Let Yun Measure/Datalog DCV/ACV/DCA/ACA/R/CAP/Freq/Temperature

 lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 058f:6254 Alcor Micro Corp. USB Hub
Bus 001 Device 003: ID 0424:2507 Standard Microsystems Corp. hub
Bus 001 Device 004: ID 058f:6366 Alcor Micro Corp. Multi Flash Reader
Bus 001 Device 006: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port
opkg update
opkg install kmod-usb-serial kmod-usb-serial-pl2303

http://forum.arduino.cc/index.php?topic=211213.msg1549909#msg1549909

opkg update
opkg install python-openssl #adds ssl support to python
opkg install distribute #it contains the easy_install command line tool (this can take some time)
easy_install pip #installs pip  (this can take some time)
pip install  pyserial

http://forum.arduino.cc/index.php?topic=244536.msg1751021#msg1751021

cd /usr/lib/python2.7

wget https://raw.githubusercontent.com/Xuth/tp4000_dmm/master/tp4000zc.py
nano /mnt/sda1/read.py
# load the module
import tp4000zc

# the port that we're going to use.  This can be a number or device name.
# on linux or posix systems this will look like /dev/tty2 or /dev/ttyUSB0
# on windows this will look something like COM3
port = '/dev/ttyUSB0'

# get an instance of the class
dmm = tp4000zc.Dmm(port)

# read a value
val = dmm.read()

print val.text       # print the text representation of the value
                     # something like: -4.9 millivolts DC
print val.numericVal # and the numeric value
                     # ie: -0.0048
# recycle the serial port
dmm.close()
python /mnt/sda1/read.py
-50.2 millivolts DC
-0.0502

DCV: 0-4-40-400V±0.5%-1000V±0.8%
ACV: 0-4-40-400V±1.2%-750V±1.5%
DCA: 0-400mA±1.2%-10A±2.0%
ACA: 0-400mA±1.5%-10A±3.0%
R: 0-400-4k-40k-400k-4M±1.2%-40M±3.0%
CAP: 0-4n-400nf±4.0%
Freq: 0-40kHz±3.0%
Audible continuity: <30ohm
Transistor: hFE: 0-1000
Diode test: 25uA,3.0V
Temperature: 0C/750C Resolution 0.1C

Sample Datalog: