# Arduino Tutorial 50: How to Connect and Use the DHT11 Temperature and Humidity Sensor

The video develops the code to use this sensor step-by-step, but the code is included below for your convenience.

# Arduino Tutorial 49: How to Build a Simple Calculator with LCD Display

In this lesson we show you our solution to the assignment in Lesson 48 to build a simple calculator with an LCD Output. The video steps you through the project build step-by-step.

In the project, the following schematic is used.

If you need the kit we are using in this series of lessons, you can get it HERE.

And this is the code developed in the video.

# Arduino Tutorial 47: Binary and Hexadecimal Bit Flipper

In this lesson we explore how to create a Binary or Hexadecimal Bit Flipper. From our earlier lessons you see we can visually represent Hexadecimal or Binary numbers with a series of LED, with an on LED representing a “1” and an off LED representing a “0”. In programming and circuit applications, it is sometimes useful to “flip” or invert the bits. For an 8 bit number, one could do this in a program with 255 IF statements, but there is a simpler way. If you think about it, you can get the flippedByte by simple subtracting the byte from 0xFF, or 0b11111111. If you try some test cases, you can see that this will always work.

Simply stated, flippedByte=0xFF-Byte,

or if you prefer thinking in binary,

flippedByte=0b11111111-Byte

This is the circuit we are using to drive the 8 LED with the 74HX595 chip, and all this was explained in Tutorial 42.

This is the code which we developed in the video above.

In all these lessons we are using the Arduino Super Starter Kit, which you can pick up HERE.

# Arduino Tutorial 46: HOMEWORK- Create a Binary Bit Flipper with the 74HC595

The purpose of this lesson is to assign you homework. Your homework is to create a Bit Flipper. That is, for an 8 bit Binary or Hex number, invert the bits . . . “1” bits should become “0” and “0” bits should become “1”. For example,

if myByte=00001111

the flipped version of this would be

myByteFlipped=11110000

Similarly if myByte=00000001

myByteFlipped=11111110

You could do this with 255 if statements, but see if you can figure out a better way of doing it, and then demonstrate your results using the circuit we have been using in the last few lessons.

# Arduino Tutorial 44: Understanding Logical Shift Left and Logical Shift Right with the74HC595

In this lesson, we explore how to perform Logical Shift Left (LSL), and Logical Shift Right (LSR) functions on binary numbers, and we implement a circuit to perform these functions using an Arduino and a 74HC595 chip. We will demonstrate these functions on 8 bit binary numbers.

We start with the basic circuit and code which were developed in Lesson 42. In this lesson we are using parts from the Elegoo Arduino kit, which you can get  HERE.  We start with this circuit, which was explained in Lesson 42.

You can see that with this circuit, an 8 bit binary number can be visually displayed by illuminating the circuit LED. The goal of this lesson is to write code to perform LSL and LSR functions. The graphics below show conceptually how simple these functions are:

MSB stands for “Most Significant Bit” and LSB stands for “Least Significant Bit”.  You can see that the LSL function just moves each bit one to the left, and fills the empty LSB with a “0”.

The LSR funtion is just as simple as illustrated below.

Such shifts are often required when doing digital logic, so it is important to understand what the terms mean.

We can see that the LSL function can be performed by simply multiplying the binary number by 2. Similarly the LSR function can be performed by dividing the binary number by 2.

Code for LSL:

Code for LSR function: