Category Archives: Embedded Lab Projects


LM386 based stereo audio amplifier with digital volume control

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Due to its simplicity (requires minimum external components) and high availability, LM386 is very popular among hobbyists for use in low-voltage audio amplification applications. Most of the time a potentiometer is used at the input side of LM386 to provide a volume control in the output speaker. The potentiometer does not control the gain of the amplifier itself, but it creates a voltage divider network at the input, which in fact controls the fraction of the audio signal that is fed to the amplifier. This project is about a stereo audio amplifier using two LM386 ICs with digital volume control for both

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Experimenter’s board for enhanced mid-range PIC microcontrollers (PIC16F1827 and PIC16F1847)

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The PIC16F628A has always been my first choice for microcontroller-based projects. It is simple, inexpensive, and easily available. Due to its compact size (18 pins) it occupies lesser space on the circuit board, and meanwhile, it is powerful enough to serve most of a hobbyist’s needs. It is a very well accepted successor of the classic PIC16x84, and therefore, the tons of resources available for PIC16x84 on the internet and books can also be used for PIC16F628A. Last month, Microchip Technology Inc. announced the latest addition to its Enhanced Mid-Range core 8-bit PIC® microcontroller (MCU) family by introducing PIC16F(LF)1847. When

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Humidity and temperature measurements with Sensirion’s SHT1x/SHT7x sensors (Part 2)

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In Part 1 of this tutorial, we discussed about Sensirion’s SHT1x and SHT7x series of humidity sensors, their interface specifications, the communication protocol used for transferring data in and out of the sensor, and the equations to convert their digital outputs to actual physical quantities. These sensors are capable of measuring temperature along with relative humidity and provide outputs in fully-calibrated digital words. We will now see how a PIC microcontroller can be programmed to communicate with these sensors, read the temperature and relative humidity data, and display the information on a character LCD.

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How to make a contact-less digital tachometer using IR-light reflection technique

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Tachometer is a device that measures the rotational speed of any shaft or disc. The unit of the measurement is usually revolutions per minute or RPM. The traditional method of measuring RPM of a rotating shaft was based on velocity feedback concept where a dc generator is hooked to the rotating shaft so that the voltage induced across the generator’s terminals is proportional to the speed of the shaft. Today, we are going to make a digital tachometer based on a PIC microcontroller that requires no physical contact with the rotating shaft to measure its rotational speed. The physical contact

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A Beginner’s data logger project using PIC12F683 microcontroller

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It is a very simple data logger project based on PIC12F683 microcontroller. The microcontroller reads temperature values from a temperature sensor on a regular interval basis and stores them into its internal EEPROM memory. The recorded temperatures can be later transferred to a PC through serial interface. I originally published this project on electronics-lab.com last summer. I thought this could be a very good learning project for beginners, and so I am posting it here for Embedded Lab’s readers too.

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