Member Since: June 4, 2009

Country: Mexico

  • Well... if you mix an element that can be easily ionized in the paint. That way you'd be able to detect the ionizing radiation from the paint probably. I don't know for sure as I don't have much chemistry knowledge. I would say, that be one expensive cable detector or whatever you want. Anyway, the Geiger counter can detect many things, whats important is you knowing what you are detecting depending on the energy spectrum of the beta particles. I could attach a small drawing/diagram of how I would build my beta ray spectrometer by using stuff sold at sparkfun.

  • If you attach an electromagnet on the side of the geiger muller tube and have the radioactive source between the tube and the electromagnet, you can, by varying the magnetic field (from small to big preferably), do a beta spectroscopy. Depending on the magnetic field intensity, different energy particles will go in an half circle trajectory around the electromagnet and hit the geiger counter. Thus, by counting a time T for each energy level, you can get the specter of your source and thus, analyze what the radioactive source is. A geiger tube like this will only tell you if there are beta particles present (electrons or positrons). Also, beta particles shouldn't be harmful to the human body, gamma particles are the ones I would fear.

  • If you use an electromagnet to bend the path of the beta particles to go into the Geiger M?ller tube, you can analyze the energy spectrum of the beta particles (By applying different magnetic field intensities different particles of certain energy levels will be deviated to the Geiger counter). With the spectrum you can identify the element emitting the radiation. To detect gamma radiation I would use a scintillator (Which I actually have).

  • What about optical isolation? I'd try an 4N25 if the device isn't 5V tolerant. The only problem is that the 4N25 needs something like 50mA to work and maybe you'd need a transistor before to get that much current. Anyway, I don't know if it will work for I2C, I made it work with serial communication.

  • Hi there! I'd go with the MOSFET. In a recent project I used a BJT in a similar configuration and worked perfectly fine.

  • It's got some good sound and looks quiet simple to make. Perfect, as my amp is very heavy. I think It's an excellent idea.

  • Hi, this is a good tutorial. There is just one thing, I think I'd use a thyristor instead of a relay, because of the power consumption. I would also add some optical isolation to not risk my MCU. Anyway, I think it's a good tutorial.

  • Well, this kind of 5V source isn't the type I'd use. It wastes almost 50% of the power. This means that your 9V battery will last almost the half it should with a well made 5v source. There are some IC's from maxim that achieve high efficiencies. I've learned that in battery powered projects one should be as efficient as possible. Anyway, I think it's a well made tutorial and it's a good starting source for one's first projects. By the way, you are so right about the PTCs. I've seen several of my most sensitive IC's smoke to death in an instant and not because of short circuits. When using batteries one has to take into account the short circuit current it gives. It may be too small (CR2032 for example) or too high and may give trouble because there's no limit. PTCs are life savers.

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