Week 12 - Project Costing

 Table below shows the total cost that we have used to build a prototype of electronic wheelchair Using PIC microcontroller. Wheelchair body manufacturing process takes a total of RM 150.00 because we have a special book just for our project. The reason why we had to book it is because we do not have the equipment to build.

  This is only a rough estimate and does not include other costs with such vehicles, delivery services etc.

MATERIAL	PRICE PER UNIT (RM)	UNITS
Body casing	150.00	1
Motor DC	40.00	2
Front wheel	5.00	2
Back wheel	20.00	2
PIC 16F877A	18.00	1
RF Module	45.00	1
LCD	20.00	1
Drycell (1.5 volt)	15.00	1( pack )
Drycell ( 9 volt )	8.00	2
Component ( all )	40.00	Pack
Remote Casing	10.00	1
	Total	444.00

My partner and I have shared the money to complete this project and I would like to thank our families who gave us the funds to complete this project.

Week 11 - Installation Process

This week we will install all the circuits we've made as PIC Microcontroller circuit, transmitter circuit, receiver circuit, motor driver circuit to the body of the wheelchair.

This is PIC Microcontroller circuit.As you know, we are using PIC 16F877A.For addition we put an LCD to display the direction , forward ,reverse ,left and right .For reverse we put a buzzer so that the user know they are on a reverse mode.

This is motor driver circuit.This circuit will move the wheel. If the user push forward button so both wheel will move forward,for reverse both wheel will move reverse but for left and right there is little difference.If the user push the left button, the left wheel will move reverse and right wheel move forward and vice versa.

For motor driver power supply, we are using  (4) AA battery

This is transmitter circuit, this circuit will send the signal to the emitter circuit

Last but least, the emitter circuit and this circuit will receive the signal from the transmitter circuit

Week 10 - Wheelchair body manufacturing process

PROCESS BUILDING BODY WHEELCHAIR

Last week we completed the construction of circuit boards.So in week 10, we have started the process of making body wheelchair. In wheelchair body building process, we have had difficulty making because we do not have the equipment and we had to book it from the cutting steel shop. We have sent the diagrams and measurements for body wheelchair. We have chose to use aluminum metal because it is cheap, easy to cut, and lighter than other metals.

This diagram is a measurement of our electronic wheelchair.Since it is only a protoype we used a small scale to save time and reduce costs.The height is 15cm , the width is 15cm , and the length is 18cm

Picture above is an example of aluminum.Why we use aluminum because :

It’s lightweight—Aluminum weighs less by volume than most other metals. In fact, it is about one-third the weight of iron, steel, copper, or brass. This makes it easier to handle and less expensive to ship.

It’s strong—Aluminum profiles can be made as strong as needed for most applications. Cold-weather applications are particularly well-served by aluminum because, as temperatures fall, aluminum actually becomes stronger.

It’s non-combustible—Aluminum does not burn and, even at extremely high temperatures, it does not produce toxic fumes.

It’s seamless—With aluminum, complex shapes can be realized in one-piece extruded sections without having to use mechanical joining methods. This makes the parts stronger and less likely to leak or loosen over time.

Below are some pictures of the wheelchair body making .

The Result

Week 9 - Build a circuit board

BUILD A CIRCUIT USING PCB BOARD

Upon completion of purchase of goods needed in Jalan Pasar, I have started working to make circuit boards (PCBs). There are 13 steps to do it.

1.I had design my circuit board using PCB computer-aided design (CAD) software to draw my circuit board. 
2.Buy a plain board that is coated with a fine layer of copper on one side from a retailer.
3.Scrub the board with a scouring pad and water to make sure the copper is clean. (Let the board dry)
4.Print my circuit board's design onto the dull side of a sheet of blue transfer paper. (Make sure the design is oriented correctly for transfer.)
5.Place the blue transfer paper on the board with the circuit board's printed design against the copper.
6.Lay a sheet of ordinary white paper over the blue paper. Following the transfer paper's instructions, iron over the white and blue paper to transfer the design onto the copper board. Iron every design detail that appears near an edge or corner of the board with the tip of the iron.
7.Let the board and blue paper cool. Peel the blue paper slowly away from the board to see the transferred design.
8.Examine the transfer paper to check for any black toner from the printed design that failed to transfer to the copper board. Make sure the board's design is oriented correctly.
9.Replace any missing toner on the board with ink from a black permanent marker. Allow the ink to dry for a few hours.
10.Remove exposed parts of the copper from the board using ferric chloride in a process called etching.

• Put on old clothes, gloves and safety goggles.
• Warm the ferric chloride, stored in a non-corrosive jar and sealed with a non-corrosive lid, in a bucket of warm water. Do not heat it above 115 F (46 C) to prevent toxic fumes from being released.
• Pour only enough ferric chloride to fill a plastic tray that has plastic risers in it to rest the circuit board on. Be sure to do this in a well-ventilated space.
• Use plastic tongs to lay the circuit board face down on the risers in the tray. Allow 5 to 20 minutes, depending on the size of your circuit board, for the exposed copper to drop off the board as it etches away. Use the plastic tongs to agitate the board and tray to allow for faster etching if necessary.

11.Wash all the etching equipment and the circuit board thoroughly with plenty of running water.

12.Drill 0.03 inch (0.8 mm) lead component holes into your circuit board with high-speed steel or carbide drill bits. Wear safety goggles and a protective mask to protect your eyes and lungs while you drill.

13.Scrub the board clean with a scouring pad and running water. Add your board's electrical components and solder them into place.

Week 8 - Analysis about RF module

RADIO FREQUENCY 

To control the wheelchair, we have decided to use the remote control. We have used the RF Module because it's easy on the adoption and the price is cheap. We've bought in Jalan Pasar. For those who dont know what is RF Module, i will explain it in below 

An RF Module is a small electronic circuit which is used to receive, transmit or transceive radio waves on one of a number of carrier frequencies. RF Modules are often used in consumer applications including wireless alarm systems, garage door openers, industrial remote controls, wireless home automation systems and smart sensor applications. Due to RF modules not requiring line-of-sight operation, they are often used instead of infrared remote controls. A module is a self-contained component of a system, which has a well defined interface to the other components. An RF module is a functional integration of semiconductor devices.

The RF module, as the name suggests, operates at Radio Frequency. The corresponding frequency range varies between 30 kHz & 300 GHz. In this RF system, the digital data is represented as variations in the amplitude of carrier wave. This kind of modulation is known as Amplitude Shift Keying (ASK).

Transmission through RF is better than IR (infrared) because of many reasons. Firstly, signals through RF can travel through larger distances making it suitable for long range applications. Also, while IR mostly operates in line-of-sight mode, RF signals can travel even when there is an obstruction between transmitter & receiver. Next, RF transmission is more strong and reliable than IR transmission. RF communication uses a specific frequency unlike IR signals which are affected by other IR emitting sources.

This RF module comprises of an RF Transmitter and an RF Receiver. The transmitter/receiver (Tx/Rx) pair operates at a frequency of 434 MHz. An RF transmitter receives serial data and transmits it wirelessly through RF through its antenna connected at pin4. The transmission occurs at the rate of 1Kbps - 10Kbps.The transmitted data is received by an RF receiver operating at the same frequency as that of the transmitter.

The RF module is often used alongwith a pair of encoder/decoder. The encoder is used for encoding parallel data for transmission feed while reception is decoded by a decoder. HT12E-HT12D, HT640-HT648, etc. are some commonly used encoder/decoder pair ICs.

Pin Diagram;

Week 7 - Wheel for the prototype

The following tires we bought in Jalan Pasar :

REAR TIRES

1. Bolt hole rubber small caster 
2. Diameter: 40, 50, 65mm 
3. Wheel diameter: 40mm, 50mm and 65mm 
4. Loading capacity: From 20kg to 30kg 
5. Wheel material: Rubber wheel and bolt hole housing 
6. Plastic, cast iron, hard rubber, PP wheels are available 
7. Suitable for small trolley, small rack, furniture, etc. 
8. Quantity: 2pcs
9. Weight: 201g

FRONT WHEEL

1. Inner Wheel (Drive Side) Diameter : 45mm.
2. Outer Wheel (Nut Side) Diameter : 52mm.
3. Tyre Profile (Top Of Rim To Tyre Surface) : 7mm
4. Overall Height Of Wheel+Tyre : 66mm
5. Width Of Tyre : 26mm

Week 6 - Survey Motor

RF-020 4.5V Micro DC Motor Rc Toy

Last week we went to Jalan Pasar to buy things we need, right there, we have experienced difficulty in finding the motor because the motor that we find not a lot of stock and not all the stores that sell them. Finally, after discussion with my partner, we had purchased online. But online purchase price is slightly higher than the normal price

Specification

1.Size 17.1 diameter,18mm length

2.Power ; 0.1W-8W

3.Voltage ;1.5V-6V

4.Quite,Good price

5.Specification are customized

Micro Dc motor,Micro motor,Small electric motor

Typical Application ; Toys and Models,Radio Control Model

Note; Its just the typical technical data,The specification such  as voltage,speed,torque,shaft can customized

Dimension

Week 5 - Search component and equipment in Jalan Pasar

Here,my job is become easier as I know where to buy the component.If i had a problem in this project i will prefer the technician.Product is worth the price and the most important is the quality.I think Jalan Pasar is a good place for student to make the project because every component is there and facilitate student. 

FIGURE 1

FIGURE 2

FIGURE 3

FIGURE 4

FIGURE 4