A No-Solder, Scrap-Bin Geiger Counter For $15

Scenario: your little three-hour boat tour runs into a storm, and you’re shipwrecked on a tropic island paradise. You’re pretty sure your new home was once a nuclear test site, but you have no way to check. Only your scrap bin, camera bag, and hot glue gun survived the wreck. Can you put together a Geiger-Müller counter from scrap and save the day?

Probably not, unless your scrap bin is unusually well stocked and contains a surplus Russian SI-3BG miniature Geiger tube, the heart of [GH]’s desert island build. These tubes need around 400 volts across them for incident beta particles or gamma rays to start the ionization avalanche that lets it produce an output pulse. [GH]’s build uses the flash power supply of a disposable 35mm camera to generate the high voltage needed, but you could try using a CCFL inverter, say. The output of the tube tickles the base of a small signal transistor and makes a click in an earbud for every pulse detected.

You’ll no doubt notice the gallons of hot glue, alligator clips, and electrical tape used in the build, apparently in lieu of soldering. While we doubt the long-term robustness of this technique, far be it from us to cast stones – [GH] shows us what you can accomplish even when you find yourself without the most basic of tools.

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Raspberry Pi Camera Flash

The Raspberry Pi Camera is a great tool; it allows projects that require a camera to be put together quickly and on a budget. Plus, having a Linux back end for a little processing never hurt anybody. What can be difficult however, is imaging in low light conditions. Most smartphones have an LED flash built in for this purpose. [Wim Van Gool] decided to follow suit and build an LED flash for the Raspberry Pi.

The project consists of a custom PCB with surface-mount LEDs in an attractive concentric layout. This is a good way to get a nice even distribution of light, particularly when taking photos close up. The board is designed around the Texas Instruments TPS61169 LED driver, which is controlled by a PWM signal from the Raspberry Pi. The flash mounts as a Raspberry Pi HAT, and there’s a hole routed in the centre to allow the camera to fit in nice and snug when using standard 11mm standoffs. It might seem simple, but it’s an impressively tidy piece of engineering and a testament to [Wim]’s abilities.

The Raspberry Pi Camera turns up in all sorts of projects — like these far-seeing PiNoculars.

Disposable Camera Flashes Live Again

Aiming to improve the image quality of the photos on his website, [Jean] needed an external flash unit.

ep-026-0280-960Say what you will about disposable cameras, but the fact that they were mass-produced, and are now nearly obsolete, means they are an absolute treasure trove of electronics components when you can buy them for dirt cheap. So [Jean] decided to turn a few of his disposable cameras into an external flash system for his DSLR (Translated).

He started by taking apart a Kodak digital camera and examining the circuit board. KEY1 enables the charging of the capacitor (the camera ON switch) and SW1 is located under the shutter-release.

Now all he had to do was replace SW1 with an electronic trigger from his DSLR.

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