Electronics-Lab.com Blog

coremelt.net writes:

This is an experiment board based on the new AVR ATxmega 128A1 microcontroller from Atmel. It features some nice gimmicks like an opto coupler, a RGB LED, a microSD card slot, infra red transmitter and receiver, USB, an external SDRAM and EBI extension header as well as a rotary encoder. The board has 6mil structures and hence is not home-producible (at least for the most of us). The board aims to be a general test bed for getting familiar with the new Xmega series. It could also be used as an application board.

It started out as a community project and I am about to spread about 100 pieces of this board into the crowd. We can expect some external contributions mostly in form of example code, which is rare at the moment. Although Atmel announced the MCU well over a year ago it is now that the first models become available in small quantities. This edgy character also establishes itself when it comes to the toolchain and programming tools and costs a lot of effort.

ATxmega128a1 development board - [Link]

coremelt.net writes:

Since this is a well working low budget AVR ISP progammer (by Thomas Fischl), I offer a compact single-sided THT-SMD combined layout. The circuit is identical to the official programmer, so the original firmware can be used with this board. This programmer is supported by avrdude. One of the main features is that the low speed USB protocol stack is realized directly with the used AVR controller, which makes this programmer a low budget one, about 5EUR material costs. Notice however that this programmer cannot be used with 3V3 systems without an additional level shifter.

Alternative board for USBasp AVR ISP programmer - [Link]

dangerousprototypes.com writes:

We’ve seen some pretty cool projects that use blinking lights on a PC monitor to transfer data to a microcontroller. We did a little research, and here are some example projects we’ve found.

This project uses two photo transistors to read a bar code from the monitor. One handles the clock, while the other has the data. The data is read as the clock changes from black to white.

Here is the same project with a different variation of the transmission system. Instead of bar codes, two small rectangles flash to give the data and clock signals.

A more advanced setup is used by SparkFun’s bracelet kit, and the Blinky POV. Here only one flashing square is used to blink out the data, while the timing is handled onboard the uC.

You can find the blinking transfer software for the Blinky POV here, and for the bracelet kit here.

Cheap light-based PC to microcontroller communication - [Link]

The Little Wire is an open source AVR programmer that’s packed full of features:

• An AVR programer
• Four digital GPIO pins
• ADC with 10 bit resolution
• Two parallel hardware PWM outputs
• An USB interface
• A SPI interface

Little Wire – minimal AVR programmer and more - [Link]

Christopher built an ATTiny85 development board. It has all the microcontroller pins broken out to a 2×4 dual row pinheader, a power indicator LED, and a reset button as well. [via]

DIY ATTiny85 Development Board - [Link]

This is a development board for the PIC18F2550, I designed this board inspired by the TP-2550 development board by Giovanni Lafebre (site is in Spanish). Main difference between the original and my design is the size, mine is 10×8 cm, so it has less elements. This is because I created this board using the free version of Eagle, so I adjusted to its restrictions. [via]

Eaglefree18f2550 features:

• 8 LEDs.
• 4 push buttons with pull-down 220Ω resistors.
• 2 potentiometers.
• 1 relay with an active LED indicator. For using the relay, you must provide an external power supply.
• 1 H bridge.
• 1 barrel connector for H bridge power supply.
• The board can be supplied from the USB or from an external supply (jumper selectable).
• 5V regulator onboard.
• ICSP port for PIC programming.
• Jumper for enabling/disabling programmer voltage. This allows for the programmer to be powered from the board supply, so we can have the programmer plugged to the board all the time.

Eaglefree PIC18F2550 development board - [Link]

dangerousprototypes.com writes:

Here is a breakout board for the PIC16F87X microcontrollers. It has a onboard 5V power supply, a 20MHz crystal, and a reset button, while all the IO pins have been broken out into a single row header, so its easy to interface with a breadboard. The UART and ICSP programing header have been broken out on the top of the board.

As  a bonus this board has a RS-232 level translator daughter board for easier interface with a computer serial port. The board can be built with the daughter board attached or without it.

nedoCPU-16: PIC16F87X breakout board - [via]

dangerousprototypes.com writes:

A new internet controlled lighting project called SplashLight is being developed. It has 4 relays to turn lights on and off, and 3 PWM outputs to drive RGB LEDs. The core of the project is a Cortex M3 uC with an Ethernet PHY/MAC from Texas Instruments.

The project includes iPhone, Android, and web applications to control the board over the web. It looks like the PCB and schematic files will be made available in the future, but the license is still unannounced. Might be ripe for a remake.

Network controlled relays & 3 channel PWM - [Link]

This is a DIY USB programer for Altera FPGAs. It only uses a PIC uC and a few discrete components to provide a JTAG interface with a FPGA. Somun found it on a Japanese site (machine translation), and with the help of Google Translate he built one for himself.

There are two versions available. The older one pictured above uses a PIC18f2550 chip, while the newer one uses a cheaper PIC18F14K50. If anyone is interested drop a comment in the forum and Somun will provide the eagle files for his build. [via]

FPGACheap DIY Altera FPGA USB programmer - [Link]

PID is implemented when a precise way is needed to drive an external device that provides feedback. Heaters with temperature sensors, and servo motors are examples where PID is used.

This app note by Microchip gives instructions how to implement PID control in PIC18 projects. Basic terms are explained inside the document as well as algorithm flow charts to understand how PID is implemented. Microchip has also provided assembler source code to go with this app note. [via]

App note: Implementing PID on PIC18 microcontrollers - [Link]