running with a scope probe on the same line going to the maple.

paired transistor has it's free leg tied to the middle leg.

noise looks like usual on scope, about 0-2v, very rounded, characteristic time
of a pulse around 500ns total.

used entropy_hex.cpp, then ran:

    cat /dev/ttyACM0 | pv > some_bits.hex

got 200-300B/s

==============================================================================
chars: 2262
        0: 152  0.067197        1.075155
        1: 141  0.062334        0.997347
        2: 165  0.072944        1.167109
        3: 145  0.064103        1.025641
        4: 159  0.070292        1.124668
        5: 141  0.062334        0.997347
        6: 158  0.069850        1.117595
        7: 100  0.044209        0.707339
        8: 152  0.067197        1.075155
        9: 139  0.061450        0.983201
        A: 147  0.064987        1.039788
        B: 133  0.058798        0.940760
        C: 146  0.064545        1.032714
        D: 123  0.054377        0.870027
        E: 155  0.068523        1.096375
        F: 106  0.046861        0.749779
bits: 9048
        zeros: 4722     0.521883
        ones: 4326      0.478117

==============================================================================
$ cat partial.bin | rngtest 
rngtest 2-unofficial-mt.14
Copyright (c) 2004 by Henrique de Moraes Holschuh
This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

rngtest: starting FIPS tests...
rngtest: entropy source exhausted!
rngtest: bits received from input: 8333528
rngtest: FIPS 140-2 successes: 121
rngtest: FIPS 140-2 failures: 295
rngtest: FIPS 140-2(2001-10-10) Monobit: 226
rngtest: FIPS 140-2(2001-10-10) Poker: 254
rngtest: FIPS 140-2(2001-10-10) Runs: 93
rngtest: FIPS 140-2(2001-10-10) Long run: 1
rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
rngtest: input channel speed: (min=1.330; avg=7.733; max=18.626)Gibits/s
rngtest: FIPS tests speed: (min=36.261; avg=83.809; max=104.799)Mibits/s
rngtest: Program run time: 97333 microseconds
bnewbold@ziggy:~/code/entropy/test_20121121$ cat partial.
partial.bin        partial.hex        partial.white.bin  


==============================================================================
$ cat partial.bin | ent
Entropy = 7.991205 bits per byte.

Optimum compression would reduce the size
of this 1041691 byte file by 0 percent.

Chi square distribution for 1041691 samples is 12677.89, and randomly
would exceed this value 0.01 percent of the times.

Arithmetic mean value of data bytes is 129.3382 (127.5 = random).
Monte Carlo value for Pi is 3.092728163 (error 1.56 percent).
Serial correlation coefficient is 0.005857 (totally uncorrelated = 0.0).


==============================================================================
$ cat partial.white.bin | rngtest
rngtest 2-unofficial-mt.14
Copyright (c) 2004 by Henrique de Moraes Holschuh
This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

rngtest: starting FIPS tests...
rngtest: entropy source exhausted!
rngtest: bits received from input: 2071600
rngtest: FIPS 140-2 successes: 75
rngtest: FIPS 140-2 failures: 28
rngtest: FIPS 140-2(2001-10-10) Monobit: 28
rngtest: FIPS 140-2(2001-10-10) Poker: 4
rngtest: FIPS 140-2(2001-10-10) Runs: 1
rngtest: FIPS 140-2(2001-10-10) Long run: 0
rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
rngtest: input channel speed: (min=1.164; avg=5.958; max=18.626)Gibits/s
rngtest: FIPS tests speed: (min=34.933; avg=64.741; max=104.799)Mibits/s
rngtest: Program run time: 31552 microseconds

==============================================================================
$ cat partial.white.bin | ent
Entropy = 7.996434 bits per byte.

Optimum compression would reduce the size
of this 258950 byte file by 0 percent.

Chi square distribution for 258950 samples is 1285.33, and randomly
would exceed this value 0.01 percent of the times.

Arithmetic mean value of data bytes is 130.3190 (127.5 = random).
Monte Carlo value for Pi is 3.074841281 (error 2.12 percent).
Serial correlation coefficient is 0.002130 (totally uncorrelated = 0.0).