A chair is such a basic piece of furniture that often times it is taken for granted. With its sturdy 4 leg design and it's soft seating area, so inviting for people to just, well, sit and enjoy its presence. It is a proven reliable technology built for our comfort, rest and enjoyment. There have been plenty of times that I have looked forward to encountering a chair throughout my life. Yet what if the chair had an emotional side? What if chairs had desires or opinions or changed their minds about you placing your butt on them. What if the chair refused to play the role it has been destined and created to play?

We thought about a chair and how perfectly reliable it is. Unlike my computer or software, a chair will work all of the time perfectly, just as it was intended.

The chairs that we created do not let you sit on. They will not just sit there and have you sit on them quietly. Below are two such chairs-

1- 'Angry" chair- It that will definitely let you know how it feels by screaming and shaking violently. (Thanks to a cement mixer motor attached to the seat.)

2- "Sad" chair- This one will cry because it can not or doesn't know how to remove you from it. This chair will cry and begin to wail loudly. If you still don't get off, its significant amount of tears will be felt by your butt, through whatever it is that you are wearing while sitting on it.

Step 1: Go Get Stuff

You will need:

- (x1) chairs (Amazon)

- (x1) chair with steel base (industrial chair) You can get any chair that is similar to this

- (x2) Arduino nano (V3.0 ATmega328P)

- (x2) Speaker (3 W, 8 Ohm)

- (x2) Mp3 module (DFPlayer Mini)

- (x2) SD card (Sandisk 4GB MicroSDHC)

- (x2) Pressure-sensitive conductive fabric (10.3 x 8.7 x 0.2 inches)

- (x2) 4 X 1.5V AA Battery Case Holder ( Ogrmar On/Off Switch)

- (x8) AA Battery ( Energizer AA size Alkaline battery)

- Vibration motor (Power 0.28kw Vibration 2.9kn Force (300kgf) Voltage 110V 50/60Hz)

- Router speed control (MLCS 9410 20-Amp)

- Peristaltic pump (Water Pump 63 GPH 4.2W)

- Peristaltic pump tube (10 feet 5/16 ID - 7/16 OD)

- Power Relays (Fujitsu Components FTR-F1CA005V)

- Copper Foil Tape (Conductive Adhesive 1inch)

- 5v Relay Module (relay)

- (x4) 1/4" by 2 1/2" bolts, (x4) nuts for these bolts, (x8) larger washers for the bolts

Step 2: Making Pressure Sensor

This pressure sensor will be located on the chair so that the sensor can notice when you sit on the chair. Decide a shape of the pressure sensor. You need to create two separate tabs for the two layers of conductive fabric and that these should not touch each other. Make five holes in the thick paper evenly (See picture). Cover the hole with a conductive fabric on top and bottom of the thick paper by using double-sided tape. Connect the five conductive fabric with the copper foil tape.

Step 3: Sad Chair: Making and Code

Mechanism (how it works):

1. You will sit on the chair and the switch, which I explained from the previous step, is pressed.

2. If the switch is on, it activates DFplayer and plays sobbing sounds (file named 0001, 0002, 0003).

3. While playing sound files, the motor(water pump) secretly propels to sneak water on the chair.

Tips:

1. For making people feel the chair like a normal chair they use, we attached every components under the seat and seal them with a box.

2. Sometimes a motor stops suddenly, which you can doubt the pipe inside the motor stuck, then, you can pull each side of pipe and make it stretched out.

Step 4: Angry Chair: Solder and Code

Mechanism (how it works):

1. Like the sad chair, when you sit on the chair, the switch is pressed (which means it's on).

2. Then, it plays audio files named 0002,0003.mp3 which warns you to get off.

3. After alerting you, it activates a strong vibration motor to make you feel disastrous.

Tips:

1. If you want to control the speed(give variations on speed) of the motor, you can use a fan controller, otherwise, you may use a power relays to manipulate on and off status.

2. When the fan controller is on, it creates a strong magnetic field which makes you shock if you touch it, thus I highly recommend to seal it with a box like the image above.

Step 5: Pressure Sensor Install in the Chair

This is an old steel chair where the seat base is a thin steel/metal plate. I was able to unscrew the leg base from the seat. Placing the motor in the middle of the seat plate I used a marker to mark the holes and then I used a 1/4" metal drill to slowly drill the holes for the motor to be attached. This motor was pretty heavy and it would be helpful if someone assists to hold it. With this particular steel chair, I did not need to take the entire cushion off. Luckily I was able to have enough space to slide the 1/4 7" x 7" piece of plywood under the cushion and align with the holes.

I used the 2 1/2" by 1/4" bolt with a nut and washers on both sides of the metal seat as can be seen (partially) from the images. After the motor was attached the pressure sensor was then slid right under the vinyl covering and over the cushion.