Wireless Controlled Hovercraft (Wonder4)

The hovercraft is the device that can travel over land without wheels. Because of the enthusiasm for engineering and the requirement of the course Vg100, we, four students from UM-SJTU Joint Institute, formed the team Wonder4 and made our own hovercraft. Our hovercraft weighs 694g. Its size is 30cm×30cm×25cm.The light weight and small size makes it travel fast. It can go forward and turn under wireless control. To make this hovercraft, you should have fundamental knowledge of propellers and Arduino. You may spend 5-8 hours to finish this hovercraft.

For more information about our institute, please see http://umji.sjtu.edu.cn

Team Wonder4 Creation. Team members: Guo Ziqi, Hou Yijun, Chen Jin, Dong Zheng.

*The figure for each material is listed below in order.

(1) Electronics:

Three 64mm (4500V) brushless ducted propeller and three corresponding 40A brushless electronic speed controls (ESCs) (Figure 1.1)

PS2 wireless controller and receiver (Figure 1.2)

11.1V 2200mAh battery (with the matching charger) (Figure 1.3)

Arduino Uno board (with corresponding data line) (Figure 1.4)

20 cm male-female DuPont cables×15 (Figure 1.5)

One T-plug and one T-plug wire (Figure 1.6)

9 pairs of 3.5mm banana connectors (Figure 1.7)

(2) Materials:

Artificial silk cloth (>40cm×40cm) (Figure 1.8)

5 cm-thick EPE(Expand Aple Poly Ephylene) (>30cm×30cm) (Figure 1.9)

2.5 cm-thick EPE (Expand Aple Poly Ephylene) (>30cm×30cm)

(3) Tools:

Fiber reinforced tape (or electrical insulation tape or equivalent)

Ruler

Pencil/pen

Scissors/knife

502 glue (cyanoacrylate adhesive, i.e., “superglue”)

Hot-melt glue (HMA) and hot-melt glue gun

Soldering gun and electric soldering iron

(1) Solder each wire of a brushless ducted propeller to a male banana connector for later connection to the ESC. (Figure 2.1)

(2) Repeat step (1) for all three propellers.

(3) Solder each wire of an ESC on the side to be connected to the propeller (Figure 2.2) to a female banana connector. (Figure 2.3)

(4) Repeat step (3) for all three ESCs.

Connect all the paired banana connectors in the way shown in the figure to transfer power from the ESCs to the propellers. If the propeller does not generate thrust in the desired direction later, you might have connected wires in the wrong way. (Figure 3.1)

(1) Cut the 2.5cm-thick EPE to get a 25cm×25cm square base. (Figure 4.1)

(2) Cut a circular hole at the center of the base to accommodate the propeller. The diameter of the hole should be a bit smaller (approximately 3mm) than that of the propeller to prevent the propeller from dislodging. (Figure 4.1)

(3) Cut three rectangular grooves on the EPE base, whose depth is approximately 1.3cm. These grooves are enclosure to place the battery (location 1, Figure 4.2), the Arduino board (location 2), and the empennage (location 3). The approximate size and location of these grooves is shown in the figure below. Details on the construction of the empennage are given in step 5.

(4) Fix the propeller in the circular hole using the 502 glue. Make sure the propeller generate thrust in the desired direction. (Figure 4.3)

(1) Cut the 5cm-thick EPE for the empennage. The shape of the empennage is a rectangle, whose length and width are approximately 21cm and 12cm respectively. (Figure 5.1)

(2) Make two symmetric circular holes as shown in the image below to install two propellers. The diameter of the holes should be a bit smaller (approximately 3mm) than that of the propeller to prevent the propeller from dislodging. The approximate positions of the holes are shown in Figure 5.1.

(3) Fix two propellers in the holes with the 502 glue. (Figure 5.2)

(1) Cut the 2.5cm-thick EPE for a 25cm×25cm square frame, whose width is approximately 1cm. The purpose of the frame is to increase the friction when the hovercraft brakes. (Figure 6.1)

(2) Cut the silk cloth into a 40cm×40cm square. Cut a circular hole at the center to release air during operation. The diameter of the hole is approximately 1cm. (Figure 6.2)

(3) Fix the skirt to four sides of the frame with the hot-melt glue. (Figure 6.3 & Figure 6.4)

(4) Clip the redundant silk cloth at the four corners of the frame. Glue the silk cloth at the four corners again to prevent the air leak. Make sure the hole on the silk cloth is at the center of the frame. (Figure 6.5 & Figure 6.6)

(1) Fix the empennage in the appointed groove (location3, Figure 4.2, step 4) of the base with the hot-melt glue. (Figure 7.1) Make sure the empennage is perpendicular to the base so that the two propellers on the empennage blow backward.

Caution: The temperature of the hot-melt glue should not be too high, otherwise it may damage the plastic foam board.

(2) Solder six wires (3 ground wires and 3 power wires) of three ESCs to one end of the T-plug. (Figure 7.2)

Caution: Make sure the ground wires and the power wires do NOT touch! (Figure 7.3)

(3) Seal the T-plug with the hot-melt glue to prevent shortening during use. (Figure 7.4)

Caution: Recheck the connections before connecting it to your battery!

(4) Use the DuPont cables to extend the three wires to be connected to the Arduino Uno board (see Figure 2.2, step 2, to distinguish the wires) for each ESC. Seal the junctions with the fiber reinforced tape (or equivalent).

Caution: Remember the corresponding color of the extended cable for later connection!

In our case, we used the yellow wire for the ground wire (the black wire of the ESC), the blue wire for the power wire (the red wire of the ESC), and the green wire for the data wire (the white wire of the ESC). (Figure 7.5 & Figure 7.6)

(5) Use the fiber reinforced tape (or equivalent) to fix the wires and the ESCs on the back of the base. (Figure 7.7)

(6) Cut a hole (diameter approximately 1cm) in the base to pass the power line through. (Figure 7.8 & Figure 7.9)

(7) Use the hot-melt glue to fix the frame (and the skirt) on the base. (Figure 7.10)

Caution: The temperature of the hot-melt glue should not be too high, otherwise it may damage the plastic foam board.

(1) Connect the PS2 receiver and the three ESCs to the Arduino as shown in the schematic drawing below. (Figure 8.1)

(2) Connect the battery to the T-plug to test the connections. At this point you will hear a ring tone as the brushless propellers should initialize. If you do not hear a ring tone, recheck the connections.

(3) Disconnect the battery. Fix the battery and the Arduino board at the appointed positions (location 2, Figure 4.2, step 4) using the fiber reinforced tape (or equivalent). (Figure 8.2)

Code with Arduino programming software. The following code is for reference. Figure 9.1 shows the command of each button on the PS2 controller pad.

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#include

//for v1.6, you may download this library from http://pcsx2.net/download/releases.html

#include

PS2X ps2x; // create PS2 Controller Class

int error = 0; byte type = 0; byte vibrate = 0; Servo s1, s2, s3; int p=20;

void setup(){

Serial.begin(57600);

s1.attach(6); s2.attach(5); s3.attach(3);

error = ps2x.config_gamepad(13,11,10,12, true, true);

if(error == 0){

Serial.println("Found Controller, configured successful");

} else{

Serial.println("Error!");

}

}

void loop(){

if(error == 1) return;

ps2x.read_gamepad(false, vibrate);

if(ps2x.Button(PSB_PAD_UP)) {

s2.write(45); s3.write(45); delay(500);

s2.write(20); s3.write(20); Serial.println("Run!");

}

if(ps2x.Button(PSB_PAD_RIGHT)){

s1.write(36); s2.write(39); s3.write(33); delay(500);

s1.write(20); s2.write(20); s3.write(20); Serial.print("Turn Right!");

}

if(ps2x.Button(PSB_PAD_LEFT)){

s1.write(36); s2.write(32); s3.write(39); delay(500);

s1.write(20); s2.write(20); s3.write(20); Serial.print("Turn Left!");

}

if (ps2x.NewButtonState()){

if(ps2x.Button(PSB_L2))

{ s1.write(20); s2.write(20); s3.write(20); Serial.println("All Stopped!"); }

if(ps2x.Button(PSB_GREEN))

{ s1.write(32); Serial.println("Floating!"); }

}

delay(50);

}

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When the hovercraft is powered, you may find it to run unbalanced because of the uneven distribution of the mass. Depending on the actual conditions, adjust the position of the battery to optimize the weight distribution.

Congratulations! Now you can play with your hovercraft.

Caution: The ducted propellers can run very fast. Do NOT put your fingers in the fan! Do NOT let young kids touch the hovercraft when it is on!

For more information about our institute, please see http://umji.sjtu.edu.cn

Team Wonder4 Creation. Team members: Guo Ziqi, Hou Yijun, Chen Jin, Dong Zheng.