A very tiny gamma ray detector

gamma

When you think of a radiation detector, you’re probably thinking of a Geiger tube and its high voltage circuitry. That isn’t the only way to measure gamma radiation, though, and [Alan] has a great circuit to measure even relatively weak radiation sources. It uses a very small photodiode, and draws so little power it’s perfect for projects with the smallest power budgets.

The detector circuit uses a miniature solar cell and a JFET wired up in a small brass tube to block most of the light and to offer some EM shielding. This, in turn, is attached to a small amplifier circuit with a LED, Piezo clicker, and in [Alan]‘s case a small counter module. The photodiode is actually sensitive enough to detect the small amounts of gamma radiation produced from a smoke alarm americium source, and also registers [Alan]‘s other more powerful radioactive sources.

The circuit only draws about 1mA, but [Alan] says he can probably get that down to a few micoAmps. A perfect radiation sensor for lightweight and low power applications, and gives us the inspiration to put a high altitude balloon project together.

Built-in hex editor unlocks plasma TV features

[Nick] tipped us off about a guide to unlock extra features on Panasonic televisions. The hack works on the G10 models of plasma TVs and uses the service menu to gain access to the EEPROM memory. With a few quick steps you can change some data with a built in hex editor, unlocking several new settings menus, or bricking your entertainment centerpiece. We’ve seen some Samsung TV hacking in the past and hope that with increased processing power in today’s models we’ll someday see consumer TVs available with open-source firmware so that we can integrate of our favorite entertainment software.

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