Hi! This is AnTiProcrastination. We are from University of Michigan -- Shanghai Jiao Tong University Joint Institute (see Logo. in Figure 1) located in Min Hang District of Shanghai (Figure 2; cited from www.ngeschool.org). AnTiProcrastination is formed as a team in the course "Introduction to Engineering", and will finish two engineering projects during the course.
We wrote an instructable about Remote-controlled hovercraft last time (https://www.instructables.com/id/Remote-controlled-...). This time, we will introduce how to make a projection-making advertising blimp.
The idea of the advertising blimp comes from our intention have a new way of advertising. There already exist means of advertising, but they are either expensive (e.g. TV commercials) or boring(e.g. pamphlets). What we want to do, is to develop a system that is affordable, yet attractive. Then, projection on the ground might be a good way of advertising, since it can be easily made, and is interesting.
Our blimp has four main functions. Namely, It can project on the ground. It is able to show multiple ads. It can fly around and interact with people, and we’ve designed an app based on Android system to control it manually. It also has the function of auto-control.
Now let's see how we have constructed our blimp.
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Step 1: Design the Blimp
The first thing to do is to design the blimp. Designing can be quite important because a clear and explicit design works as a guide when you start constructing the system.
Based on the function that we want to achieve, our blimp mainly consists of three parts: projection system, the blimp itself with the propulsion system and the controlling system with sensors.
The projection system, the major part, includes a high-light LED, a servo, a turntable, and pictures on transparent paper or paper-cut silhouette. Projection shows as the light goes through the pictures, and changes as the turntable is spun by the servo.
The blimp is the carrier of the whole system. We use two balloons filled with helium to provide lift force, namely, the latex balloon above and the aluminium foil balloon at the bottom. The propulsion system consists of two coreless motor propellers and a servo. The servo is used to rotate the motors in the vertical plane so that the blimp can go up and down. In the horizontal plane, we use the difference speed between the two motors to allow the blimp turn left or right.
The controlling system works as the brain of the blimp. Under auto control, it reacts according to data from a distant sensor and a sound sensor. For manual mode, users can use the Android app to control the blimp directly.
Note that we also insert three LED tube into the latex balloon. When the noise from surrounding area is loud enough, the balloon can blink! This is just for fun anyway. However, we believe this makes advertising more effective.
Step 2: Prepare Materials and Tools
Compare carefully before you choose your materials. Well-chosen materials reduce much trouble later in constructing the product. To be more specific, for a blimp, you need to make sure that materials used are extremely light.
Here is a list of what we used for the blimp for your reference. Most of the materials are bought through Taobao.com (a platform of Chinese online shops).
Quantity/ Item/ Price (each)
1 Latex Balloon ¥ 2.90
1 Aluminium Foil Balloon ¥ 68.00
1 Jar of Helium (20kPa 22.4L) ¥ 155.00
1 Sound Sensor ¥ 5.00
1 Acrylic Board (3*400*600mm) ¥ 28.80
3 LED tube ¥ 0.10
2 9g Plastic Servo ¥ 8.80
8 SR Wires ¥ 0.54
2 Coreless Motor and Propeller ¥ 13.50
1 Plastic Foamboard (1.8*300*400mm) ¥ 2.80
1 High Bright LED Light ¥ 1.60
1 Aluminum Heatsink ¥ 3.00
1 Voltage Regulator ¥ 8.00
2 Motor Driver TB6612FNG ¥ 22.00
1 Bluetooth Module ¥ 35.00
1 Wood Batten (1*1*10cm) ¥ 1.50
1 Arduino Nano Board ¥ 40.00
1 Lithium Battery (7.4V 850mA) ¥ 30.00
2 Dupont Line ¥ 4.00
Total ¥ 482.82
Step 3: Build the Projection System
Projection system is the most important part of the blimp. As is introduced in the introduction, the projection system consists of an high-light LED, a servo, a turntable, and pictures on transparent paper or paper-cut silhouette. Projection shows as the light goes through the pictures, and changes as the turntable is spun by the servo.
First, make sure you choose a concentrated light because you want to have a clear projection. Also, the light need to fairly strong if you want to have projection in light environment.
The turntable and the servo serve to change the projection by spinning the paper-cut silhouette or transparent paper. You can also use a stepper motor to spin the turntable. However, stepper is much heavy than a servo. Remember every components should be as light as possible due to the limitation of lifting force provided by the helium.
Step 4: Build the Blimp
First, calculate the lift force (in kilogram) you need to decide the volume of the blimp accordingly using the formula below.
Volume = Lift Force/(density of air - density of helium)
Choose a blimp with your desired volume. You have two choices of balloons if you would like to buy online. One is made of latex, and the other Aluminum foil. The former one is lighter but the helium escapes much faster. You can also combine two of them just as we did.
Next, fix a board to the blimp where you will place the projection system, the propulsion system, the controlling system and the sensors. Fix carefully because you want to make sure your projection is stable.
Step 5: Build the Propulsion System
The propulsion system consists of two coreless motors and a servo. We use differential speed steering in horizontal direction – that is, to make the motors rotate at different rate when you want the blimp to turn right or turn left. We use servo to change the direction of motors to change the vertical direction.
Step 6: Program the Controlling System
The whole blimp is controlled by the controlling system, including an Arduino board, an Android app, a distance sensor and a sound sensor.
First place the Arduino board, the distance sensor and the sound sensor on the board connected to the blimp. Make sure that mass is evenly distributed on the board, otherwise the blimp will lose balance in its flight.
Then program the controlling system. We designed the blimp to have to mode: manual mode and auto mode. Under both mode, the projection is controlled by the Android app. Under manual mode, the Android app controls the blimp's direction and speed, while-as under auto control, the blimp is controlled by the Arduino board according to the data from sensors. The blimp keeps at least two meters from the ground to avoid being torn out by children (distance sensor) and flies automatically to the crowd (sound sensor).
Step 7: Done! Let's Advertise :)
Make a paper-cut silhouette or draw pictures on transparent paper for projection! Though it would be more convenient to use transparent paper, but we recommend paper-cut silhouette because that makes a clearer projection.
This blimp would catch people'e eye easily. Try using it in local cafe or department stores.
Have fun! Cheers.