THP Quarterfinalist: Low-Cost Solid State Cosmic Ray Observatory

Cosmic Rays There are a number of crowdsourced projects to put data from around the world onto the Internet, tracking everything from lightning to aircraft transponders. [aelias36]‘s entry for The Hackaday Prize is a little different. He’s tracking cosmic rays, and hopes to turn his low-cost hardware into the largest observatory in the world.

Cosmic rays are protons and other atomic nuclei originating far outside the solar system. They hit the very top of Earth’s atmosphere at a significant fraction of the speed of light, and the surface of the Earth is frequently sprayed with particles resulting from cosmic rays. Detecting this particle spray is the basis for all Earth-based cosmic ray observatories, and [aelias] has figured out a cheap way to put detectors in every corner of the globe.

The solution is a simple PIN diode. An op-amp amplifies the tiny signal created in the diode into something a microcontroller can use. Adding a GPS module and an Ethernet connection, this simple detector can send time, position, and particle counts to a server, creating a huge observatory with crowdsourced data.

The detectors [aelias] is working on isn’t great as far as cosmic ray detectors go; the focus here is getting a lot of them out into the field and turning a huge quantity of data into quality data. It’s an interesting project, and the only one with this scale of crowdsourcing we’ve seen for The Hackaday Prize.

You can check out [aelias]‘ entry video below.


SpaceWrencherThe project featured in this post is a semifinalist in The Hackaday Prize.

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Reverse engineering the die of a ULN2003 transistor array

uln2003-die-reverse-engineering

We’re no strangers to looking at uncapped silicon. This time around it’s not just a show and tell, as one transistor form a ULN2003 chip is reverse engineered.

The photo above is just one slice from a picture of the chip after having its plastic housing remove (decapped). It might be a stretch to call this reverse engineering. It’s more of a tutorial on how to take a functional schematic and figure out how each component is placed on a photograph of a chip die. Datasheets usually include these schematics so that engineers know what to expect from the hardware. But knowing what a resistor or transistor looks like on the die is another story altogether.

The problem is that you can’t just look at a two dimensional image like the one above. These semiconducting elements are manufactured in three dimensions. The article illustrates where the N and P type materials are located on the transistor using a high-res photo and a reference diagram.

If you want to photograph your own chip dies there are a few ways to decap them at home.

Using diodes and transistors as solar cells

When you get down to it, solar cells aren’t much different from the diodes and transistors in your parts drawers or inside your beloved electronics. They’re both made of silicon or some other semiconductor, and surprisingly can produce electricity in the presence of light. Here’s two semiconductors-as-solar panel projects that rolled into the tip line over the past few days.

[Steven Dufresne] cut open a 2N3055 power transistor to expose the semiconductor material to light. In full sunlight, he was able to produce 500 millivolts and 5.5 milliamps. In other words, he’d need around 5000 of these transistors wired up to turn on a compact fluorescent light bulb. A small calculator has a much lower power requirement, so after opening up five transistors he was able to make a solar-powered calculator with a handful of transistors.

[Sarang] was studying solar cells and realized a standard silicon diode is very similar; both are p-n junctions and the only real difference is the surface area. He connected a 1N4148 to a multimeter and to his surprise it worked. [Sarang] is able to get about 150 millivolts out of his diode with the help of a magnifying glass. While he doubts his diode is more efficient than a normal solar cell, he thinks it could be useful in low-cost, low power applications. We’re thinking this might be useful as a high-intensity light detector for a solar cooker or similar.

After the break, you can check out the videos [Steven] and [Sarang] put up demonstrating their solar cells.

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Magnetic Movie


Magnetic field lines may be invisible to the naked eye, but they behave in ways that would amaze us if only we could see them. [Ruth Jarman] and [Joe Gerhardt] from Semiconductor wanted to make them visible for everyone, so they produced Magnetic Movie, a film that combines animations, theoretical models, and actual VLF recordings of the entire Earth’s magetic forces to create a film that shows magnetic fields moving and jumping through the air in living color.

The film is part art project and part scientific experiment, but we can enjoy it on both levels, as watching the path and motion of magnetic field lines is both beautiful and informative. Get a glimpse for yourself after the break.

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