This is a crazy idea of mine now I will explain to you :

Have you ever wondered to leave a message in the sky, whether the word or sentence is made with smoke signals left behind by an airplane or with drones flying in synchrony?

I wondered.

So I figured out how to make something such that, with minimum cost and the solution was using cheap 1€ mini-hot-air-balloon from the shop behind the corner

This is what happened

## Step 1: Get the Things You Need

1 Hot-air-balloon chinese lantern

1 Arduino UNO

1 Mosfet transistor IRL1104

1 Mega Ohm resistor

1 Kilo Ohm resistor

Scotch tape

Jumper Wires

Nichrome Wire (I take a little piece from an old hairdryer)

## Step 2: Circuit

This is the circuit to heat the nichrome wire in order to make hot-air-balloons fly, once it's ready.

The circuit is simple but you must pay attention

The important thing is to use a power supply that provides the right amount of Ampere

Nichrome wire has a very low resistance when it's not heated, so make sure you can give at least 3-4 Ampere,

I used for this an old power supply but you can use whatever you want

ATTENTION!

The nichrome wire heats a lot, be careful in your experiments

You can use a voltage in the range of 7-15 volts.

## Step 3: Make the Launch Station

It's time to make the launch station.

A piece of wood or something that is heavy enough to counterbalance the force of the flying lantern will be ok

I used scotch tape in order to attach the jumper wires and the nichrome wire to the wood,

I attached also piece of scotch tape around the nichrome wire an then at the base of the balloon so, when it is heated, melts the plastic and let the hot-air-balloon fly in the blue sky.

Place the balloon in the right place (see photo showing my solution: a Brand New Carton with two holes)

(The reason of the breadboard full of wires in the photo is that I tried with more than one hot-air-balloon in order to make a bigger launch stations, with more balloons synchronized)

## Step 4: Code for Arduino

The code for arduino is simple, in fact it is enough to give tension to the GATE of the MOSFET from a digital pin (the 5th in the case you have followed my diagram in the first step)

During my experiments, I noticed that heating the nichrome wire for 4 seconds it's enough to melt the plastic

This will just work fine

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static int nichro1=5;

void setup() {

pinMode(nichro1, OUTPUT);

digitalWrite(nichro1, LOW);

}

void loop() {

delay(5000);

digitalWrite(nichro1, HIGH);

delay(4000); %wait 4 seconds in order to melt the plastic

digitalWrite(nichro1, LOW);

}

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## Step 5: Make the Balloon Fly

Just make it work!

Place the launch station in a safe place, far from other houses or trees but most importantly in an open air space. You don't want the balloon to burn any house

Make the correct wirings, place the power supply, start the lantern with a light or a match and when it's hot enough to stand alone, power the arduino so he can do the synchronized thing.

ENJOY!
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OK, I know that in the case you use only ONE balloon no word or message or sentence can possibly be made

You got reason, but don't waste your energy in criticism and try to make a launch station with TWO, THREE or even FOUR (!) balloons

I, me and my self tried.