Archive for August, 2011

DIY :: Geiger Counter, making your own graphs

I’ve got a few questions about the geiger graph plots and how to make them. Here’s a short explanation for those without extensive computer background. Personally I prefer using RRDTOOLS to plot any data graphs, but the installation under Windows might be a bit too difficult for the average windows user. Anyway, if you plan to user RRDTOOLS, here’s the download link, and don’t forget you’ll need to install CYGWIN as well. Japanese users might appreciate someone already had translated the manual.

For everybody else, I think the easiest way is to use Excel/Chart or OpenOffice to create pretty pictures in no time.

First, you have to launch your favourite terminal application and get some data from the (USB-)serial port and copy it with (Ctrl/C) or any other available technique. This is the data you’re going to make a graph from.

Open Excel or any other spreadsheet software and paste the data into it. Don’t forget to set “separators” to spaces or the data won’t get separated into the different columns.

In the column just before the data, enter two consecutive time values (13:30 and 13:31, for example), select them and drag black square with the mouse to fill the whole column with the time values.

Finally you may select the time and data columns together and use Chart function to draw a pretty char of your data. There are plenty of settings to adjust and make it look just the way you like it.


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DIY :: Geiger Counter, high speed readings

This is new, totally reworked board which can accomodate any tube, from SI-3BG through SI-37/39G upto SI-1G and even SBM-20, though the last one is a bit too large and leaves tips hanging off the board. The tube on the picture is SI-39G. High voltage generator is now controlled from the microprocessor, instead of fixed setting as on previous boards and also there’s a noisy buzzer, which ‘ticks’ just like the original geiger counter.

New software has changed a lot, now includes voltage controller, buzzer support and fast screen update. The data over USB is still sent once a minute, but the LCD display is now updated every 4 seconds (2-3 seconds were also possible, but seemed to be overkill) with the data of the last minute. Instead of fixed 1 minute intervals, this version uses “sliding 1 minute window” to calculate the value. There’s no need anymore to wait for full 1 minute to see readings go up after introduction of some radiation source, the change is obvious and imminent. Though, on the down side, this fast pace could be a bit disconcerting to some users.


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