Arduino Digital Multimeter/Oscilloscope Free

This Digital Multimeter help you to test: volts, Ohms, temperature, the light (lx),
frequency, amplitude, and see wave form of the sound frequency.
It's easy to build, you just need some arduino, bluetooth module, temperature sensor and some resistances, and for Oscilloscope:some old headphones with 4 pins and capacitor from 0.1mF to 1mF.Video tutorial How to use oscilloscope:
https://youtu.be/ZwNe8yEjjxo
.For build the circuit follow this
LINK FOR DOWNLOADSCHEMATIC:https://drive.google.com/open?id=1njr87NnkufkngM6CPMGtq6pBCRm89kvJ
LINK FOR DOWNLOAD ARDUINO SKETCH HERE:
https://drive.google.com/open?id=18b1JUFug3h3LFuA8wlHuca0tmpbk-Hbp