Electronics-Lab.com Blog

A common challenge when working with embedded systems is keeping track of real time. Luckily, most microcontrollers have timers that can be used with a precision quartz crystal — already present for the CPU clock — to keep track of real time. In this video tutorial, we show how you can use the timer interrupts on an ATMega168 chip to make a simple timer. Building off of this, it is possible to make your own reasonably accurate alarm clock, create systems to perform timed automated tasks, or create a multitude of other projects.

Crystal Real Time Clock - [Link]

Rob writes that he’s created a custom Arduino AVR library for EAGLE that lets you easily integrate Atmel’s ATMEGA168 and ATMEGA8 microcontrollers into your designs. You can download this library from the link below. [via]

Arduino AVR library for EAGLE - [Link]

Ladyada writes:

Running out of space in your big Arduino project? Good news! Finally, after months of backorders, one can now buy the latest improvement to the ‘ATmega8′ line of chips: the ATmega328′s.The ’328 has 32K of flash, and 2K of SRAM. Basically its got the capacity of an ATmega32 but in a slimmer package. These chips are notable for their ability to drop-in replace the ATmega168. So that means if you have an Arduino or compatible clone, it is a easy 2 minute swap.

If you have an Adafruit wave shield or GPS/datalogging shield, and you’re annoyed that the FAT16 libraries eats up so much flash and RAM, upgrading will definitely fix the problem.

I’ve merged my previous updates to the Arduino bootloader to the most recent release and also fixed 2 annoying bugs that have prevailed this long. (1. the missing signature bytes when using the bootloader directly and 2. the broken EEPROM code). Download the ’328-compatible bootloader files here.

There are 250 preprogrammed chips are in the Adafruit webshop or you can get blank chips from Mouser (but be warned that they’re backordered till mid-December)

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Upgrade your Arduino projects - [Link]

This device monitors household power usage and logs it to an SD card. A simple analog front-end amplifies the signals from voltage and current detectors and an ATmega168 microcontroller computes the power consumption using the formula P=V*I. The voltage and current are each sampled at 9615 Hz so the integration should be fairly accurate even for highly non-sinusoidal loads such as computers or fluorescent bulbs. A graphical LCD shows the power usage as a strip chart and can also act as an oscilloscope to display the voltage and current waveforms. The current is amplified in three stages (1x, 10x, and 100x) so that different gains can be used giving accurate readings for both high and low power usage. [via]

An AVR-based power usage logger - [Link]

If you’ve got an Arduino project that you want to take one step beyond a temporary breadboard, but don’t want the hassle and expense of creating a custom PCB, Protoduino is for you. In a carefully designed general purpose PCB, all IO pins are exposed, and there’s plenty of room for additional components including another 20 pins worth of DIP. The board is designed for easy customization — traces can be cut to give additional flexibility, and unneeded parts of the board can be trimmed away.

Protoduino — trimmable, solderable, standalone prototype board for Arduino / ATMEGA8/168 – [Link]

This decoder is fed by a RDS demodulator IC (or tuner) which has RDDA (data signal) and RDCL (clock signal) outputs.The microcontrolller is an Atmega168 clocked on the external 4.332MHz crystal from the RDS demodulator. TDA7330B RDS demodulator IC from STMicroelectronics to be used in this project. The TDA7330B is connected to the Atmega168 with RDDA connected to PD4 (on PORTD) and RDCL to INT0 (PD2). [via]

Atmega168 RDS decoder - [Link]

This is versatile development board for AVR microcontrollers ATmega48/88/168. It is good for testing and debugging embedded programs. It has many built-in peripheries connected to microcontroller so you can use them without soldering. ATmega microcontrollers are produced by ATMEL and they include a lot of features: I/O, Timers, PWM generators, ADC, RS232, TWI, SPI, Analog Comparator, Oscillator, EEPROM These microcontrollers are very versatile, easy to program and easy to use. This is the reason why I like these microcontrollers and why I decided to make development board for them.

ATmega48/88/168 Development Board - [Link]

This is a weather station with a build-in webserver. The system is modular design you can either build a pure Ethernet weather station or an Ethenet weather station with an additional local LCD display.The weather station has two temperature sensors(LM335) and one MPX4115A which an absolute air pressure sensor from Motorola/Freescale both sensors controled by atmega88/168.

Data Acquisition System - [Link]

This instructable will show you how to create a multifunction platform with a thermometer, chronograph (count up timer), count down timer, and light display. It is also intended to be a platform for other analog sensors or any other functions you can think of. Project is based on Atmega168 microcontroller. Information is displayed on dual 7 segment LED display.

Multifunction Digital Thermometer - [Link]

Rebecca Stern has a cool project sensing “squeeze” she writes -

I’m researching squeeze sensing as a mode of tactile interface. Here I will cover the process of developing a squeezeable sensor and the firmware/software concerns associated with interpreting the data from the sensor. This fulfills the “sensor project” for my class called Computational Principles in Media Arts taught in AME at ASU by Todd Ingalls and Hari Sundaram.First off, how do we sense “squeeze?” People squeeze all kinds of things: lemons, steering wheels, loved ones, toothpaste and other toiletries, pimples, stress balls, hand exercisers. I would like to focus on the latter two, which provide a therapeutic activity for those with Repetitive Strain Injury (RSI). Using flex sensors arranged in a certain pattern on a spherical object, in this case a rubber dog toy, one can capture whenever the ball is squeezed.

Sensing squeeze - [Link]

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