Noise Generator Ported To Run On Small AVR, Also Arduino Compatible

August 8, 2011 by Mike Szczys 12 Comments

Feeling a bit left out because he didn’t have a PICAXE on hand, [Rob Miles] decided to port the Luna Mod code so that it would work on an AVR chip. He chose to build his around an ATtiny45, but also mentions that this is Arduino compatible.

This case layout is a bit different from the original Make version, but we like this look just a bit better. It might not satisfy your need for that hipster looking enclosure, but the repurposed macadamia nut box looks seems it was built for this purpose. Take a look as the video after the break to see the final product and hear it spewing newly composed cacophony. [Rob] is sharing the sketch as a dropbox file but we’ve also included our own hosted link after the break in case is stops working.

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AVR Programmer Modelled After The MkII – Uses LUFA

July 30, 2011 by Mike Szczys 20 Comments

Here’s a new option for building your own AVR programmer. It’s called the MkII Slim and the diminutive size makes it live up to its name. The design is rather spartan, using just three chips; a voltage regulator, a MAX3002 level converter, and an Atmel AT90USB162 as the main microcontroller. This chip has a built-in USB module, foregoing the need for a separate FTDI chip.

The firmware is built on the Lightweight USB Framework for AVRs (LUFA). This is a USB stack implementation originally called MyUSB that was developed by [Dean Camera]. Regular lurkers over at the AVRfreaks forums will recognize [Dean’s] name, or his handle [abcminiuser] as a source for many of the high quality AVR tutorials found there. But we digress.

The programmer offers all the features you’d want in an In-System Programmer. It can easily be reflashed with future updates thanks to the bootloader running on the chip. There’s jumper-selectable power options, and it can program targets running at 3.3V or 5v. The full development package including code and artwork is available for download at the site linked above. For your convenience we’ve embedded the schematic after the break.

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A Study In AVR Power Saving Techniques

July 26, 2011 by Mike Nathan 88 Comments

amtel_avr

[Scott] found the iCufflinks from Adafruit Industries pretty interesting, but he thought that the stated run time of 24 hours was a bit short. He figured he could improve the product’s power consumption at least a little bit, to improve the overall battery life.

From their schematics, he placed an order for parts and built two identical iCufflink mock-ups side by side – one running their code and one running his. He took baseline current draw measurements, then got busy slimming down the cufflinks’ software. It had been 20 years since he touched assembly, and he has never written it for an AVR, but judging by his work he’s not rusty in the least.

He slowed the ATtiny’s clock down and tweaked a few other settings for a savings of 53μA, but the real improvements came via a fairly simple fix. The original code called for the processor to institute a counting loop to sleep, which he found to be very wasteful. Instead, he chose to put the processor in an idle state, using the chip’s watchdog timer to wake it when it was time to pulse the LED. The power savings from this change alone was a whopping 261μA!

When he was said and done, the changes save about 315μA of current draw, and should allow the cufflinks to run for up to 38 hours without swapping batteries. In [Scott’s] opinion, a nearly 60% improvement in battery life is pretty good for a day’s work, and we’re inclined to agree.

Cheap Voice-controlled Lighting

July 15, 2011 by Mike Nathan 9 Comments

voice_controlled_home_automation_board

Voice-controlled home automation doesn’t have to be wildly expensive if you have a little bit of time and some know-how to do the job yourself. [jjshortcut] wanted to control the lighting in his room without using physical switches. On his blog, he describes how he did it without spending a ton of money.

He picked up a VRBot speech recognition module on eBay, which is an easy way to get your feet wet with voice control. The device has a bunch of built-in speaker independent commands, as well as the ability to record up to 32 custom triggers. Rather than mess with mains voltage and build his own light relays, he purchased a simple set of wireless light switches and began hacking.

He spent some time sniffing the wireless communications protocol to figure out how the lights were triggered, then he replicated that functionality using an AVR and a cheap 433 MHz module.

The system seems to work quite well despite how cheaply he was able to put it together. Stick around to see a quick video of his voice recognition system in action.

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Hardware XOR For Output Pins On AVR Microcontrollers

July 9, 2011 by Mike Szczys 30 Comments

Did you know that most AVR chips have a type of hardware exclusive OR (XOR) option when it comes to the logic levels of the output pins? If you look in the datasheet (the image above is a screenshot from an ATtiny13 datasheet) you’ll find a section on Toggling the Pin. It turns out that if you set a PORT as an output, writing logic one to the corresponding PIN register will toggle the logic levels of that out. This is really easy to overlook if you’re writing in C, but I’ve been working on learning a bit of assembler language and found this to be very useful. Keep reading after the break and I’ll tell you how I happened upon this info and what it’s good for.

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Disco Isn’t Dead: Diy Dance Floor Spotted At Student Parties

June 18, 2011 by Mike Szczys 16 Comments

Your party is lame if it doesn’t include interactive blinking lights on the dance floor. [Mario] and [Lukas] didn’t want to have lame parties, so they enlisted some fellow students to build an interactive dance floor (translated). The finished party-piece is 4 meters by 2.5 meters (that’s about 13’x8′ for us yanks) and includes 160 lighted squares. But it’s the electronics that really make this a heavy project.

Milled into the underside of the pressboard base are a series of pockets and channels to hold various components. If you look hard enough, you’re going to find eight AVR microcontrollers which control the LEDs, 8 CPLDs to manage the weight sensors which make the floor interactive, and an FPGA and embedded computer to tie everything together. It’s movable, a hit at parties, and so far it seems to hold up to the occasional spilled beverage.

You can’t share a project like this without some video. See it after the break.

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Programming An ATtiny Using An Arduino

May 29, 2011 by Mike Nathan 24 Comments

attiny

[Scott] is a big fan of the Arduino platform, and he’s not afraid to admit it. It does all the things he needs, but now and again he would like to use something a bit smaller, without all the bells and whistles the Arduino has to offer. He contemplated using an ATtiny for smaller projects, but after looking into what he would need to program the chip under Linux, he could never find the motivation to give it a go.

That all changed when he discovered the Arduino-Tiny project, which aims to bring a limited Arduino IDE to the ATtiny line of microcontrollers. He found the project to be quite useful, so he put together a brief tutorial that walks through everything you need to get started.

The tutorial is fairly straightforward, and even demonstrates how the Arduino can be used as an ISP for the ATtiny, removing the need to purchase a standalone programmer. Be sure to check it out if you are searching for an easy way to get started with ATtiny chips under Linux.