Category Archives: Products


I/O Experimenter Board (PCB version)

Most embedded projects require the same common stuff, basically I/O devices such as switches, LEDs, LCD display, buzzer, etc. Connecting these things on a breadboard for prototyping every new project is time consuming and boring. Recently, I have designed a general purpose I/O experimenter board that will not only reduce the prototyping time for a new project but also free up plenty of space on the breadboard.

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Assembly instructions for Easy Pulse kit

Assembling Easy Pulse kit is pretty simple and straightforward. There are two versions of PCBs which are mostly the same. In the second version the J1 connector has 5 pins instead of 4. I have added an additional VCC pin next to the EN pin. This would allow users to test the board quickly after being assembled. You can activate the sensor by simply placing a jumper between the EN and VCC pins, and the board is ready for operation. While soldering the parts, start with low profile components such as resistors and capacitors. This makes overall soldering process easier.

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Introducing Easy Pulse: A DIY photoplethysmographic sensor for measuring heart rate

When I first built the Heart rate measurement through fingertip project, the infrared LED and photodiode used for finger photoplethysmography were actually from salvaged parts, and therefore, I could not provide specifications for them in the article. As a result of that it takes quite a bit of time to replicate that project with a different set of IR LED and photodiode as the values of the current limiting and biasing resistors may have to be changed for the new sensor to work properly. Today, I am going to talk about a revised version of the same project but with all the

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More MAX7219 based serial seven segment LED displays are available now!

Due to high demand of the MAX7219 based serial 4-digit seven segment LED displays, I recently ordered more PCBs for this. You can now order a complete kit for $11.99 and an assembled module for $13.99. Both prices include free shipping within the continental United States. The display is based on the MAX7219 driver chip that supports 3-wire SPI interface. You can find an interfacing example for PIC12F683 microcontroller here. The example code is written in C and therefore, it can be easily implemented to any other microcontroller family. This display module is available for purchase as a kit. The

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Dual 4-digit seven segment LED display with SPI interface

This project is an extension of my previous MAX7219 based SPI seven segment LED display module. The new display features eight 7-segment displays arranged in two rows of four digits. The on-board MAX7219 driver enables you to easily add eight 7-segment LED displays to your project using only 3 I/O pins of microcontroller. The major advantage of using this board is the time-division multiplexing operations required for continuous refreshing of the display digits are performed by the MAX7219 chip, thereby keeping the microcontroller free for doing other pressing tasks. It is suitable for displaying two variable values simultaneously in a

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