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  1. BobK

    Problem with positive pre-sensitized board exposure solved

    I had been using the positive presensitized PCBs for a while, using a kit I got from MG Chemicals, which included what is basically an under kitchen counter fluorescent light for exposure in a light box I made. I was getting really good results with a 12 minute exposure. Then, after not using...
  2. BobK

    "Repair" mystery

    This year, for the holiday season, the lovely wife Morticia and I put these nifty LED candles in each window of our house. They have a flickering LED "flame" on top, two AA batteries, a switch on the bottom. The bulb screws into the candle shaft and has a circle in the middle of the bottom...
  3. BobK

    Time to start building grow lights!

    Today, in my state of Massachusetts, it became legal to grow pot (indoors only) for personal consumption. I think the market for grow lights is about to explode! Bob
  4. BobK

    Another find at the Habitat for Humanity Restore

    A good sized variac, with the lovely wife Motricia's foot for size comparison: And some impressive specs: This is from the same place with the old Tectronix scope. Both were from a movie set that was donated. Bob
  5. BobK

    Looking for a used scope?

    I found this at the Habitat for Humanity store. It is Humongous! Over 2 ft deep and maybe 14" x 18" on the front. And still, they needed a separate power supply (the box at the bottom of the cart). Marked $175 and labelled as "Antique Oscilloscope." It is dual trace, but only one probe...
  6. BobK

    Pokemon Go

    Anyone else playing? I love that fact that the best thing to defeat an electric type Pokemon is a ground type! Bob
  7. BobK

    Partially shaded solar panels

    The lovely wife Morticia and I just spent a couple of hours with a solar energy salesperson. One thing he said strikes me as not being true. He claims that if your roof panels are shaded by trees (all deciduous in our case), you get the same loss of power in the winter, when the trees are bare...
  8. BobK

    Apple vs the FBI

    Couldn't they simply remove the flash chip or chips from the device and read them something other than an iPhone? I doubt that the program that erases everything after 10 wrong keys are entered would be inside the flash chip. The data is presumably encrypted, but there are only 10000 possible...
  9. BobK

    Why I prefer electronics to plumbing

    This morning, I found that the drain for the washing machine had cracked leaving water all over the floor. A typical plumbing emergency. So naturally, I went to my well-stocked hat rack and put on my plumbing hat. The connection into the drain pipe was old iron pipe. The old fitting did not...
  10. BobK

    Wish me luck

    My workplace (Intel in Hudson Massachusetts) is shutting down the FAB facility (I am not affected because I am engineering unrelated to the FAB.) So they are selling off some equipment at ridiculous prices. They will put the names of all who bid on the items in a hat and pull out the winner...
  11. BobK

    Build a device from a Schematic (Production PC board)

    BobK submitted a new Showcase Item: Build a device from a Schematic (Production PC board) Read more about this showcase item here...
  12. BobK

    Build a device from a schematic (DIY PC board)

    BobK submitted a new Showcase Item: Build a device from a schematic (DIY PC board) Read more about this showcase item here... Bob
  13. BobK

    My Wearable Device

    BobK submitted a new Showcase Item: My Wearable Device Read more about this showcase item here...
  14. BobK

    Smoke detector mystery

    I have a smoke detector that is in a precarious place, on a sloping ceiling high above a flight of stairs. I cannot easily use a ladder to reach it because of the stairs, so the way I get to it to change the battery is by placing a sheet of plywood across the stair railing and a step ladder on...
  15. BobK

    Photo-resist PCB help

    I have just tried my first attempt at a photo-resist PCB. The results, shown here are not quite ideal. All of the traces should be the same size at 0.12 in. Obviously some of them have bled out to the point where clearances are not met, while others look quite sharp. The image on the left is...
  16. BobK

    Snowstopper

    Please help. I want to make an electronic device that diverts snowstorms around my city. I have made many things with LEDs. Bob
  17. BobK

    Intel enters the Arduino market

    Interesting. an Intel Architecture Arduino compatible board. http://www.intel.com/content/www/us/en/do-it-yourself/galileo-maker-quark-board.html disclaimer: I am an Intel employee, but I thought this was of enough interest to the forum that it should not be interpreted as advertising...
  18. BobK

    Building PCB from schematic

    Hi all, I have finished my project log for building a professionally made PCB as stated in Steve's stcky in this forum. https://www.electronicspoint.com/build-device-schematic-production-pc-board-t257051.html If you read through it you will see that I received (unexpectedly) 4 boards...
  19. BobK

    You would think Boeing would know better

    Lithium Batteries Central to Boeing's 787 Woes It's not like there has not been any press about the dangers of Li Ion batteries... You would think Boeing would have the expertise and motivation to handle them correctly, but apparently not. Bob
  20. BobK

    Signs of Chinese progress

    An actual fortune that I got in a cookie at a Chinese restaurant.
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