engaging Diy Microcontroller Projects! - Digital proclamation law

1.1) Objectives

In this project, we look at how we can implement a "Digital 2.4km Run proclamation System".

1.2) Design Methodology The whole design process can be partitioned into a pyramid as follows.

Specifications and Requirement Capture

Components comprises of Led display, a voice synthesizer, a keypad and an infrared Interceptor.

1) Button on keypad is depressed when the runners are flagged off.

2) The display will show continuously the time lapse at 0.1 second resolution.

3) When the infrared ray over the track of the runner is intercepted, the time at the point of interception will be announced.

4) The time will also be logged on the system.

System Concept

The system is capable of displaying the time on the Led display once the start button is pressed. At the same time, the infrared interceptor is started, and is continuously checking if its infrared ray is intercepted, and if so, trigger the system to announce the time of interception to the runners, and make a log of the time of interception to the system. The runner should also be able to see the time they took on the Led display. If the Stop button is pressed, the timer should stop timing, and log the time of disconnection on the system. When disconnected, the infrared interceptor and Led Display are also to be off.

Working Principles

In order to implement such a system, background knowledge about the workings of each component in the system is required. In this case, we need to know the controlling of the Led display, the voice synthesizer, the infrared interceptor, and the keypad, and finally we will show a flowchart on integrating these devices.

Led Display

As found, Leds run on about 2 volts, hence we need a simple resistor in series to Ant. Eject some of the voltage and limit the current the Led can draw. Assuming an input voltage of 5V and a current of 10 ma, and applying V=Ir, we can find the required resistance as R = V/I = (5 - 2)/.010 = 300 ohms.

To have a brighter Led, I can pick the resistor as 270 ohms allowing more current flow, making the Led brighter. With that, the new current drawn is I=V/R = 3 / 270 = 11ma.

Given a 7 segment Led, the basic configurations looks as follows:

The 7 segment Led tasteless Anode will be adopted because the microchip is now driving up to 8 Leds (segments) at a time off a singular port. Just as each I/O pin has a limit to the number of current it will source or sink, each port also has a limit. To do the least damage, we are sinking the current to ground rather than sourcing it to 5 volts.

To add more displays, the cathodes from a singular segment of each display are all connected together and then connected to a Pic I/O line straight through a series resistor. The tasteless anode is made controllable by a Pic I/O pin. In this way, the segment value for a given display can be configured and straight through turning on the anode for that display, we can see the message. The same policy can be applied to the other Led displays, and when a favorable timing is chosen, we should be able to see the full display of all Leds without flicker. The favorable timing is chosen by finding out the time constant of the Led using a datasheet, and from this value, we can pick the accepted refresh time such that it is less than the time constant, allowing the Led to appear spellbinding all the time.

Also a transistor is placed between the Pic and the tasteless anode to each display. Since the current for the whole display runs straight through this one pin, it could overload a singular I/O line. To overcome this issue, the transistor amplifies the current drive quality of the I/O. To operate, put ground on the I/O pin to turn on the transistor and enable a given display, or put 5 volts on the pin to turn off the transistor and the display.

The form below shows the case for 4 Led displays:

With this way of using Led displays, we can plump the numbers to display based on the configuration as follows:

Take segment 'dp' as the Msb, and segment 'a' as the least necessary bit, and to enable a singular segment to light up, we must apply a low to the corresponding segment, since it is an active low input. The table below shows the segments which we have to operate to display each digit from 0 to 9.

Voice Synthesizer

In order to announce the time of interception to the runners, there is a need to store each digit from 0 to 9 in human voice and depending on the situation, announce the strict time by finding the location of the voice segment corresponding to the strict digit.

As found, the average human voice frequency is estimated at 2 Khz to 4 Khz. Hence, we need to sample at a Nyquist sampling rate of f(sample)>2*f(voice)= 8 Khz. We pick the minimum sampling frequency as 8 Khz. Given this frequency, it implies that the voice should be sampled every 1 / 8 Khz = 125 us.

The voice corresponding to a singular digit can also be broken down into distinct syllabus, and each syllabus should take up equal frequency of sampling. For example, the rate of sampling a singular digit of 3 syllabuses will have each syllabus taking up 8000 / 3 = 2667 Hz To start, we can use the sound recorder in case,granted under Microsoft Windows to store the voice as a wave format. We have to set the settings as 8 kHz, 8 Bit, Mono. Next, we take off the header bytes by using a binary editor such as Hexplorer. After which the voice data corresponding to each digit can be stored in the Eprom, and being referred to as and when needed.

To recover an analogue signal from the digital signal stored in the Eprom, a Digital to Analogue converter is used. The digital signal has to be fed to the analogue converter at a rate of 8 kHz or every 125 us. The yield from the D/A is then fed into a Lpf of 4 kHz to take off any noise. The final yield is then fed straight through a power amplifier such as Lm386, and straight through current amplification, we can accumulate load matching with the 8 ohm speaker, and get max power output.

Infrared Interceptor

The infrared interceptor is made up of the infrared Led, the infrared detector Gp1U5. The infrared detector contains both the Ir detector and a small circuit that detects a 40kHz modulation. This detector is able to reject noisy light signals and hence has better performance. It works by detecting the modulated infrared light from the Ir Led, and straight through amplifier and band pass filter of 40 Khz, get a clean signal.

If there is any runner crossing, the detector will sense a dissimilarity and we can use the signal to feed into the interrupt pin of the microprocessor which will then announce the time and also make a log on the system.

Keypad

The form on the left shows the schematics of the 4*4 keypad. The needed outputs can be fed to the Programmable Peripheral Interface 82C55 of the microcontroller for reading the status, and straight through the 82C55, settle the type of interrupt invite to the microprocessor.

In our system, button 1 is designed to start the run, the Led display and the infrared interceptor. Button 2 is designed to stop the run, turn the Led display and infrared interceptor off. All other buttons should not interfere with the doing of the system.

Realization

We use a flowchart to show how these distinct devices can work together.

With this done, we have already gotten ourselves a very concrete design on paper, and it is now time to implement this into stock straight through the necessary hardware and software implementation.

Hope my little project has inspired you with lots of creativity for you to start your very own Diy projects as well.

engaging Diy Microcontroller Projects! - Digital proclamation law

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C Programming For the Pic Microcontroller

The C programming language surely reigns consummate in the embedded electronics community. Microprocessors can be found in 99% of all electronic appliances these days from car radios to cookers and it is the software that the microprocessors run that gives personality to the whole design.

Many hobby electronic enthusiasts cut their teeth on microprocessors by learning assembly language. Admittedly the Pic Microcontroller from Microchip is the processor of choice for many beginning on this path.

Assembly language presents a free of payment entry into this shop - ideal for the beginner on a little budget. Any way assembly language is somewhat laborious if a complicated task needs to be coded. Now free of payment C compilers are ready for download, so students can begin their programming sense in a high level universal language that can be used on many other high and low end microprocessors.

Assembly language is little to use with one single processor house and if the engineer migrates to someone else processor, he has to start again from scratch. C is a universal language and it is the headache of the compiler designer, not the engineer, to make sure the C code is compatible with the processor.

Most software written by non-hobbyists is written in C. Schedule snippets can be collected and used across many projects with separate processors until whole libraries of code are amassed. Code writing then becomes a simple task of choosing which code functions are needed and gluing them together - a task that the C programming language is particularly distinguished to.

Simple C for the Pic microcontroller gets anyone with little or no sense of C or Pic microcontrollers programming in as little as half a day.

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The invention of microprocessor was a milestone to the introduction of microcontroller. The first microprocessor was pioneer in 1971 by Intel. It was the 4 bit microprocessor with the clock speed of 740 Khz. It knows as Intel 4004 and the first commercial Cpu in singular chip.

Three years later Intel had manufactured 8 bit microprocessor of Intel 8080. It was determined by many to be the first true microprocessor general purposes used. It has used in variety applications such as traffic light and cash register. The Altair 8800 was one of the first computer as well used the microprocessor.

The complexities of microprocessor had driven to introduce of microcontroller. In order to be used microprocessor other component need to be adding externally such as memory, input port and yield port. Any way microcontroller had combining the Cpu, memory, peripheral, input-output function and analog to digital converter in singular chip.

The year of 1976 was a necessary in microcontroller history. Intel had invented the first world microcontroller. The microcontroller were Intel 8048 and Intel 8748. Since then the uses of microcontroller was growth every year with dozen of vendors. The tasteless vendors to the day were Intel, Freescale, Microchip, Arm and Atmel.

In 1993, the introduction of Eeprom had pump up Microchip sales with their famous chip of Pic16C84. It is allowed to be erase memory electronically and quickly. This electrically erasable memory made it cost less than Cpu that required quartz "erase window" for erasing Eprom.

Later on the Pic16F84 had introduced due to replacing Eeeprom with flash memory. As the affected the cost of singular chip plummeted over time. In 2009 the cheapest 8 bit microcontroller available with cost of .25 in quantity of thousands. Nowadays the microcontroller are low-cost and easily available for hobbyists, with large online communities nearby inescapable processors for hobbyists, with large online communities nearby inescapable processors.

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ideas manufacture ideas - All-In-One Versus Best-of-Breed

Complex systems are often designed by using easy rules and principles. One (of many) such an organizing principle is about selecting a All-in-One approach or the other - Best-of-Breed design.

The software of Microsoft (and many others) "hide" an All-in-One approach. This is not "bad", nor "good," but just a preference. We know this from the mix of the operating system with other functionality. And a recent incident in Internet Explorer reminded me of this kind of architecture: Ie7 offers browser tabs. This is a great feature in which you only have to open Ie7 once and you can use the same browser-engine for accessing the internet.
One of the main issues with an All-in-One (AiO) approach is that one may spoil for all. In Ie7if you are related to a site that no longer responds you will loose all your relationship if you need to abort.

Another example of an All-in-one configuration are music equipments where dissimilar devices - like a Cd-player and a tuner -- are stored in one single box. The design of such a single box is easier to streamline, but individual "best-of-breed" devices are often technically more sophisticated. In such a best-of-breed (BoB) architecture a buyer may pick to select the best o each type of device. The best Cd recorder is possibly from a dissimilar supplier than one from a supplier which offers all (in one).

Both configurations - AiO and BoB - are used in a wide area, also in organizations and systems design. The advantage of designing software and systems with a AiO-approach is that you do not have the hunt the store and buy from a "expensive" supplier and join a explication that will not perfectly match to your needs. Rather designing and developing AiO by your own society is perceived to be much easier. Administration of one improvement team is easier than managing dissimilar parties.

Awareness of such system helps your society in the improvement of stock improvement and design. This awareness is however only a first - but foremost - step in managing of systems development.

© 2007 Hans Bool

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It is always impressive to palpate a of course "slick" user interface. A truly graphical user interface (Gui) should of course be pleasant and fascinating at first sight. Not all that many years ago we were article with electronic devices with cryptic displays that had minuscule to no graphics; we just wanted the new, novel gadget to be functional.

But, as time has pushed us forward, our society has come to be well-known with, and, it is quite clear, dependent upon embedded electronic devices such as cell phones, personal assistants, and your cordial automotive dashboard. "Functional" is no longer enough.

In the world of the desktop computer it is unheard of to not have a "pretty" graphical user interface. In the world of embedded devices pretty Guis (pronounced "Gooeys") had been harder to come by. However, the end product audience, you and I, no longer accept a mediocre display on our technological wonders. (We certainly don't in our games, but that is a whole other story!)

Fortunately, some vendors in the embedded gadget market had seen that there was not only a need to help descriptive designers and engineers work more closely together in the embedded product design world, but that there was an confident merger of the two disciplines. One such company in the embedded Gui market, Tilcon, has recently introduced a new version of their Gui design system that substantially reduces the time it takes to make a expert and pretty Gui.

In the embedded graphics world there is the idea of a "virtual" interface. A display, for instance, on the dashboard of your car, might show several meters showing speed and tachometer readings, a bar graph for temperature, a range of "idiot" lights and even touch-screen controlled buttons. You are shown data in real-time as it is communicated to the display from the many microprocessors throughout the vehicle.

These entities used to be real corporeal entities, and now they are painted on the screen by the Gui system. In the Gui world these virtual objects are called "widgets." These "widgets" are painstakingly crafted by descriptive artists to appear as real as possible.

Every embedded product Gui design is finally a work of aesthetics. To sell in a competitive world, the gadget must fit into the flow of the broad product team's conceptual goals. Ordinarily the Gui team creates a "basic" widget set and then has to painstakingly work with personel artistic renderings to write code to recreate the image, or possibly to import every photo and element. By anyone process, it is no small feat.

Tilcon has elevated the efficiency of the embedded Gui design process to a new level with its modern Adobe Photoshop integration. In the Tilcon Gui system, a basic set of widgets are supplied as standard. The embedded designer plainly drags and drops the desired widgets on the screen as needed. Once the screen design is complete, the user plainly hits the export button and out pops a Photoshop file. This file creates all the layers needed by a Photoshop-based designer to begin the artistic process of "branding" and creating the desired look and feel of the end product.

The fascinating part of this process, for those of you that are well-known with Photoshop, is that every particular widget object is exported into its own "layer," and the layers are laid out in Photoshop "groups." If a "button" widget has one image when "on" and another for "off," each state will have its own layer created. This Psd file is delivered directly to the descriptive designer. The artist goes to work in parallel with the embedded Gui engineer. Every particular item can be hand crafted inside the Adobe toolset, and upon completion, the final file is delivered to the engineer, who plainly imports the new look by pushing an "import" button. Suddenly, the screen is gorgeous!

Perhaps even more importantly, the engineer has prolonged his work unimpeded using just the basic widgets. Team productivity is enhanced. product supervision is happy. The sales team will love the new expert appearance of the end result.

The implications of the time savings that this process represents to product design teams are obvious. What might not be so confident on first inspection is how rapidly a team can "re-skin" its product look, or "custom-brand" the product for its own end customers. The result: a product design team has faster access to great-looking displays, can use the same gadget for several different end customer's needs and can deliver a custom appearance for each such buyer with much greater ease and time savings. Now, that's worth seeing!

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