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sc2 when it all comes together

sc2 when it all comes together The front without front:

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The buttons are, first column left to right isotope pointer left isotope pointer right cursor up cursor left cursor right cursor down backlight down backlight up

The second column: PMT voltage down PMT voltage up Blankout down Blankout up Clear bins Dump screen to RS232 Acquisition off Acquisition on

'Blankout' suppresses that most left hand side (low energy) part of the spectrum, where often a lot of pulses are, that if left in would push the auto-scaling way down, making any real info difficult to see. In the same way (!) very energetic pulses that all would show up as max steps in the ADC, so cause a false peak all at the right, that value is discarded too, but the latest PC soft shows how many pulses were 'out of range', say co[s]mic rays, those are very very powerful events.

Then there is a green power LED (5 V present from converter) below that the power buttons Red (pressed for 10 seconds) = power off Black power on.

There is a 5 pole XLR connection to the scintillator probe on the right, and a 9 pole RS232 for connection to the PC.

Many [more] commands can be send via R232, status and control of the power converter, the acquisition PIC, and the LCD driver PIC are accessible (EEPROM is used to store settings). A MAX232 is located all the way on the left.

This is the power unit,

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the whole things runs for 10 hours from 2 NiMH 2500 mAh Duracells, with LCD brightness as in this picture, about half way (31 steps available including backlight off). The little grey wire disables a bias circuit that I added in the test setup for MOSFETS with a high Vgs on, this one did not need it, and it saves power disabling it (cut a resistor for that LED that is otherwise used to generate +2V). The mysterious current transformer is also clearly visible.. :-) All connections to the main processing board are via that 10 pin connector with flat cable, it has ground (2), 5V(20, RS232 RX TX, on button, and off button.

BTW the 'keyboard' scan is done in spare cycles of the acquisition PIC, complete with auto repeat, very nice for adjustment. The back will slide of sideways so the batteries can be accessed. In the empty space I have dreams of a NiMH charger, so you can plug it in too, found a nice Duracell paper on NiMH charging. So 3 PICs now, maybe a fourth PIC for charging? Side views:

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The RS232 screen dump, just like I did in 'scope_pic'. Will add a numeric dump too, could be useful. It can output binary too for use with the Linux spectrum display software I wrote.

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So this is version 2, BTW the software has been updated a lot :-)

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It was fun programming it all in the 18F14K22 PICs. Some more memory would have been nice, only about 255 bytes of RAM, I should patent the auto scaling in integer, works perfectly. A single chip with DIL package and 64 kB or MB RAM... same instructions set... When looking at the cost of the hardware, apart from the crystal in the probe.... I have beat the price of a decent Geiger counter and have a lot more features..

Reply to
Jan Panteltje
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Messed up the screen dump, here is all of it:

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Reply to
Jan Panteltje

Messed up the screen dump, here is all of it take 3):

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Reply to
Jan Panteltje

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