Low power Geiger counter with MSP430G2553 (Last updated: May 07, 2015)

[DeepBlueSky 8]

Last updated: May 07, 2015

May 07: added SBM-20 background CPM value vs 1kg potassium salt and python code to log the data.

April 26: added deadtime image.

April 23: updated to 75

[cubeberg 540]

@@DeepBlueSky - **edit -that's what I get for not reading your code.  Looks like there might be an issue with sprintf - https://github.com/energia/Energia/issues/249

Maybe try switching to unsigned int which holds up to ~65k?

[DeepBlueSky 8]

Changing to "unsigned int counts;" doesn't help.

[enl 227]

Use long int (or long unsigned) and use `ld'  (lowercase ell d )instead of `d' in the format string for sprintf. `d' is standart int. `ld' is long int.

 

 

The only info sprintf has about the type is from the format string, so if you spec standard int, whatever the param is, even if it is a long, will be interpreted as a standard int.

[DeepBlueSky 8]

Thanks, this helped to solve first of the two problems

[spirilis 1,265]

Isn't there a "%u" option to tell sprintf/printf/etc. to interpret it as unsigned?

[DeepBlueSky 8]

Isn't there a "%u" option to tell sprintf/printf/etc. to interpret it as unsigned?

If I try %u it only goes up to 2^16, if I use %ld it goes up to 10 digits or so, so much better.

[spirilis 1,265]

If I try %u it only goes up to 2^16, if I use %ld it goes up to 10 digits or so, so much better.

Ah right, agreed, didn't fully read the first post

 

I think %lu may work too for going up to ~4 billion with unsigned long's.

[DeepBlueSky 8]

Ah right, agreed, didn't fully read the first post

 

I think %lu may work too for going up to ~4 billion with unsigned long's.

Thanks, you are right, it goes up to 2^32 ? 1, whereas ld doesn't.

void loop() {
  counts=4294967296-1;
  sprintf(string,"%ld",counts);
  myScreen.text(0,0,string);
  sprintf(string,"%lu",counts);
  myScreen.text(0,1,string);
  delay(100000);
}

[enl 227]

don' bother float.... If the value won't overflow (less than about 650*10^6 decimal), mult by 3 than divide by 100. The mult by three can be done as `(i<<1)+i'. This will give an int value truncated.

 

 

You can avoid the div by 100 completely. After the sprintf, insert a decimal point before the last two digits. This requires that the value is >= 100 decimal, or there won't BE anything before the last two digits. This can be handled by forcing leading zeroes for 3 dig if value is <100 (using a condition and two sprintf's... one for each case)

[igor 163]

 

Hi all,

 

2. Problem: how to convert an number into a float point number, e.g. if I want to multiply counts variable by 0.03 and display it?

 

 

I take it the built-in sprintf doesn't handle floats?

If want to do it without using floats - could do something like:

unsigned long long count3 = 3 * counts;
sprintf(string,"%lu", (unsigned long)(count3/100) );
myScreen.text(0,1,string);
add code to print the decimal point in the right position
sprintf(string,"%u", (unsigned) (count3 % 100));
print this in the appropriate location

That is just the skeleton - would have to fill in the printing code (and conditionals to handle 0 fractional part, etc.)

[DeepBlueSky 8]

Updated first post with proper function now and added images, enjoy

[paodaf 2]

The compensation function works fine Thank you for sharing it.

407387 CPM its non compensated value triggered by several Am-241 pieces placed on SBT-11 mica window, see the photos. The software displays compensated dose rate of 8.00mSv/h with 190uS dead time and 0.0057 conversion fator.

[DeepBlueSky 8]

The compensation function works fine Thank you for sharing it.

407387 CPM its non compensated value triggered by several Am-241 pieces placed on SBT-11 mica window, see the photos. The software displays compensated dose rate of 8.00mSv/h with 190uS dead time and 0.0057 conversion fator.

 

Thanks

I'm not sure but I think compensating 407387 CPM with 190