Wave generator is one of the most needed tools in our electronics labs, you can buy a fully functional ready made one or make a simple one using your Arduino.
Joekutz over Hackaday.io created a simple wave generator using Arduino powered from 9V battery and produces amplified and non amplified signals. This generator uses the 8-bit resistor ladder, aka R2R, DAC with 0.0195V step, knowing that Vout of R2R DAC is Vout = Vref × VAL / 2^N Where N = 8 (hence 2^8 = 256) and Vref = 5.0 V.
Joekutz used the “Arduino Waveform Generator” instructable, but he added to the original project design a LCD display, a speaker to hear the generated wave and edited the way how user sets the waveform and frequency.
Joekutz decided to hack a cheap calculator LCD and to use it in his project, he found out how to emulate a press of “CE, +, = and 1” Keys using Arduino, so he can display any number using this hack, for example displaying 123 on the LCD means the following sequence: 111 + 11 + 1.
He created an Arduino library for his hack. You can see the below video from Joekutz explaining LCD hack:
In the below video Joekutz demonstrates the project:
You can download the Arduino Library and sketch files from the project page on Hackaday.