessors) and...
  17. hevans1944

    inductor filter

    Selvam, I must agree with @davenn that the problem is way beyond your pay grade and responsibilities... and I am non-Indian and retired, so not in a position to help. However, I don't mind voicing opinions. And I can appreciate the idea that someone "working in the trenches" might come up with a...
  18. hevans1944

    Counter Circuit Troubleshooting

    Download the datasheets for each of the integrated circuit components. There will be a diagram on each datasheet showing the pin numbers, their name or function, and a simplified block diagram of what the pins are connected to inside the integrated circuit. Using this information and the wiring...
  19. hevans1944

    Microcontroller controlled by pushbutton for LED flashlight

    I love this thread. What a wonderful tribute to the memory of @KrisBlueNZ that the flashlight project will soon be completed!
  20. hevans1944

    inductor filter

    There is no such thing as an "inductor filter circuit for blocks ac". The most an inductor will do is attenuate ac, not block it. What exactly are you trying to do?
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