Showing an AVR Programmer Who’s Boss

[Bogdan] makes a good point. When you use a dev board you get programming, debugging, power sourcing, and usually a UART. When you go to the trouble of hooking up a programmer why don’t you get the same thing? Astutely, he points out that all you usually get with programmers is programming. So he set out to add features to the hardware he uses to program XMEGA.

The first part of the trick hinges on his use of PDI programming. This is slightly different from ISP programming. Both use a six-pin connector cable but with PDI two of these pins are unused. He took this opportunity to reroute the chip’s TX and RX pins through the cable, which now gives him an avenue to use a UART-to-USB adapter without adding any cables to his target board. Rather than add a second USB cable he rolled a USB hub into the mix. An LM1117 regulates the 5V USB rail down to 3.3V as a source for the target board.

The programmer being used is an Atmel ICE. As you might imagine he didn’t want to make permanent alterations to it. His modifications are all handled externally, with one IDC cable connecting the programmer to his added circuitry and another headed off to the target board. For now he’s jumpering RX/TX to the programming header but plans to route the signals on future PCBs.

Light Controller Goes Overboard for Halloween


Yep, we said it. This Halloween decoration goes way overboard… and we love it! Not only does [Shelby Merrick] put on an incredible sound and light show for the neighborhood, but he keeps us happy by posting all the details for the lighting controller he designed. He calls the creation FloodBrain as it’s switching a set of flood lights to achieve the effects seen above. But for the full experience you’ll want to watch the demo videos below as well.

He needed a way to switch twelve RGB flood lights which pull 10 Watts. His controller was designed to communicate with them via RS485, with an AVR Xmega8E5 controlling the system. We like it that he included some images of the manufacturing process, using a stencil for solder paste before placing components for reflow.

The floodlights themselves are also an interesting hack. To get what he wanted at the best price he picked up 10W white LED flood lights for about eight bucks a piece, then swapped out the LED itself for an RGB version (same wattage) using the same heat sink and case.

More often that not we see this type of system controlling Christmas lights. [Shelby] mentions that he did get help from Christmas light controller forum We also think he should have no problem repurposing the controller for that type of application.

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2013 LayerOne badge hacking contest winner


[Dynotronix] wrote in to share the news that he won the 2013 LayerOne badge hacking contest. In addition to the good news he included a description of his badge hack.

We got a good look at the hardware included on the badge several days ago. You may remember that it’s outfitted with footprints for 48 LEDs around the perimeter which are driven by two ICs. Looking at the image above it’s hard to miss the fact that [Dyno] didn’t populate any of that. He went right for the power of the XMEGA processor to analyze and generate signals.

But what specifically can you do with the signal this thing generates? Turns out a rather simple circuit can make it into a transmitter. [Dyno] concedes that it’s a remarkably finicky setup, but just a few components on a scrap of copper clad turned this into an FM transmitter. Check out the video where you can hear the sweeping alarm-type sounds pushed to an FM radio via his voltage controlled oscillator circuit which has a range of about fifteen feet.

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Programming the XMEGA with an ISP

Atmel’s XMEGA series of microcontrollers are neat little pieces of hardware; with a very fast clock, a ton of IO, USB, and up to 8 UART ports, these neat little chips serve as a nice bridge between AVRs and PICs and the very powerful ARM chips coming out on the market. Unfortunately, the XMEGAs don’t use the extremely common ISP programming header found on just about every AVR dev board making them a bear to program. [Szu] over in Poland came up with a very easy way to program these chips, all while using the programming hardware you already have on hand.

[Szu]’s build uses a few resistors and diodes to break out a USBASP connection to the XMEGA’s PDI interface. On the software side of things, [Szu] wrote an update to the USBASP firmware to allow it to program PDI devices, and also has a patch for AVRdude to allow uploading firmware from the command line.

A very cool build, and one that allows for very, very powerful devices that build on the AVR code you’ve already written.

CheapStat: an open-source potentiostat

A commercial potentiostat can cost several thousand dollars, but the CheapStat is an open source project that makes it possible to build your own at a tiny fraction of that cost. It is possible to build one for less than $80, breaking down the cost barrier faced by many labs that would like to have this test hardware.

A potentiostat is used to measure electrochemical properties. To give you a few examples of what it can do, the hardware can measure arsenic levels in water, Vitamin C concentration in orange juice, Acetaminophen concentrations in over-the-counter medications, and a bunch of other less easily explained tests having to do with chemical compounds and DNA.

The device makes use of an Atmel XMEGA microcontroller and connects to a computer via USB. A Java program grabs that data from the hardware displaying test results on your choice of computer platforms. If you’re looking for all the gory details you won’t be disappointed by their journal paper.

Ever wonder where cool interactive museum exhibits come from?

[Victor’s] girlfriend works at a museum and enlisted his expertise in designing an interactive detective game for kids visiting the museum. The vision was for the kids to discover phone numbers that they could call for clues. Originally he planned to display the clues on a character LCD, but obviously it’s much neater to hear the clues in the handset of the phone.

Quickly switching gears, [Victor] dropped the ATtiny2313 and started over with an Xmega chip — in fact, it was our recent Xmega post that inspired him to document his project. The microcontroller is responsible for a lot of goings-on. It scans the key matrix for inputs, simulates the DTMF touch tones, reads audio files from a FAT file system on an SD card, and plays them back over the hand set’s speaker. Since most of the hardware is already built into the phones, it was not hard to fit his add-ons inside the case. A simple audio amplifier circuit joins the microcontroller, which is patched into the rows and columns of the keyboard. Take a gander at the video after the break to see the device in action.

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Regarding Atmel’s Xmega chips

A few years back Atmel announced a new line of chips, the XMega series. We see the name bouncing around here and there, but when [Michael Kleinigger] mentioned that he’s seen very few project using these chips we realized that not only is he right, but we know next to nothing about them. Just give his XMega review post a whirl and you’ll be up to speed in no time.

He compares an XMega128A1 side-by-side with an ATmega1280. For those that abhor reading paragraphs full of words, there’s a table that can give you the quick facts like how the XMega costs less and runs faster. But we know from past discussions (like the one on PWM) that [Mike] knows his stuff so the whole thing’s worth a read. He’ll lead you through the programming tool chain (which hasn’t changed), a bit about the new event system, and then finish with a demo program on the Xplained development board.