Analog, Digital & PWM Signals for Arduino & Raspberry Pi- Electronics Crash Course #8
Channel: Saral Tayal
Date: 2019-02-01

Enroll in the full version of 'Electronics Crash Course' here: https://www.udemy.com/electronics-in-a-nutshell/?couponCode=TINKERSPARK

My FREE introduction to robotics course- https://tinkerspark.teachable.com
Facebook- https://www.facebook.com/tinkerspark1/
Twitter- https://twitter.com/saraltayal
Full Article- https://tinkerspark.org/digitalanalog/
My website- https://tinkerspark.org

Learn the differences between Digital, PWM, and Analog signals for Arduino and Raspberry Pi


All electronics function on analog or digital signals, master them today in this tutorial

All signals fall under the analog or digital subset when we talk about electronics. A great example is video signals; HDMI is digital while composite/rca is analog. Both signals are similar in the sense that they carry information using voltages but they differ in how they carry the information. Lets first talk about analog signals. Analog signals were mainstream in the 1900s when most electronics were considered analog electronics and relied heavily on circuit design rather than micro controllers and microprocessors. These signals are smooth voltage curves that can be represented by voltage graphs like these. When fed into a microcontroller, these voltage values are typically broken into a 1024 value range (0-1023). Therefore by manipulating the voltage levels, we can change the reading our micro-controller device reads. Examples of analog devices are potentiometers, audio signals, composite video signals FIND MORE

Digital signals have gained popularity in electronic devices ever since computing became mainstream with micro controllers and microprocessors. the word digital stems from the term digit: distinct integers. Unlike analog which are continuous  functions, digital signals use discrete numbers for calculations. Think slider ruler vs abacus. 

Computers represent digital values with binary which is a base 2 number systemDigital can be represented by a voltage range, just like analog values. one way to think of this is that if 0v was a 0 and 3v was a 1023 for analog, a 0v on a digital signal would be 0 and 3v signal would be 1. This is much similar in theory compared to analog values but digital signals by design can carry much less information due to having only 2 states vs 1023 in analog signals. To fix this they use clever timing techniques such as PWM to emulate analog signals and carry high amounts of data. 

(DRAWING) PWM works by injecting tiny variable gaps/0 signals into the digital data stream to effectively rapidly turn on and off the signal. This way when the pwm signal reaches the electronics item, it approximates an analog voltage signal since its flipping so fast. Servos are a very common device that uses PWM signal to function. Let's do a quick demo to understand how PWM signals can emulate analog signals.(DEMO)

SPI and I2C signals work in similar ways by standardizing the size of gaps between digital data and what that represents

Analog to digital converters are another device that allows us to convert analog to digital audio signals. These are often found built into devices like the raspberry pi or arduino