Beginner level ProjectsTo start making these projects you don’t need any previous knowledge, I’ll explain all details clearly, provide many complementary info and give examples! Let’s have fun!
FansOne of most useful things that you would want to add into your helmet are refrigeration fans. This is a nice idea if you are going to wear it for hours and want to do it comfortably.
For this project we’ll need:
- 1 or 2 Fans
- Wire
- Battery
- Switch
- Welder & Tin
First thing we have to do is check what is the working voltage of the fan. Usually it is 12V. It means that we’ll need a 12V battery in order to use all potential of the fan. We’ll need really a 12V battery? If you want to use the 100% of the power of the fan, yes. But probably you will not want to have that amount of airflow inside your helmet, and more important, that amount of noise.
Anyway, let’s start the connections:
Each fan have 2 wires, usually red (+) and black (-) if you have other colors check the specs!
On/Off switches usually have 2 or 3 pins. 3 pin switches has: Common, Circuit 1, Circuit 2) pins. So, if you have a 3 pin switch you’ll use Common Pin and any other.
This is the diagram for 1 fan configuration:
This is the diagram for 2 fans configuration:
If we want to control the airflow of the fans and their power consumption, we can add a potentiometer between the battery and the switch.
A
potentiometer is just a component with a variable resistance that the user can modify, usually turning a dial.
Examples of potentiometers
A 10KΩ potentiometer would do the work in this case. In most potentiometers we will have to use the middle pin and one of the others, check the datasheet if in doubt.
The diagram would be the following:
This configuration will allow us to turn On/Off the fan(s) with the switch and regulate the airflow turning the potentiometer dial.
Lighting LEDsOn/Off LEDsWhile I was redacting the Sequence LEDs part, a question came to my mind: “What if someone want to set a lantern or a static light in its kit?”
So, in this part we’ll see how to do the connections to do a circuit with LEDs with a static (On/Off) behaviour.
We’ll need:
- Battery
- LEDs
- Resistors
- Switch
- Wires
- Welder & Tin
First of all, we have to know the maximum current that our LEDs allow. In my case, I have checked the datasheet and see that the Imax=20mA. Next thing is to chose our power source. For this project I’ll use a common 9V battery.
Once we know the power source’s voltage (V) and the maximum current (I) allowed by the LED the only parameter that lefts is the resistance ( R). If we don’t set a resistance in our circuit, LEDs will break due to an excessive current. Now it’s maths time
Applying Ohm’s Law:
R=V/I
In my case R=9V/0.02A=450Ω
This means that I’ll have to set a resistor of 450Ω (more or less) before the LED in order to protect it. This would be the wiring diagram of my circuit:
As you can see, there is only 1 LED in my circuit. Of course we can connect more. We can do a Series connection or a Parallel connection.
This would be a 3 LEDs in a series connection diagram:
And this one would be the parallel connection one:
Personally, I recommend to wire multiple LEDs in series. Series connection are simpler and consumes less than parallel ones. Its disadvantage is that, if one LED breaks, every other will turn off until the broken one is replaced. If you are interested in the differences between connecting LEDs in series or parallel check this nice guide -
LEDs for beginners!
Secuence LEDsThis will be the first project that will include an Arduino board, yay!
In this project we’ll learn how to light a LED and we’ll create a sequence for multiple LEDs.
For this project we’ll need:
- Arduino board
- Battery
- LEDs
- Resistors
- Protoboard
- Welder & Tin
In the diagrams of this project I’ll be using a protoboard. I suggest you to do the same in order to learn and, after all is working fine, you can solder it all in a pcb.
First, we’ll calculate the value of the resistor that we’ll need to put in the circuit in order to protect the LED (we already saw it in the previous project). Note that the voltage given by the Arduino pins are 5V, that’s why in most case we’ll need a 220Ω resistor.
After that, we’ll connect the components as following:
Now is coding time! Don’t you worry if you have never seen code before. I’ll try my best to explain it! And… Copy & Paste is always a valid option!
This is be the code that we’ll upload in our Arduino board to blink our LED (this code is a modification of the Blink example provided by arduino):
Arduino Code: Sequence LEDs #1 It works! Is not magic! Don't be shy and try to modify the delay values! If you set them higher, you have seen that the LED remains more time in that state, if you set it lower you have observed that the LED remains less time in that state.
Let's move to the Fade effect! Maybe we don’t want to only turn on/off the LED, sometimes we would want it to fade in and fade out. Using the same connections we did in the previous example, we’ll upload this code (Fade example provided by Arduino):
Arduino Code: Sequence LEDs #2 Once again try to modify the delay, brightness and fadeAmount values!
Ready to make a sequence? Let’s go! We’ll need more LEDs (I’ll use 3 LEDs in this project) and the same amount of resistors.
This is the diagram I followed:
For this project, the sequence I want to program is the next one:
R B Y (2 seconds)
- B - (1 second)
R - Y (1.5 seconds)
- - Y (0.75 seconds)
R - - (1 second)
So, for that sequence this would be the code:
Arduino Code: Sequence LEDs #3 Do you feel confident? Try to make a different sequence! Add more LEDs too!
Note: Digital pins 0 & 1 are reserved for system communications, do not use them!
Moving a servomotorDetails make the difference, and what could be better than a moving part in your kit?
Imagine your range-finder moving to the aim position and then going back to the straight position, sounds good? Let’s see how to do it!
A servomotor is a special kind of motor that allows to control its position and maintain it. Common servomotors can turn up to 170º-180º, but there are models with a larger range. In this project we’ll see how to set up a servo using Arduino. The loop sequence will be the following:
Turn from 0º to 90º
Wait 2 seconds
Turn from 90º to 140º
Wait 5 seconds
Turn from 140º to 0º
Wait 3 seconds
This is the wiring diagram:
Usually the Black wire is used to indicate the ground, Red wires the power and Yellow wires the signals. If your servo has different colors or you are not sure about the connections, check the datasheet.
Note that the signal wire is connected to the Arduino’s pin
~3. This is a special type of digital pin called PWM. The Arduino UNO board has six PWM pins (3, 5, 6, 9, 10, 11). We can easily distinguish them because they are preceded with the
~ symbol.
Common digital pins can only read/write HIGH and LOW signals. For example, if we connect a LED to a digital pin we will only be able to set it ON/OFF, but we won’t be able to change its intensity.
PWM pins have 256 levels (0-255) of power between the LOW and HIGH limits. Using the previous example, if we connect a LED to a PWM Digital pin we will be able to light it at maximum intensity (255), switch it off (0) and control its intensity (f.e. 127 for medium intensity).
And this will be the code:
Arduino Code: Servomotor #1Easy, right? Well, this is not the best way to move a servo, but it’s the easiest way and works. Now we’ll see the proper way to do it, doing this we’ll be able to control the rotation speed.
We’ll use the same connections as the previous example, and this will be the code (based on Arduino’s example Sweep):
Arduino Code: Servomotor #2That’s it! Have you seen the difference? Great!
Adding a button to your projectsI think that, in most cases, we would want the electronics to do something on demand. For example, we would want to move the range-finder to the aim position when we push a button and to turn it back when we release that button.
We will differentiate two kind of buttons, according to its mechanism:
- Switch when pressed: Change state on a button press. Remain there until another button press.
- Switch until released: Change state on a button press. Change back when the button is released.
The buttons that we’ll use in this projects have 4 pins, and these are the connections:
As we can see, in the Released State the pins 1 & 2 are connected with each other (red line) and the same happens with pins 3 & 4 (yellow line). When we press the button, the connections change to connect the pins 1 & 4 together (yellow line) and the same occurs with the pins 2 & 3 (red line).
So, as now we know about the behaviour of the buttons lets see how to include them into our circuits!
Let’s start with an easy example, an On/Off LED controlled by a button. In this example we’ll use a
switch until released button and the LED will be turned On while the button is pressed and will be switched off when the button is released.
This would be the wiring diagram:
We have used the breadboard’s two bottom lines to do the +5V connection (+) and the ground connection (-). As the picture shows, the LED is connected to the Arduino’s digital pin 2 in the same way we saw in the Lighting a LED project.
Let’s see how we have connected the button. As we saw at
Protoboards explanation, each protoboard row connections are splitted in half, so we can connect the button in the middle of this separation (note that none button pin is connected to another). And there is a new concept called “pull-down resistor”. This resistor is the 10KΩ we connected between the button pin 4 and the ground. Let’s say that this resistor will be necessary every time we’ll use a button to avoid wrong reads. We are not going to go deeper in this concept, but if you are curious about what this resistor does I recommend you to read
this Sparkfun article.
So, what this circuit does? Simple, if the button is released it will connect the ground to the Arduino’s digital pin 6 (LOW signal). If the button is pressed it will connect the +5V to Arduino’s digital pin 6 (HIGH signal).
Let’s see the code:
Arduino Code: Button #1Easy, right? What would happen in the previous example if, instead of that button, we have used a button with a
switch when pressed mechanism?
Let’s compare the behaviour:
| State of the button | Switch until released | Switch when pressed |
| Released | LED OFF | LED OFF |
| Pressed | LED ON | LED ON |
| Released | LED OFF | LED ON |
| Pressed | LED ON | LED OFF |
| Released | LED OFF | LED OFF |
But… could a
Switch until released button behave as a
Switch when pressed one? We can do something similar by coding it! If you are brave enough follow me! (maybe this have to be in the medium level projects… but I’m motivated! If you do not understand it feel free to scroll to the next project!)
We’ll use the same wiring as the previous example, only changing the code:
Arduino Code: Button #2If this was not too hard for you, you could try to add another LED and add another LEDstate to make this sequence!
Click on button -> LED 1 On
Click on button -> LED1&2 On
Click on button -> Both LEDs Off
We did this project using LEDs, but feel free to add button into any kind of project you want!
Lighting a 7 Segments DisplayFirst of all, what is a 7 segment display?
Well, it is a component composed by 7 LEDs (or 8 if there is the decimal point) disposed making a “8” or “B” form. These LEDs can be lighted separately making possible to display numbers, letters or symbols.
The 8 LEDs displays usually have 10 pins. But... If 8 LEDs make 16 pins (2 pins each)… why the display only has 10? In order to reduce the number of pins and the number of connections, all pins (positive or negative) are connected together. Let’s see their configuration:
Attending to the polarity of the pin they are connected to each other we can distinguish 2 types of displays: Common Cathode (positive pins connected) and Common Anode (negative pins connected).
If we use a Common Cathode display with our Arduino we would simply have to connect the display’s GND pins to the Arduino’s GND pins and each other display’ pin to a Digital pin of the Arduino.
If we use a Common Anode display, we would have to connect the display’s VCC pin to the Arduino’s VCC pin and find a way to connect the cathode of the display that we would like to light to the ground… As we’ll see at the Lighting Multiple 7 Segments project this can be done using transistors, but not now. For this project we’ll use a Common Cathode display. Check your datasheet to be sure!
Let’s see now the position of the LEDs. As you can see, each LED inside the display has a letter that identify it. This will be important when wiring the display, I recommend doing it in order to avoid confusions.
For example, the number 1 would be represented lighting the segments “a” and “b”, the number 2 with the “a”, “b”, “d”, “e” and “g” segments.
Got it? Then let’s see the wiring diagram:
For the first code example we’ll light it raw. We’ll display “MERCS”. Note that there are limitations on what we can display. For example the letter “M” will see more like an inverted “U” than like a propper M.
The code would be the following:
Arduino Code: 7 SegmentEasy right? It’s like using 8 LEDs!
There are other ways to display things, but as they involve the use of libraries, we’ll see it in the Medium Level Projects.
Aaaaand that's all! If you enjoyed the Begginer Level Projects and you want to dig a little big more into the electronics world I dare you to start with the Medium Level Projects!
