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  1. hevans1944

    Ballast for UVC Lamp

    I read the same thing from the flyer. I would suggest you contact the ballast manufacturer and see if they can help you.
  2. hevans1944

    Tic Tac Toe, Human vs Machine using flip flops

    You might want to start here for a tutorial on recursive use of the minimax function. And an actual game built on the tutorial can be found here. Good luck building a finite state-machine with gates and flip-flops. I saw this done at a science fair presentation fifty-something years ago, using...
  3. hevans1944

    I Need Some Help With a Level Indicator Project

    Not sure there is any practical difference. The one Adam linked to is made by Analog Devices, the one I linked to is made by Freescale. Both are sold mounted on circuit board with supporting components by Adafruit. The ADXL345 claims 13-bit resolution while the MMA8451 claims 14-bit. You would...
  4. hevans1944

    I Need Some Help With a Level Indicator Project

    What!? Four bucks for a bubble level plus a Dollar Store mirror? Where's the technology? Where's the fun? Where's the smartphone with the bubble-level app? Why not ditch the mirror and hire a helper to read the bubble level and give hand-signals to the person in the cab? Help keep an immigrant...
  5. hevans1944

    I Need Some Help With a Level Indicator Project

    The MEMS accelerometer I linked to in post 18 needs some support circuitry. Use this one with the Arduino Uno.
  6. hevans1944

    I Need Some Help With a Level Indicator Project

    Tongue in cheek? How absurd, you know I only give my best advice here.:cool: As for power, I actually think my idea could work if the operator in the cab had keen vision and could see the smartphone screen without optical aid. However, on second thought, it might require building a box around...
  7. hevans1944

    High Precision LED Absorbance Measurement

    Probably doesn't matter if LED is connected with shielded wire, since this is a high-level analog power signal. It would take an extraordinary amount of external "noise" coupling to the twisted pair to affect the LED output. Still, some small diameter coax, if you can find a short piece laying...
  8. hevans1944

    I Need Some Help With a Level Indicator Project

    If you have an Android smartphone laying around, with the Best Level app installed, you could build a little shelf and attach it to the auger with a mirror at a 45 degree angle to view the cellphone screen from inside the cab... maybe mount a cheap telescope in the cab for a better view, use...
  9. hevans1944

    I Need Some Help With a Level Indicator Project

    Impossible. I already have this app on my Galaxy 4 smartphone. Or, maybe you get a royalty every time I use it?
  10. hevans1944

    I Need Some Help With a Level Indicator Project

    I would get fancy and make the LCD display a two-axis bubble level. Center the bubble then auger away. Maybe communicate from the sensor mounted on the auger to the display in the cab with Bluetooth. How are you going to get power to the sensor? Battery operated? Tell me the brand so I can...
  11. hevans1944

    please help

    High when a valid pair of tones is detected.
  12. hevans1944

    High Precision LED Absorbance Measurement

    Many years ago, before the availability of delta-sigma A/D converters with twenty-something bits of resolution, I was involved with micro-densitometry. Using a stable incandescent light source, channeled down to a micro-meter sized spot with proprietary techniques, we illuminated fine-grain...
  13. hevans1944

    High Precision LED Absorbance Measurement

    Virtually all absorption measuring instruments include a reference path that alternates with the measuring path to the detector. As @GPG stated, this is often just a rotating mirrored disk with open spaces to either pass the beam or reflect it. Seems like a lot of complexity to just measure...
  14. hevans1944

    High Precision LED Absorbance Measurement

    You are in for an adventure in analog signal processing. The reverse leakage current (dark current) of your photo-diode is quite small and probably accounts for a goodly part of its cost. The responsivity is also good at 100 mA per watt (minimum) at 365 nm. However, this is a broadband sensor...
  15. hevans1944

    High Precision LED Absorbance Measurement

    I can't really take credit for this idea. My mentor at the time, perhaps ten or fifteen years my senior, suggested it because I didn't know diddly about photodiodes at the time. The Nernst glower was the central figure in an infrared radiation source that we built using a salt lens (NaCl) to...
  16. hevans1944

    High Precision LED Absorbance Measurement

    I once needed a similar arrangement to control the emission temperature of a Nernst glower. The problem was my photodiode started at room temperature and then got hotter because of visible and infrared radiation from the glower. To compensate for this huge temperature excursion, I used two...
  17. hevans1944

    Voltage sensor 10-15v

    @Javasirc : Since you "can't tamper with or modify anything," can I assume you are going to power both the cooler (a Peltier heat-pump + a fan to circulate cool air?) and the Arduino from a cigarette lighter receptacle on the truck? May I also assume that power (from the battery) is available...
  18. hevans1944

    Including header files

    @chopnhack : It's all relative. Maybe you aren't up there with @Supercap2F yet, but you are way above where I am as a C programmer. Thanks for explaining for @Sadlercomfort how to use an #include statement. If I ever start playing with some of those really sophisticated PICs you are dipping...
  19. hevans1944

    Sony reel to reel tape recorder inquiry

    And if you folks think this reel-to-reel audio tape recorder is complicated, take a close look at a vintage computer reel-to-reel tape drive peripheral with vacuum columns to control tape tension. Those puppies could spin up a nine-inch reel of tape to warp speed in a fraction of a second and...
  20. hevans1944

    Voltage sensor 10-15v

    Well, I guess if you have talent enough to build a digital cooler for your truck, you should be able to search Google and Amazon for the parts you need. Good find Martin! But what the hell is a "digital cooler" and why should it only run when the truck engine is running? And why does he need to...
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