Very first notes
SD file system tools on Mac OS
usefull info on following link:
https://www.raspberrypi.org/documentation/installation/installing-images/mac.md
http://www.theinstructional.com/guides/disk-management-from-the-command-line-part-1
diskutil list
diskutil info /dev/disk1
diskutil unmount /dev/disk1s1
unmount single partition
diskutil eject /dev/disk1
copy all disk to raw partition
sudo dd bs=1m if=image.img of=/dev/rdisk<disk# from diskutil>
FAT-16 format
newfs_msdos -F 16 (path to SD Card device)/(SD Card device number)
e.g. newfs_msdos -F 16 /dev/disk5s1
diskutil partitionDisk /Volumes/WII 1 MBRFormat "MS-DOS FAT16" "WII" 1000M
Partition a disk with three partitions
diskutil partitionDisk disk3 3 HFSX Name1 10G JHFS+ Name2 10G MS-DOS NAME3 10G
l'ultima partizione viene estesa fino infondo quindi è necessario darne 1 fat16 e la seconda a piacere
altrimenti va in errore:
diskutil partitionDisk disk1 2 MBRFormat "MS-DOS FAT16" "WII" 1000M MS-DOS NAME3 1G
or
diskutil partitionDisk /dev/disk1 MBR "MS-DOS FAT16" "WII" 1000M MS-DOS NAME3 1G
diskutil unmountDisk /dev/disk<disk# from diskutil>
sudo diskutil unmount /dev/disk3s1
Take care to info in this blog and related
http://davidegironi.blogspot.com/2014/01/cheap-co2-meter-using-mq135-sensor-with.html#.W6fCIy2B3MW
and
https://automeris.io/WebPlotDigitizer/
AD converter precision
Lot of problem with AD voltage reference internal o r external too.
Solution
1 - using zenner diode 3 Volt (ITT ZPD 3) alone completely unusable
2 - using zenner and current source (PNP BC557)
3 - Using precision voltage reference TL431 .. the easiest one .. waiting from eBay ...