September 17th, 2010

ATmega168 external interrupts

atmega168 external interrupts

Daniel Garcia from Protostack, the guy who sent us an ATmega8 dev board a while ago for review, wrote a tutorial on how to use the atmega168 external interrupts. The tutorial is quite nice and you should know the way around external interrupts at the end of it. The general principles apply to other AVR microcontrollers, but the specific vary greatly. Remember that we also have a tutorial about I/O handling on their dev board.

ATmega168 external interrupts: [Link]

protostack AVR 28 pin board

You may recall, almost a year ago we did a review of Protostack’s ATmega8 development kit. You can read the original review here. Well it turns out that they have been busily churning out new versions of this board, with version 1.4 being released, just the other week. This version has got many improvements over the one we reviewed. Some of the recent improvements include a power supply block for L7805 and the like, a 23 pin ISP port and a section for dual row headers or IDC connectors. The board still retains the same great features that we saw in version 1, like the large breadboard style prototyping area and the power busses that are routed throughout. It is available by itself or as part of an ATmega8 or ATMega168 development kit. With both kits being under $20 and the board itself under $10, it is still quite affordable.

Programmable Remote Control for Nikon

If you’re an amateur photographer and own an entry-level Nikon DSLR, you might be dissatisfied with the lack of certain features these models have, which can be quite disappointing since high-end cameras are pretty expensive. But there is something that can be done. The cameras have an infrared sensor that can be utilized with great success using a remote control, so you are able to take pictures and control your camera from afar. And here’s where the programmable remote control for Nikon comes along, enhancing the capabilities of your camera.

This project is a small remote control based on the Atmega168/328 microcontroller from Atmel. It also has a bunch of 3mm LEDs (one of them is the power LED, the rest are for different programs for the camera), capacitors, resistors, 3 switches, a battery holder and an IR LED. The device ends up using all GPIO pins of the MCU (you can find detailed schematics and a complete parts list in the link).

The code is available for reading and download and is neatly commented so you can understand what it actually does. The code makes use of Cibo Mahto’s Nikon Library. Gerber files and Eagle files are also available for download. A nice device to have when taking difficult shots with your DSLR, the programmable remote control for Nikon can be a great addition to your photo gear, helping you make great use of your DSLR.

Programmable Remote Control for Nikon: [Link]

June 5th, 2009

DIY Wifi Radio

DIY WiFi Radio

You like listening to radio and your favourite stations use Internet broadcasting? Or you’re sick of commercials between songs or the radio man spoiling the song with some announcement? Here is an award worthy project for you. With this wifi radio you have wireless connectivity to the Internet so you have a huge variety of radio stations to tune in, mp3 decoding, 44.1kHz 16 bit stereo audio, 4W amplifier with two 4 inch speakers, LCD display all this in a very nice vintage looking compact case. Total cost under 100$.

Asus WL-520GU was the choice for the wireless router. For under 50$ it’s a good platform for an embedded Linux system, its only shortcoming would be that it lacks built-in audio. This problem was solved with an USB audio adapter SYBA SD-CM-UAUD for 8$. Notice however the Asus router only supports USB 1.1 which is enough for audio, WL-500GP v2 can be used for USB 2.0. The router has a Broadcom BCM5354KFBG SoC CPU running at 200Mhz, 4MB flash and 16MB SRAM.

The most important part of the project is hacking the WL-520GU. Since it is just a router you will need to write new firmware to turn in into a wifi radio. This is done on the serial port which is pretty easy to access. The chosen open source Linux distribution that supports this router was OpenWRT. In the link you will find a precompiled image, thanks to the designer and builder of this project.

The LCD interface communicates with the WL-520GU by serial using ATmega168 microcontroller. On one of the analog inputs of the Atmel a potentiometer is connected and rotating the pot will make the radio jump to next station.

This is really an advanced project and i just love how it turned out. Lots of information on how to build one yourself is available in the link and I’m sure if you decide to go for it you will not regret it.

DIY Wifi Radio: [Link]

April 30th, 2009

Arduino Board Clone

Arduino board clone

Arduino based projects are very popular, because of its versatility, ease of operation and pretty large amount of projects available to be put into practice. This being said it’s not unexpected to see clones being made like the Coreduino.

Named like this because it uses the core of the Arduino board, the ATmega168 microcontroller and its oscillator components 16Mhz Xtal and the two 15pF capacitors. Coreduino’s PCB is smaller and can be easily connected to a breadboard. There are soldering bridges that let you power the board from ISP or USB. The programmers were built on separate PCBs and this way you can use the same programmer for many Coreduino boards. USB and Serial programmers are presented.

The USB programmer uses a FT232RL chip to convert data from USB to serial and send it to the ATmega. It can also power your Coreduino board and you can select the logic level to either 3.3V or 5V. The serial programmer has two level shifters made with discrete components and you can have RTS or DTR line to reset the Coreduino but you can not power the board with it.

In the project you will find all schematics and PCB layouts, everything you need to get it done.

Arduino Board Clone: [Link]

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