Final Project documentation and presentation

I planned to make the inflatable coin bank with the shape of Teddy bear. You can see in my idea sketch which I shown in week 1 page of my website. Later I changed to make the outer appearance of my prototype as a chicken with it’s belly getting inflates while putting the coin.

Big Belly: is an inflatable coin saving bank that grow in size when you insert coins. The project depends on IR sensor model to sense the inserted coin and control an air pump to inflate a balloon. The project is inserted inside stuffed toys made out of stretchable clothes with opening to insert coins. When the bank is opened to collect the money, the balloon will deflate, this will encourage kids to never open the bank until the balloon is fully inflated.

Part List/ Bill of materials:

1- Electronics: ATtiny44 , A4953 motor driver IC,2 X 2 header, 2X3 header,Capacitors(0.1,1 and 10mF),regulator IC (5V) and 10k ohm resistor

2- IR module

3- 5v micro air pump

4- stretchable for toy pattern

5- Flexible Hose

6- zip ties

Processes used:

1- 2D/3d design

2- 3d printing

3- Laser cutting

4- Vinyl cutting the logo

5- Electronics ( Inputs/outputs/Schematics/PCB)

6- Embedded Programming

2D /3D design and Parts created

Main mechanical structures included in my project are created using following methods.

I used sindoh 3D printer(My personal) to 3d print the designs. The printed out put quality of the printer is very good as compared to the one used earlier.

part	Did what	processes Tools and machine
T Shape connector	Designed + 3D printed	Fusion 360 + sindoh 3d printer
Balloon adapter	Designed + 3D printed	Fusion 360 + sindoh 3d printer
Top cover	Designed + 3D printed	Fusion 360 + sindoh 3d printer
Bottom Cover	Designed + 3D printed	Fusion 360 + sindoh 3d printer
4 sides walls	Designed + Laser cut	Fusion 360 + laser cutter
Coin extendable slot	Designed + 3D printed	Fusion 360 + sindoh 3d printer
logo	Designed + Vinyl cut	cameo silhouette
totoro toy pattern	Designed + Laser cut	Inkscape + laser cutter

1-2D/3D design(The Bank Design)

The Main Bank unit is designed to be small to fit inside a normal Stuffed toy 10x10x10 cm. This time I used vision 360 to 3D design. Earlier I was using Onshape for my designs. As I want to try new application, I tried with this and this is different from the web based cad application.I downloaded the free version of it and started my design.The speciality which I liked is I can directly 3D print my design and as well as designing is in offline.

My materials for the side walls and other mechanical structures are as shown in the above picture.

The design has 4 wood faces that will be cut using 3mm Mdf wood with the Laser Cutter, top cover and the base will be 3D printed.

The above shown are the rendered designs of my container box.Then I designed T shape connector for the air pump,bolts,air valve,Bottom cover,screw,Coin sliding slot,Top part etc .

T connector design

I 3D printed these parts using sindoh printer.I provided the screen shot of these parts slicing using 3D WOX application for sindoh 3D printer in below section.Coin slider is not printed. Because this is a structure for future development option. If the structure is large. I can fix this over the box.So that Coin can easily glides through this structure.

2-3D Printing the parts balloon adapter(Air valve) ,T connector, top part,Bottom part, screws and bolts bottom part etc are done successfully

Bottom part

Nut and screw

TOP part

Testing by assembling the parts

Connecting baloons with pump

I checked the assembly of my printed design,The air valve and other stuffs are tested and it was good enough to fit them well.

3-Laser Cutting the walls

The side walls of the container box is to be laser cut. I designed press fit type box with the required holes and slots and laser cut the design.

IMG_20170609_144439

IMG_20170609_144143

The laser power and speed are adjusted to proper value so that I could get the good ouput.Assembled the box as shown in the image shown earlier.

4-Vinyl Cutting the Logo:

I used Inkscape to design my logo which can be sticked on my box .I designed the sticker as shown below.

Inkscape designing

Final sticker design

I craeted the PNG file as shown above using the inkscape.. I loaded the PNG file in to Silhouette cameo Application used for vinyl cutter.

I got he sticker as per my design.I used yellow color vinyl for the sticker as material and using the transfer tape. I pasted the sticker at one side of the box.

IMG_20170612_170857

The problem faced here is that The writings or the Caption I made in the design was unable to get properly while transfering. You can see the caption in my picture above.

So I Now I decided to go with out the caption no

5-Electronics

First of all instead of going directly to board ,I choosed to test My Electronic part of my concept.For testing of the idea using the best available electronics prototyping system here, I used EBOT system (For testing ONLY)

https://en.wikipedia.org/wiki/Ebot_(microcontroller).

The IDE for this is simple. Blockly based drag and drop system which generate Arduino Code automatically corresponding to the blocks used.

The Board and the project looked like this.

IMG_20170608_230614_01

Electronics part testing using E Bot system

E BOT Application

Electronics design:

In the Electronics design process, I already created a board in the INPUT week. In that there is Power supply connection,5v IC(voltage regulator),IR sensor, H-Bridge motor driver,Button(Using as limit switch) and 2 x 2 headers for the DC motor connection.

Here iam again including the Schematic,Board screen shots of Eagle design.

Eagle schematic

Eagle Board design

Can read the detailed documentation of designing, milling and programming for the Input process in INPUT week

The main thing in the input week is the IR sensor. I already got the result of this board working for input section in this week.

Now the next is regarding the OUTPUT. I have attached the PUMP atachment header for the out put and motor cdriver IC in this.AS you can see, I have done the out put week assignment as a DC motor connected to A4953 motor driver. I got he output in that week with the proper working of the motor.i referred the board diagram given in fabacademy archive here .

I added this motor driver and the output pins (connection headers) and required components in the design of input board which I can use for the project.

So now I have to connect the Air pump which works on the same voltage as that of DC motor.

Please refer for further reading to week 10 -OUTPUT Devices: Week 10 OUTPUT

Please refer to further reading to week 13 -INPUT Devices: Week 13 INPUT

H-bridge Motor driver.

For controlling a DC motror with a Micro controller, A motor driver is required. Here I am using A 4953 motor driver IC.

A4953 Designed for pulse width modulated (PWM) control of DC motors, Allegro's A4954 is capable of peak output currents to ±2 A and operating voltages to 40 V. Input terminals are provided for use in controlling the speed and direction of a DC motor with externally applied PWM control signals. Internal synchronous rectification control circuitry is provided to lower power dissipation during PWM operation. Internal circuit protection includes overcurrent protection, motor lead short to ground or supply, thermal shutdown with hysteresis, undervoltage monitoring of V_BB, and crossovercurrent protection.circuitry is provided to lower power dissipation during PWM operation. Internal circuit protection includes overcurrent protection, motor lead short to ground or supply, thermal shutdown with hysteresis, undervoltage monitoring of V_BB, and crossovercurrent protection.

The A4953 is provided in a low-profile 8-pin.

Features
Low R_DS(on) outputs Overcurrent protection (OCP) Motor short protection Motor lead short to ground protection Motor lead short to battery protection		Low Power Standby mode Adjustable PWM current limit Synchronous rectification Internal undervoltage lockout (UVLO) Crossover-current protection

Datasheet for the A4953 is here

Reference: Digikey

Some important datas and ratings I referred from the datasheet:

To Control the airpump used for this, I used the following logic table.

For the supply voltage to the board, I used 9V battery.

IR sensor:

IR transmitter and reciever

IR transmitters and receivers are present in many different devices, though they are most commonly found in consumer electronics. The way this technology works is that one component flashes an infrared light in a particular pattern, which another component can pick up and translate into an instruction. These transmitters and receivers are found in remote controls and all different types of devices, such as televisions and dvd players. Peripheral devices that include this technology can also allow a computer to control various other consumer electronics. Since infrared remotes are limited to line of sight operation, some products can be used to extend the signals over a hardwired line transmissions.
Most common consumer electronic remote controls use infrared light. They typically generate infrared using light emitting diodes (LEDs), and the main component of a receiver unit is usually a photodiode. A remote control flashes a pattern of invisible light, which is picked up and then turned into an instruction by the receiver module. The parts necessary to construct transmitter and receivers are typically inexpensive, but these systems are limited to line of sight operation.The detailed

6-Embedded Programming

Using the A4953 logic tables and other conditions to work my pump, I Created a code in arduino IDE that look like this.

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