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  1. chopnhack

    UV LED PCB Lithography Exposure Unit

    Wish me better luck! I am going to use the diy dry film that gets laminated to the blank pcb. This sandwich is then exposed to the uv lights. Interestingly enough, the LED's I got are predominantly 390-395NM wavelength, barely UVA. Although longwave radiation of this type is harmful to the skin...
  2. chopnhack

    How can we Improve EP in 2017?

    I would like to also add that the project log section could be changed to allow for updates with photos. As it stands, you have to edit the original post to append new photos and adding text is not easy either.
  3. chopnhack

    UV LED PCB Lithography Exposure Unit

    chopnhack updated UV LED PCB Lithography Exposure Unit I found it interesting that the drive was not a stable voltage source, it seemed to bounce around between 58vdc and 80v! Even when taxed with twenty 1 watt LED's is seemed capable of providing the power. I haven't inlined my multimeter yet...
  4. chopnhack

    GPS NMEA, Failover Circuit upgrade attempt.

    I see it now!
  5. chopnhack

    GPS NMEA, Failover Circuit upgrade attempt.

    Where did you find the datasheet? The one I found doesn't show your particular current level, but all the other models show much lower resistances. https://www.elsin.ru/pdf/JK250series.pdf
  6. chopnhack

    How can we Improve EP in 2017?

    It would be pretty cool to have a chat room with the ability to automagically paste the contents to an associated thread for folks working on lengthy projects that need fast face time with other members, but still allow it to be useful to the rest of the community. Also, like we discussed...
  7. chopnhack

    LED Wiring

    Great point to raise Steve - I have a 12v adapter (transformer inside, not switching) and with no load it registers 28vdc initially and settles at 21vdc on my multimeter. Under very light load (less than 30mA) its about 14 volts!
  8. chopnhack

    Happy New Year!

    I hope everyone is enjoying the New Year or the New Year countdown, depending on where in the world you are! Enjoy, be safe and see you all in 0x7E1 :p:D
  9. chopnhack

    Concept Delay Circuit [Block Diagram]

    Not quite, you have the output of your bistable feeding the Vcc of your R-C and monostable 555 circuits. Your output needs to go to the trigger of the monostable and likewise for the astable phase. But otherwise logically I can see what you are trying to do - 1st 555 gives a signal which is then...
  10. chopnhack

    LED Wiring

    Can you remove one battery and put a multimeter set to read current in series with the battery pack and removed battery? That should answer your question regarding what current is being drawn. I would leave the resistors that are built in and simply feed the power supply to each LED 'unit'. The...
  11. chopnhack

    Mooshimeter

    Every hear of this one? Looks great for many applications, really neat!
  12. UV LED PCB Lithography Exposure Unit

    UV LED PCB Lithography Exposure Unit

    Received some goodies in the mail from our brethren in the Far East today :p I have never tried photolithography for producing PCB's, so I figured for a few bucks, I could give it a go. I used twenty 1w 395nM UV emitting LED's mounting on aluminum PCB which I then mounted with a heat sink epoxy...
  13. chopnhack

    UV LED PCB Lithography Exposure Unit

    chopnhack submitted a new Showcase Item: UV LED PCB Lithography Exposure Unit Read more about this showcase item here...
  14. chopnhack

    Laser Rust Removal

    I wonder how cold the casting gets while being sand blasted with dry ice? I wonder how abrasive that is, the video is just showing degreasing and not rust removal per se. Good find though! Never heard of this removal method either :) Way friendlier than the solvents we used to use in the shop to...
  15. chopnhack

    Laser Rust Removal

    Wow, I had never seen this before!
  16. chopnhack

    Old IC chips

    The SNJ54LS30J is a 8 input NAND gate. Largely replaced by modern mcu's. If they are real gold, the value is in the weight of the element.
  17. chopnhack

    Laser Beam Timer

    Some broad strokes if you like: I would approach this project with the assumption that I could attach a microswitch on the lever that activates the trap door. This switch would be the input to a microcontroller of some sort (arduino or purpose built chip). The microcontroller would then need to...
  18. chopnhack

    Samsung KS7000 VS KS8000

    Honestly, TV shopping can no longer be done on specs... I thought it would be simple, look for the best specs and go pick one up... furthest from the truth. You really need to see them in person to compare. If you have a large electronics retailer, pop in and see them, preferably side by side...
  19. chopnhack

    Short Range Locator

    Tile?
  20. chopnhack

    Solar powered plant waterer

    Hi Henry, and welcome to EP. I think you are off to a good start with the suggestions you have received. The 'brains' of your project could be something as simple as an arduino with a transistor to open your solenoid (the arduino can probably supply no more than ~25mA, thus the transistor). You...
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