First of all, thank you Jeff for the great kit you desiged. I got one from adafruit and it really works well!! I have a radiometric control here (Sr-90) and would like to dig a little bit deeper. For this I would like to have a proper readout (beside the clicks).
Now I found the "geigerbot" app in this threat, and its a great app. It works well with the input over the internal ipad mic but to exclude unwanted noise it might be VERY useful to hook it up to the audio-jack of the ipad directly.
I found in the documentation a audio-hookup scematic here (partly japanese) : http://www.higuchi.com/item/629
As far as I understand the red circled part is of particular intrest and would be easy to make myself. But before I blow my ipad I would like to have some opinions on this...
The guys from geigerbot say about the "optional line input" - found here: https://sites.google.com/site/geigerbot/docs
(in order the keep the iphone/pad alive...)
"The points of this schematic are:
- Divide the output voltage (in this case, about 9Vp-p) down to about 0.1V
- Do not decouple the output and iPhone mic input. Let the DC bias on iPhone mic input drop"
Could you calculate wich resistors/capacitors are best to use? Can I use the pulse-port of the Counter, and which is gnd?
Would be great I you find a few minutes...
Markus from Berlin/Germany.
P.S. Making the Geiger Counter connectable to an iphone/ipad could raise selling numbers...