## Resistor Color Codes

Electrical & electronics engineering students and professionals often need to calculate resistor values from it’s color bands or colors from resistor value. This smart tool in your pocket can help you in finding resistor value from colors or colors from value. Wherever you are, in class room, LAB, field or in the market for purchasing different resistors with different color bands, this handy tool will help you. So, there is no need to remember codes. It supports 4, 5 and 6 bands resistors. It requires no special permissions.

This smart and free app will do this work for you.

### How It Works?

#### Colors To Value Calculation

Tap a color band to change it’s color. In the following figure current value of resistor is 47K Ohm.

Suppose we want to change this value by changing it’s colors as

1. 1st most significant color to brown.
2. 2nd most significant color to green.
3. 3rd most significant color to black.
4. 4th most significant color to orange.
5. 5th most significant color to brown.
6. 6th most significant color to blue.

Now we tap 1st most significant color and following color selection list will appear.

We select our 1st color brown from list. Now, color list will disappear and main screen will reflect this change and will show 1st color changed to brown as shown in the following figure.

Now, tap 2nd most significant color to change it’s color to green. Again color list will appear for 2nd band as shown below

We select green color from list and main screen will reflect the change as shown bellow

Here, we want 3rd color as black that is already black. So, we just leave it and move to next band that is 4th most significant band.

Tap 4th color and select orange color from color list that is shown below

Similarly, change next two colors 5th and 6th and finally we will find these results. Results show that this resistor is of 150K Ohm with 1% tolerance and 10ppm/C temperature coefficient.

#### Value To Colors Finding

Now, there is second case where we want to find out colors against a resistor value. Suppose, we want to find out colors against 10000 Ohm or 10K Ohm resistor. Enter value 10000 in the resistor input box as shown below

Note: Entered value will be considered in Ohm not K Ohm or M Ohm.

Now, tap/press “Done” button and app will show colors against 10000 Ohm/ 10K Ohm resistor as shown below.

### Disclaimer

We have designed this app at our best. We have tested it so many times but use it at your own risk. We will not responsible for any kind of loss in any form due to this app. If you find any bug or defect then please inform us at udigital.solutions@gmail.com. If you have any suggestions please, email us. We will be happy to hear from you.

## Wire Gauge Calculator

During transformer/ciol design we have to decide how much thick wire will be able to carry required amount of charge through it. Wires are divided according to their thickness/area of cross section. Each wire is assigned a number according to Standard Wire Gauge (SWG). This number is called SWG number of that wire. We know, a thick wire will be able to carry more charge than a thin wire. Here, I have considered circular mils (cmils) as unit of cross sectional area measurement.

Now, there is no need to look up a table/chart against your required value of current for wire selection. This smart and free app will do this work for you.

### How It Works?

It takes two values as input. First is Current that has to be passed through wire, so wire should be able to carry this value of current. Second value is Rate circular mils per ampere.
It generates two output values as well. First is SWG number of a wire that is safe for given value of current and it’s actual rate. Second value is the SWG number of next wire that may be or may be not near the required wire with it’s actual rate. You can decide yourself which SWG wire will be better for your current requirement.

First enter value of Current.

Now, enter value of Rate. In open air wires remain cool and can pass charge at more rate means with less cross sectional area a wire can pass more charge and so more current. But, when we use same wire in transformer/coil winding where wires are wound in layers, one layer over other and there is no air present between these layers but there is paper between them, so wires fail to get cool due to air, their charge passing capability is reduced and so, can pass charge at lower rates. Usually, we double rate (area) in transformers than in open air. We use 500 cmils/Amp value or more for transformers. There are so many other factors that affect this value, some of which are temperature, peak load time, working duration of machine per day etc. So, you have to choose better value of Rate considering all these factors.

Now, you press “CALCULATE” button and results will be shown to you as in the following figure.

### Disclaimer

We have designed this app at our best. We have tested it so many times but use it at your own risk. We will not responsible for any kind of loss in any form due to this app. If you find any bug or defect then please inform us at udigital.solutions@gmail.com. If you have a mind blowing idea of an app you can also share with us at this email.

## How To Develop LED Signage

What is visible, sells. Yes, if you want to sell your product it should be visible to others. Otherwise it will be like a waste put in your store or shop for years. If you’re looking for a reliable wholesale backdrops printing company, get in touch with the team at Craftsmen.

If you have a product/business, peoples should have awareness regarding this. LED sign boards are the one of the best ways to make your product/business visible to your customers. These have the following advantages

3. Helps a product/business inside of a building/plaza to get visible to outside people.
4. Visible during dark light times, in the evenings, nights and cloudy environment.
5. More visible than painted or printed sign boards due to light.
6. More noticeable to people due to blinking/flashing lights with attractive colors.
7. Lights of different colors make the environment more pleasant.
9. Better return on investment. Initially, it looks costly but it returns your money back usually within 1 to 3 months.

So, it is worthy to make LED sign boards for others to support their business and earn handsome amount of money for you as well. I have written a book How To Develop LED Signage. In this book I have tried to teach you, how we can develop these LED sign boards. You can purchase this book from here. If you find any errors/mistakes or want to give suggestion please inform me at this email id developledsignage@gmail.com. I will be happy to hear from you for the improvement of this book. Thanks…

## Introduction

In 1980 Intel introduced a microcontroller standard MCS-51 also known as 8051. This standard provided a base for microcontrollers and ease of development for microcontroller based applications. This is simplest microcontroller with less but most widely used peripherals that are enough for majority of applications. Less peripherals in a microcontroller make it simple to learn and reduce learning time and efforts while more peripherals and features in a microcontroller make it complex to learn and increase learning time and efforts. Standard 8051 microcontroller has less peripherals and so best suits for newbies and students as compared to other microcontrollers like PIC, AVR or ARM that are complex to understand (due to more features and peripherals). Most of the developers easily learn and develop 8051 based applications. So, it’s simplicity attracts developers. It has not just a microprocessor but has important resources and peripherals on a single chip that makes design simple, low cost in terms of money, time and efforts as compared to microprocessor design that becomes complex and costly. Although external resources and peripheral can also be attached like in microprocessor based design. All peripherals can be mapped in memory address space of 8051 and this feature is also not available in most or all of other microcontrollers like PIC and AVR (however some of them may have this feature but not all). Because of this feature we can design Single Board Computer (SBC) system on 8051 microcontroller. Tools and IDEs are easily available for the development of 8051 microcontroller. Ability to develop 8051 based application is necessary to acquire degrees of various disciplines of engineering. Due to these characteristics 8051 microcontroller is one of the most widely used microncontroller today. After Intel different companies are now producing variants of 8051 standard microcontroller. All of these are based on 8051. Some of these companies are Atmel, Philips, Dallas, Infineon.
8051 based micontroller have the following major parts in it

1. Memory
• Program Memory
• Data Memory
• Special Function Registers (SFRs)
2. IO Ports
3. Interrupts
4. Timers
5. Serial Port

### Memory

There are 4 types of memory in standard 8051 microcontroller.

#### Program Memory

In standard 8051 microcontroller there is 4KB of on-chip or internal memory where program to be executed resides. This program is executed when microcontroller power is applied in the target circuit. This program is transferred using a programmer/burner device from PC to 8051 microcontroller.

#### Data Memory

In standard 8051 based microcontroller there is 128 bytes of data memory. Data memory is the place where our program data or variables reside. Stack also occupies space in this area of memory. This area belongs to address space from 0x00 (0 decimal) to 0x7f (127 decimal).

#### Special Function Registers

These are the registers that control or store status of specific behavior or data related to a function of 8051 microcontroller. SFRs belong to address space from 0x80 (128 decimal) to 0xff (255 decimal). But there are only 21 SFRs in standard 8051 microcontroller. Remaining 107 locations may be used by other derivatives of 8051 but not in standard 8051 microcontroller.

As it’s name shows this is a memory area in which single bit can be addressed or accessed. There is no need of reading or writing whole byte to access a single bit. However we can also access whole byte as well. There are 16 bytes memory for this purpose and belongs to address space from 0x20 (32 decimal) to 0x2f (47 decimal).

### IO Ports

Standard 8051 has 4 IO ports of 8 pins each. These ports are Port 0, Port 1, Port 2 and Port 3. These ports are used to communicate with external world. Some pins of ports have more than one function.

### Interrupts

Interrupt is the signal to CPU for an event that requires immediate attention of CPU. An interrupt may be a hardware or software generated. Standard 8051 microcontroller has 5 Interrupts sources. These sources are

1. External Interrupt 0 (INT0)
2. Timer 0 Overflow Interrupt (TF0)
3. External Interrupt 1 (INT1)
4. Timer 1 Overflow Interrupt (TF1)
5. Serial Port Interrupt
Serial port interrupt is further divided into

2. Transmit Interrupt (TI)

### Timers

Timer is resource that is used to count events or to calculate time duration of an event or to simply calculate delay. In standard 8051 microcontroller there are 2 timers called Timer 0 and Timer 1. Both of these timer can be configured and run independently. Timers also generate overflow interrupt during counting.

### Serial Port

Serial port is a hardware resource in 8051 microcontroller that convert serial stream of bits on receive pin “RxD” and convert it into parallel data and convert parallel data into serial stream of bits that is transmitted through transmit pin “TxD” (each bit one by one). Serial port is also called UART (Universal Asynchronous Receiver Transmitter). Serial port also uses a timer for calculation of baud rate or duration of a single bit. Serial port has receive and transmit interrupts associated with it. Using this serial port we can connect our 8051 microcontroller with PC, some other microcontroller, mobile or modem.

## Resistor Color Code Calculator

Resistor is a basic building block in electronics circuitry. Resistor is used to limit current in a circuit because it presents opposition to charges. Resistors that are reasonably small, their values are shown as color bands on them. These color bands represent the value of that specific resistor.

Here is a simple free software tool “Resistor Color Code Calculator” by Micro Digital to easily calculate a 4 band (some times called 3 band) resistor value without knowing color codes. This is best for hobbies and new student of engineering.

You can select/change color for each of the four bands using combo boxes.

In the following example the resistor value is 4.7 K Ohm. Some times it is also written as 4K7 Ohm.

Resistance-Color-Code-Calculator.exe

Visit Projects Page

## How To Convert C Code Into Assembly in Keil 8051 Compiler

You can convert C code into assembly by following these steps.

1 – Right Click on Target & select “Options for Target” like in the following diagram

Now the following dialog will appear.

2 – Now select “Listing” Tab and new page will appear like in the following figure

3 – Now tick “Assembly Code” check box and press OK button.

5 – Check newly generated “lst” extension file like main.LST in this example.

This file will have actual C code and Assembly code generated corresponding to this C code. In this way problem is that compiler generates routines with labels that are not self exploratory. This compiler generated assembly code is no more optimized. But it may help us in so many ways. Some times it may be useful for converting our previously written C code into assembly and save our time to code it again from beginning.

Go to Main Projects Page

## 8051 4 Digit Electronic Code Lock with LCD and Keypad

### Description

It’s an example of 8051 4 Digit Electronic Code Lock with LCD and Keypad.

### Detail

For detail of LCD interfacing please see 8051 To 16×2 LCD Interfaing.

For basic operation & components used in an 8051 based microcontroller based systems see
8051 Basic LED Flasher.

### Related Projects

8051 Basic LED Flasher

8051 To 16×2 LCD Interfaing

8051 Timer0 As Second Counter On 7 Segment

8051 Digital Clock On 7 Segment (Non Multiplexed)

PC Serial RS232 Port Interface To 16×2 LCD

8051 Calculator with 16×2 LCD and Telephone Keypad

## 8051 Calculator with 16×2 LCD and Telephone Keypad

### Description

It’s an example of 8051 Calculator with 16×2 LCD and Telephone Keypad.

### Detail

This example project describes how can we interface 16×2 LCD and keypad. Simple Telephone keypad is used for this project. Initially when system is started 0 is displayed on 2nd row and right most column. First user enters first operand then select an operation by pressing ‘*’ key once or again and again. When user presses ‘*’ key first multiply operation is displayed on left most upper corner. By pressing ‘*’ key again and again changes operation to be performed and this operation is displayed on upper left corner of the 16×2 LCD. Operation in this version are simply 4 arithmetic operations *,+,- and /. Maximum of 4 digit operand can be entered in this version. After selecting operation user will enter 2nd operand then press ‘#’ key that will perform selected operation and will show result on lower right corner of 16×2 LCD.

For detail of LCD interfacing please see 8051 To 16×2 LCD Interfaing.

For basic operation & components used in an 8051 based microcontroller based systems see
8051 Basic LED Flasher.

### Related Projects

8051 Basic LED Flasher

8051 To 16×2 LCD Interfaing

8051 Timer0 As Second Counter On 7 Segment

8051 Digital Clock On 7 Segment (Non Multiplexed)

PC Serial RS232 Port Interface To 16×2 LCD

8051 4 Digit Electronic Code Lock with LCD and Keypad

## Cricket Score Board using 8051 and 7 Segment

### Description

It’s an example of Cricket Score Board using 8051 and 7 Segment.

### Detail

In this example we have interfaced 7 segment and touch buttons. Initially score of 0 is displayed on seven segments. When user presses button B0 4 is added in the score. When B1 is pressed a score of 6 is added. On pressing B2 1 is decremented from score. And when B3 is pressed 1 is incremented in the score. This score is also updated on seven segment when it is changed. For detail of how can we interface 7 segment displays please see 8051 To 7 Segment Display Interfacing.

For basic operation & components used in an 8051 based microcontroller based systems see
8051 Basic LED Flasher.

Cricket-Score-Board-using-8051-and-7-Segment.zip

### Related Projects

8051 Basic LED Flasher

8051 To 7 Segment Display Interfacing

8051 Timer0 As Second Counter On 7 Segment

8051 Digital Clock On 7 Segment (Non Multiplexed)

8051 Digital Clock On 16×2 LCD

PC Serial RS232 Port Interface To 7 Segment

More Projects

## 8051 Timer0 as Second Counter on 7 Segment

### Description

It’s an example of 8051 Timer0 as Second Counter on 7 Segment.

### Detail

In this example we have configured 8051 timer0 for time calculation. There are 4 different modes for timer0 in 8051. We have selected 8 bit auto reload mode. In this mode timer0 hardware is automatically reset upon overflow to a predefined value and again starts counting up. Timer0 counts up 1 after 12 clocks of main system clock oscillator. So if we are using 12 MHz crystal then timer0 input frequency will be 1 MHz.
Here in this project system clock is of 24 MHz and timer0 input clock is 2 MHz. It is reset to value 6 after each overflow. Simply each timer interrupt is occurred after 125 micro seconds. And so in this way if 8 interrupts has occurred then 1 millisecond has passed and if 8000 interrupts has occurred then 1 second has passed and so on. In this way we can calculate hours and minutes also. This time in seconds is updated on 2 digit 7 segment displays regularly. For detail of 7 segment interfacing please see 8051 To 7 Segment Display Interfacing.

For basic operation & components used in an 8051 based microcontroller based systems see
8051 Basic LED Flasher.

8051-Timer0-as-Second-Counter-on-7-Segment.zip

### Related Projects

8051 Basic LED Flasher

8051 To 7 Segment Display Interfacing

Cricket Score Board using 8051 and 7 Segment Display

8051 Digital Clock On 7 Segment (Non Multiplexed)

8051 Digital Clock On 16×2 LCD

PC Serial RS232 Port Interface To 7 Segment

More Projects