This is a complete mobile MP3 player and first mp3-player with ATmega8 and Nokia 6100 color display.
An demo firmware and gerber file for board will be available soon.
This player has capability to play wav and mp3 files and view BMP files on 8 or 24 bits/pixel from a MicroSD card with maximum capacity 2GB, the format of the SD is FAT32 with clusters from 512 Bytes to 32768Bytes, the filesystem has no limits in number of directories and files.
For future i want to adapting the SD driver for SDHC because the filesystem is designed to use all capacity of fat32 ( 2TB in 512Bytes/sector)
List of features:
Play Wav and MP3 Files because the VS1011a only this files is capable to decode( but for future in this project i want to include the VS1053 chip to play more file formats.
View Bitmap files on 8Bit and 24 bit/pixel
This project is in asm language and my 100% own libraries
DiY: most tiny MP3 player with ATmega8 VS1011a and Nokia6100 Display - [Link]
Microchips – are indeed can be considered a black box – as long as it’s working you normally don’t look inside.
But what if you want to?
Today we’ll show how to “open” chips and what’s inside.
How to «open» microchip and what’s inside? - [Link]
Andrea Biffi build a nice vertical nixie clock using ATmega8 mcu. He writes:
After the success of my first nixie clock made out from a rosewood block, I decided to lose no time and to carry on with the next one. As some of you guys already know, or imagine, lately I’m indeed a little bit addicted to nixie-mania. I’ve bought many nixie tubes on eBay, and I experienced in electronics so to build my own high voltage power supply and then the ultimate nixie clock circuit. Digits for this clock are nice rounded and fully transparent IN-4 tubes, the same I used in the first model, but as I previously announced, I aligned them vertically, so to read from top to bottom hours, minutes, and seconds. Indeed you will see the undeniable influence of Max Pierson’s vertical clock. I guide you now through the full process to make your own unique nixie clock.
Vintage style nixie wall clock - [Link]
Hemal Chevli blogged about his transistor tester project:
It has mega-8 as the brain, lcd to show specs of the transistor like which pin is which, what type of transistor it is eg NPN,PNP, N-MOSFET,P-MOSFET, etc., many components can be tested like different types of transistor, diodes, resistors etc, the good thing about this is that it also shows which leg is which, no need to open the data sheet
Transistor tester project - [Link]
Scott Harden writes:
In an effort to resume previous work [A, B, C, D] on developing a crystal oven for radio frequency transmitter / receiver stabilization purposes, the first step for me was to create a device to accurately measure and log temperature. I did this with common, cheap components, and the output is saved to the computer (over 1,000 readings a second). Briefly, I use a LM335 precision temperature sensor ($0.70 on mouser) which outputs voltage with respect to temperature.
Precision temperature measurement - [Link]
Hercules Trapierakis writes:
This is a copy paste tool of George’s Homemade Soldering Station but with some improvements and not with a PIC but with an AVR ATMEGA8 uC. I have changed the way that the information is displayed also you can adjust the P I D values and it has a safe mode option – that it will turn off the soldering iron if it is not used for a certain amount of time.
Homemade Soldering Station - [Link]
This is a simple use of internal ADC of AVR atmega8. Voltage is measured directly with help of resistor divider and amperes is calculated based on the voltage drop in a low resistance power resistor.
Atmega8 based Volt – Ampere meter - [Link]
Charalampos Andrianakis writes:
Two years ago i modified a scanner replacing its mechanism and all the internal electronics with UV lamps converting it to an UV exposure box for PCB prototyping. By the need of making my life easier and not waiting for the pcb to be exposured i designed an AVR timer to automatic switch off the lamps after 1 minute of exposure which was much enough for the PCBs. Here is the circuit
This was one of my first completed projects from design to production. As you can see the scheme isn’t that good and there have been by passed some capacitors at the power supply. But the circuit works with no problem.
AVR Switch Timer - [Link]
I designed this version in the need of a thermometer for my room, built in a small pack and easy to control. The hardware is designed on a way so that the pcb can be wall mounted. At the top side of the device the PCB extents giving space for two keyhole type holes which are able to keep the device mounted on the wall. The LCD display plugs at the front side of the PCB, covering all the electronic components and giving a compact design view. The user can interact with the device using the left side switch button. The design includes a 6-pin header which gives connectivity for UART (RX,TX,GND) and for the external sensor DHT-11 (VCC,GND,DATA). Also there is an ISP-6 pin header which gives the option of on board programming. Finally there is an optional Bluetooth plug on the back side connected with AVRs UART for possible communication to other devices like mobile phones, home automation devices, pc’s or whatever you imagine.
The code is written in C and is well performed in a readable way so anybody can read and modify it. For the LCD driving i have used Peter Fleury’s library.
AVR Atmega8 and DHT-11 Thermometer V2.0 - [Link]
After our recent post about the commercial semi-conductor tester we started a discussion about building a similar open source project. What came up is this AVR based transistor tester (machine translation) by Markus.
It’s built around an ATmega8 IC that interfaces with a standard HD44780 16×2 character LCD. The circuit that does the testing is simplicity itself. Three pairs of resistors are connected to 6 pins of the microcontroller, and each pair is connected on the other end to one of the transistor pins.
The theory of operation is also relatively simple. The microcontroller cycles through different patterns on its output pins until a recognizable pattern is read on its input pins. It supports a very large range of devices:
- NPN and PNP bipolar junction transistors.
- P and N channel, enhanced and D type mosfet transistors.
- P and N channel JFET transistors.
- Common anode and common cathode dual diodes.
- Two diodes in connected in anti-parallel or series configuration.
- Single diode.
AVR-based transitor tester - [Link]