Calculator

 

I had promised to show what you can do with an arduino, leds and few buttons. I had said you can do quite a lot. 

Here is the first project in the series of showing the power of a turing machine. 

I built a calculator that can add numbers. You can give one number after another and it will keep adding it. 

But you need to read the result in binary and convert it to the regular numbers we are familiar with because leds show results(numbers) in binary. 

The left button is for incrementing the number from 1, 2, 3 .... . The right button is to add that number to the accumulator. The accumulator stats with 0. Accumulator stores the result of all additions so far. 

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Knock Detector

 

Using a spy(small) microphone and an opamp to boost the small signal from the microphone, i built a knock sensor following a tutorial from youtube. 

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Preparing the EE toolkit

 

I have been away for a few days buying items to prepare my toolkit. 

Many times when you sit down to start a project and you realize you are missing a required item. So it is good i think to prepare in advance by buying or collecting all things you might need for the electronics projects. 

I went to the electronics shop nearby Himalayan solutions and bought the items i thought are the most common things for any electronics projects. 

Here is my workshop. I have grouped different electronics components in plastic bags to make it easier to find when needed. 

Shown here are Multimeter i bought from Himalayan solution. Battery holders i took out from toys at home. From left, some jumper wires, slide switch, motor, dc jack. 

Shown here are breadboard, LCD module (bought recently from Himalayan Solutions),  Arduino Uno.

From top left, 9 volt battery, jumper wires, 9v battery cap, 1.5 volt batteries, diodes, photo resistors, servo, speakers or piezo buzzers, piezo electric sensor, microphones. 

From top left, opamps, transistors, 0.1 uf capacitors, capacitors pack, resistors pack, potentiometer, reset switches, RGB leds, IR leds (mistakenly bought thinking normal leds), leds.

Although it would be nice to complete the EE toolkit with an oscilloscoe, power supply, soldering machine and function generator I think for now i can start some projects with the help of these. 

Maybe they are for future list. 

Let's start to build something. 

Project # 9

 

We had a light bulb in home that would turn on when clapped with hands. This was long non functional however. 

Yesterday I thought of seeing what was inside. 

There were few useful electronic components I could use for the projects. 

It had a microphone and a photoresistor. I understood how it worked. The light would only turn on during the night when the room was dark. The microphone was used to detect the clap and the photo resistor was used to detect the darkness of the room. 

Here is the demonstration of how a photoresistor works. 

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Project # 8

 

I have been digging through the old toys at home to extract electrical components that I can use in the projects. 

Here a teddy donated his organs for the purpose of engineering. Thank you friend.

The doll would light up and play a melody when tapped gently. 

It used an electrical component called a piezo electric sensor to detect movements, taps, vibrations. 

Here is a demonstration of how a piezo electric sensor works. 

    

In this project, I have used a piezo sensor to light up an led. When the sensor is pressed or dropped the led lights up.

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Project # 7

 

After the successful operation of the electric motor, spent all day yesterday creating this robo car. This doesn't have arduino yet. 

Robo Test Run #1

Robo Test Run #2

Robo Test Run #3

Project # 6

 

Yesterday i worked all day on making a motor run. It turns out it isn't as simple as it sounds. 

The Arduino pins it turns out cannot generate the amount of current the motor requires. 

I had to use a transistor to drive the motor. The online tutorials were using NPN transistor which is easier, i had to figure out how to do it using a PNP transistor. It had been a long time since i took electronics course.

Here is the victory video.

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Explanation

Project # 5

 

With the piezo speaker extracted from the toy last week, this week i worked on a circuit to play a melody. Figuring out the melody notes took some time. 

Here is the demonstration of the bhajan Om Jaya Jagadish Hare. 

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Taking out useful parts

My childhood toys donated their useful parts to me for the projects. Thank you!!  I will not let your sacrifice go in vain. 

Toy Plane

Useful Parts

Motor with gears, Piezo Speaker, Wheels, Slide Switch, Transistor, Capacitor

Toy Robot

Useful Parts

Battery Holder, Transistor, Capacitor, Wheels

Damaged Router

Useful Parts

Push button, Power jack pin

Project # 4

What is the least you need to solve any problems? If there is a way to do it a computer which is a turing machine can do it.

So what do you need at the least?

You need an arduino, leds (some way to display the output) and switches (some way to give in input). With these 3 you can solve almost any interesting problem.

In the future projects i will try to demonstrate what i mean by that.

Last week when i went to the electronics shop i bought arduino, leds, breadboard, wires. But for some reason i didnt get a button or a switch maybe because they ran out of it. Looking around i noticed this old toy plane sitting in the shelf and saw what i needed. 

I took out the sliding switch from it and used it to demonstrate how to take in input from the switch. 

Here is the demonstration of input using slide switch. 

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Project # 3

 

What if a single led can generate multiple colors? What if a led can generate any color? Isn't that amazing :)

Here is the demonstration of a RGB led in action.

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Project # 2

 

We can use potentiometer to take in input from the real world. By turning the knob we can take in values for example 1-1024. 

Here is the demonstration of controlling a blinking led using a turning knob called potentiometer.

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Project # 1

 

You can count using leds. When you can count, you can calculate. When you can calculate you can do almost anything.

We count 1, 2, 3, 4, 5, ..... but if we represent the numbers slightly differently like this 1, 10, 11, 100, 101.. then we can use leds to represent them.

Here is the demonstration of  a counting circuit using leds.

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Return to the Embedded World

 

As a kid, i grew up watching these two cartoons. 

                                                                Click to enjoy the intros.

                                                    Warning: Chills may run through the spine.

In my view these two cartoons exemplify wonderfully the embedded world.

Here is how I view embedded systems.

The computers we are used to, run programs which take inputs usually through mouse and keyboard. The output of the program is seen usually through a monitor.

In the embedded world the analogous to computers are microcontrollers which run programs usually written in C language. They take inputs from various sensors such as buttons, accelerometers, flex sensors, potentiometers etc and the outputs are usually displayed through leds, lcd screens or they drive, motors, servos etc.

In other words in the normal computer world computer does things inside the monitor. In the embedded world computer does actual things in the world such as you see in the cartoons above eg. fly a plane (turbo jet), send exoskeletal weapons from the space  etc. 

Since i studied computer engineering in college there has been a long gap. I will slowly build from small. Before that i need to refresh some concepts. Let's see where we get.