Photosensitive

There are only a few more days until The Hackaday Prize semifinalists need to get everything ready for the great culling of really awesome projects by our fabulous team of judges. Here are a few projects that were updated recently, but for all the updates you can check out all the entries hustling to get everything done in time.

Replacing really, really small parts

acc The NoteOn smartpen is a computer that fits inside a pen. Obviously, there are size limitations [Nick Ames] is dealing with, and when a component goes bad, that means board rework in some very cramped spaces. The latest problem was a defective accelerometer.

In a normal project, a little hot air and a pair of tweezers would be enough to remove the defective part and replace it. This is not the case with this smart pen. It’s a crowded layout, and 0402 resistors can easily disappear in a large solder glob.

[Nick] wrapped the closest parts to the defective accelerometer in Kapton tape. That seemed to be enough to shield it from his Aoyue 850 hot air gun. The new part was pre-tinned and placed back on the board with low air flow.

How to build a spectrometer

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The RamanPi Spectrometer is seeing a lot of development. The 3D printed optics mount (think about that for a second) took somewhere between 12 and 18 hours to print. Once that was done and the parts were cleaned up, the mirrors, diffraction grating, and linear CCD were mounted in the enclosure. Judging from the output of the linear CCD, [fl@C@] is getting some good data with just this simple setup.

Curing resin and building PCBs

[Mario], the guy behind OpenExposer, the combination SLA printer, PCB exposer, and laser harp is chugging right along. He finished his first test print with a tilted bed and he has a few ideas on how to expose PCBs on his machine.

You don’t need props to test a quadcopter

blades Goliath, the gas-powered quadcopter, had a few problems earlier this month. During its first hover test a blade caught a belt and bad things happened. [Peter] is testing out a belt guard and tensioner only this time he’s using plywood cutouts instead of custom fiberglass blades. Those blades are a work of art all by themselves and take a long time to make; far too much effort went into them to break in a simple motor test.

Making your own boards at home is among the heights of achievement for home tinkerers, and one fraught with frustration. The toner transfer process requires carefully peeling away layers of photo paper, and milling your own circuit boards is an exercise in complexity. One of the best options is using photosensitive copper boards, but this requires exposing the masked-off copper to fairly intense UV light. A UV exposure box is a wonderful project, then, and something [Carlo] just about has wrapped up.

The first portion of [Carlo]’s build involved placing 135 UV LEDs on a piece of protoboard. This UV source eats up a surprising amount of power; [Carlo] is using 12V for the supply, so an old industrial power supply is more than capable of dishing out the 1.5 Amps required for the build.

Next, [Carlo] needed a timer for his exposure box. He settled on a design based on an ATMega8 turning a high voltage transistor on and off with a character LCD for the user interface. A few buttons allow [Carlo] to set the countdown timer, after which the LEDs turn on for a set period of time.

All this was packaged into a small box [Carlo] picked up from Ikea. It’s a very useful build, and judging from the video after the break, extremely easy to use.

Continue reading “Ikea Provides A Great UV Exposure Box” →