Tag Archives: open source hardware

Upcoming events: OHS, TAPR DCC, NYMF

OSHW summit goodie bag
photo credit: adafruit

There are three major events of interest to open source hardware and makery folks this month:

I’ll be at OHS and TAPR, but have to skip the NY Maker Faire this year.  I imagine that far fewer folks from OHS will be attending NYMF now that those events are no longer co-located.

Sorry NYMF, but I can’t turn down an excuse to visit my friends in Harvard square.

Quick look at the Blinken Button

Here’s a quick look at the new Blinken Button kit from Interactive Matter.

If you want to try your hand at surface mount soldering, this is a fun project that can be completed in a couple hours with a decent soldering iron and a pair of tweezers.  The instructions aren’t perfect (I had to short across the PCB pads for D1 and D2 to get my programmer to talk to the AVR, and at the moment you have to install Eclipse to compile the hex file) but I am confident that these minor issues will be fixed shortly!

Introducing the AVR HV Rescue Shield

AVR HV Rescue Shield with ATmega168 target

This all started last year, when I was playing with an ATmega168 microcontroller and did something silly.  I programmed the RSTDISBL fuse bit, which effectively makes it impossible to reflash the chip using an ordinary (serial) programmer.

Instead of giving up and throwing out the “dead” chip,  I decided to try to revive it using an obscure high voltage parallel programming mode that isn’t supported by most AVR programmers.  Armed with my Arduino and the ATmega168 datasheet, I quickly designed and constructed a programmer using parts I already had on my workbench.

A few hours later, I tested my new programmer and it worked!  I revived my “dead” AVR by using spare parts and a few lines of Arduino code.  That week I published the schematics and Arduino sketch to the site and called it my Arduino-based AVR High Voltage Programmer.

The response was overwhelming.  Since I first posted the design, many people have built their own and used it to fix their “dead” AVR microcontrollers by restoring the fuse bits to sane values.  I even received several requests for a PCB and/or kit based on the design, which got me thinking…

Today I’m proud to introduce:

The AVR HV Rescue Shield

The AVR HV Rescue Shield is a high voltage parallel mode fuse programmer for Atmel AVR microcontrollers.

It currently supports the ATmega48/88/168/328 series and the ATtiny2313.  The Rescue Shield does everything my original AVR High Voltage Programmer does, and a lot more.  I think the new features make this a really useful tool for anyone working with AVR microcontrollers.

New features include:

  • Custom 2-layer PCB with silkscreen and soldermask.  No more hacking and modifying perfboards to fit Arduino’s nonstandard pin spacing!
  • Onboard 12V DC-DC boost converter eliminates the need for an external 12V power supply
  • Support for two of the most common families of AVR microcontrollers, the ATmega48/88/168 and ATtiny2313
  • Support for programming the extended fuse (EFUSE) byte.
  • A new interactive mode, where desired fuses can be entered using the Arduino’s serial port.
  • Separate Ready and Burn indicators
  • Protection resistors on every single data, control, and supply line to the target AVR, meaning that your Arduino and AVR should survive any mishaps during programming, including inserting the AVR backwards or off by 1 pin.

I spent considerable time testing each new feature and documenting the Arduino sketch.  I hope that you’ll find that the finished product was worth the wait!

Ordering instructions:

To purchase bare PCBs and kits, head over to the AVR HV Rescue Shield product page.

rescue-burn-ready_scaled

rescue-mightyohm_scaled