EEVblog #494 – Mailbag

USB Serial Module:
DSRB-88 Geiger Counter:
Induction Coin Shinker:
DE0-Nano FPGA Development Board:

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  1. If you have any granite around you’ll likely get a read off that.

    • Drywall (plasterboard) would be another good one to test, though it’s produced in various purities. I’m not sure how radioactive they allow it to be in Australia.

  2. i would LOVE to see some FPGA videos i have been meaning to learn them

  3. Thanks for reading my post card, Dave. Glad you like the scenery from Glacier National Park.


  4. I can’t wait for some FPGA videos. I’ve been wanting to get into those.

  5. Hello David.

    Geiger counters can detect X-Ray, emitted by RX tubes used for dental radiography, for example.
    Some watches have dials or pointers that glowed in the dark without prior exposure to light. These were made with radioactive material, an ink-based tritium. If the display (around 6 hours) there is a letter “T” means Tritium. When it says “T<25" means that radiation is less than 25 millicuries. The inscription "R" or "Ra" means that radium was used, and this is very dangerous and it was banned.
    Many smoke detectors sold in many countries using americium 241 in the form of americium dioxide (AmO2). With approximately 0.9 microcurie.
    Another source of radiation are "radioactive lightning rods", probably banned everywhere today. These were manufactured in Brazil until 1989 and also used americium 241 (Am-241) or Radium-226 (Ra-226) with 1.5 millicurie. Unfortunately there are still thousands of them around the country, including thrown into landfills…

    Not sure about these numbers.

    Forgive my English

  6. Thumbs up for FPGA!!!

    Actually this was a nice straight forward mailbag. But I’m ashamed to admit that I kind of like your way of ranting for several minutes about one engraved pen. So that would be still cool once in a while.

  7. Let’s see more FPGA introduction / tutorial stuff!

    I’ve just started playing around with a Lattice ECP33E board. Mught need some help with the basic VHDL stuff here!

  8. Yes, I’d like to see a basic intro to FPGAs just to get some idea of how easy/hard it is to get into these. I understand the learning curve is pretty darn steep. As a thought for a demo design to do with FPGA, how about a simple 8/16 channel logic analyzer displaying results on a recycled VGA display? Don’t know if that’s a good example or not.

  9. Yes! I want to learn about FPGAs! I understand that they’re better at some stuff than microcontrollers, but I think seeing it in action would help it sink in. Anxiously waiting!

  10. Up voting for more videos on FPGAs. FPGA Fundamental Fridays!

  11. I’ve been meaning to buy a DE0-Nano for 6 months as I want some practical FPGA experience. I did a couple of lab sessions at university (10+ years ago) and a 5-day Doulos training course for a project that was cancelled (5 years ago).

    I remember that during the training course I found it very strange coming from a microcontroller background as the FPGA doesn’t execute code in the order that it’s written. It all happens at the same time… apart from the deltas and races and the fact that they can change each time you recompile :-s Hmmm…

    I’d love to see some videos on this.

  12. I love seeing all that Oregon stuff. Brings a tear to the eye. (I hail from Corvallis, OR, b.t.w. We are oddly particular about pronunciation. I think it’s because national news in the US insists on mispronouncing EVERYTHING!)

    I would also love seeing more intro to FPGA stuff. Mike and Jerri will still take the cake for the “holy shit, that’s amazing” FPGA work, but I desperately want to get started.

  13. The random firings of the radiation detector are caused by cosmic ray muons. These originate in the upper layers of the atmosphere when cosmic rays (high energy particles from outside the Solar System, typically protons) collide with air molecules.

    Smoke detectors use alpha sources. Alpha particles are not very penetrating (even a sheet of print paper will stop most of the radiation, let alone making it through layers of plastic and into the Geiger tube…). Try torbernite, if you can get it.

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