Heart rate indicator

Heart rate is one of many important parameters in diagnosis or sports. It is easy to calculate heart rate by sensing wrist or neck pulse. This method isn’t handy at all as it occupies your hand and mind of course. Doctors use other ways to monitor heart rate which is actually a side effect of other measurements like blood oxide level or pressure. It is actually easy to measure heart rate by using simple circuit based on IR sensor. In this case infrared sensor catches signal reflected from fingertip (different from pulsoxymeter), so no need for clip – it is enough to put a finger on top of detector. Circuit itself consists of two stages – one is a conditioning circuit which detect reflected signal changes and amplifies it to acceptable level for digital circuits. And second part is a PIC16F628A microcontroller based counter and display driver. In my opinion using clip would be more practical as pressing fingertip to sensor doesn’t seem very practical. Continue reading

A PIC16F628A breadboard module

You don’t usually see microcontroller projects in a breadboard and I’ll give you one reason why – microcontrollers require some external components that eventually consumes the prototyping space in a breadboard. This is one of the reasons why hobbyists prefers to make/test projects in a custom PCB rather than the good old breadboard. To remedy the dilemma of prototyping a PCB just to test a microcontroller circuit, R-B had this very fancy idea of making a breadboard module for a microcontroller. The module’s main part is a PIC16F628A, all the external components to make the microcontroller functional is also placed in the board – oscillator crystal, pull up resistor for the MCLR and even the reset button are already in the board. The only pins that sticks out of the module are the I/O pins and the power pins. Now people can verify microcontroller circuits without fabricating a specific board. Continue reading

Button Code – single button code entry system using PIC16F628A

Back in my elementary years I was thought how to use Morse Code – that is talking through dots and dashes. “Dot-dot-dot-dash-dash-dash-stop”. I didn’t realize it back then but Morse Code is a form of serial communication, just using a single line to convey information. Button Code runs in a similar idea, just using a single button to key in values that would normally require multiple push buttons, thus completely replacing the entire numeric keypad. The user will input a four digit code using taps to the input button. A PIC16F628A was used to detect the code pattern; it monitors the taps on the button while also giving acknowledge signals to the user  – by using blink of a LED and when the correct code sequence is entered a single pole double throw relay will be activated. The common, normally open and normally closed pins are accessible through an end block connector and can be used to switch thing on and off. It has two operating modes the first is the running mode where it waits for the user input… Continue reading

The Scrolling Text on Oscilloscope Based on PIC16F628A

Many of you here might have heard about the oscilloscope before, or maybe have frequently using them in your daily electronic project! However, have you ever used the scrolling text on oscilloscope? To be honest, it’s nothing different, except you are using the scrolling text on oscilloscope. For your information, the project is built with only one component, the Microchip PIC16F628A! You must be shocked and wondering, “Oh, is it possible to build a device with one electronic component?” Hehe, anything is possible, as long as you knew the proper ways! When you’re using the scrolling text on oscilloscope, the characters that are going to be displayed are stored in EEPROM. Normally, the first EEPROM location with 0xFF value is considered as end of each text, while the last EEPROM location (address 0x7F) contains the scrolling speed in 20mS steps. You must know that the configuration word for this application (address 0x2007) is 0x3F34. Hence, you need to place a jumper between the pins VDD and VPP, after you’ve programmed the micro via the ICSP connector. Mostly, the oscilloscope will… Continue reading

Crossbar – The Fantastic DIY 4×4 LED Matrix

If you always have the intention to build a fantastic 4×4 LED Matrix, then you might want to check out this Crossbar! Well, this Crossbar is a very easy project, especially for those who involving with LED Matrix frequently. The Crossbar is based on a PIC16F628A. Although this chip cannot directly control the 16 lines necessary for an 8×8 matrix, but it’s more than enough to control the 4×4 matrix! One frame on a 4×4 matrix is only 16 bits or equivalent to 2 bytes, while a frame for an 8×8 matrix might require 8 bytes, which is 4 times of the 4×4 matrix did! If you want this Crossbar to be viewed by everyone, then you have to figure out the way to solder the LEDs at the intersection of each one. It’s better not to use the steel to hold the LEDs, as it easily rusted and has trouble holding onto the solder. By the way, you don’t need to use the LM7805 or any capacitor, if you applied a regulated power supply onto this project. Good luck… Continue reading

Into The New Dimension World with Triangular LED Animation

Any Star Trekkies here? By the way, have you went to the cinema and watched the Star Trek, The Movie yet? No matter you’re the Star Trek’s fan or not, you will still love this Triangular LED Animation, as this stuff is very futuristic and ‘3D’ enough! For your information, this project is based on the PIC16F628A and Simple LED Animation Kit with the combination with red/green LEDs arranged in a triangle. The three sides of the triangle are fully-connected in parallel form. In this case, the PIC16F628A is controlling only six bicolor LEDs while the other 12 LEDs are individual elements. Between the triangular arrangements, it’s possible to create a large number of different animations. Hence, the animation sequence takes 10 minutes to repeat. Before you’re getting started, you should think and plan wisely about the design, especially the white board for your PCB. This step is to eliminate any unwanted consequences while you’re building this Triangular LED Animation. By the way, you need to apply a regulated power supply into the project. However, if you can’t find any… Continue reading