Vowel recognition using an ATmega644

[Youchun Zhang] and [Annie (Wei) Dai] found a way to differentiate vowel sounds using an ATmega644 as their final project for a microcontroller design class. Voice recognition is not out of the ordinary, but most of the time it uses a computer, smart phone, or specially designed hardware. This implementation uses an ATmega644, a microphone connected via an op-amp, and a few buttons. In the demonstration after the break you’ll see that they’re outputting status data to Putty via an RS232 connection, but that’s just so you can see what’s going on inside the chip. It’s what’s doing all of the hard work.

In order to tell the difference between vowels, the waveforms of each sound were analyzed using MATLAB during the research phase. That analysis allowed the team to assemble data for each sound that contained the peaks least often found in the other sounds. Now the microcontroller analyzes incoming sound, comparing it to that data set. The analysis is snappy, happening in real-time thanks to the team’s use of the Fast Walsh Transform. It turns the sound into a set of square waves and presents them as a 64 bit sample. The result can be used as a password protection scheme, but as far as we can tell this doesn’t key to just one person, anyone who knows the vowels of the password can use it.

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Bootloader burning basics

[Charles Gantt] and a few others were having trouble burning the Sanguino bootloader to an ATmega644 chip. With some help from the [Nils Vogil] via the RepRap IRC [Charles] got it worked out and wrote a guide for burning the bootloader using an Arduino as an ISP programmer.

We’re not familiar with the specifics of the Sanguino bootloader, but [Charles] mentioned that he was unable to flash it onto the AVR chip without a resonator. The resonator serves as an external clock source for the chip. We’d bet the programming process changes the fuse settings on the chip to use an external source. Without that source, you won’t be able to communicate with the chip afterwards.

The solution just adds the resonator to the programming circuit. This should be useful when burning any bootloader using an Arduino. But it does make us wonder if there isn’t an alternative method that would let you draw the clock signal from the Arduino itself?

Automating Rock Band vocals

rockband_audio_simulator

When it comes to Rock Band, our friends suck at singing. No, really.

We’re cool with them beating on the drum set completely off-time, but the sound of them trying to sing “Tom Sawyer” makes us want to cut out our eardrums.

We’re willing to bet that Cornell students [Gautam Kamath and Dominick Grochowina] have friends like ours. Their Electrical and Computer Engineering final project aims to remove the tone deaf from in front of the microphone, allowing a computer to sing vocals instead.

Since Rock Band simply listens for the proper frequency to be sung, the pair figured it would be easy enough to monitor the game’s output and feed computer-generated signals back into the microphone. Once the game’s vocal bar is isolated via a series of filters, an ATMega644 is used to interpret the notes and generate the corresponding tone via a speaker.

While automating Rock Band gameplay is nothing new, we don’t recall seeing anyone try to cut the singer from the band. We think it’s a pretty cool concept – rock on!

Edit: Updated with video

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Touch-based synthesizer is a wiring nightmare

[Jane] wrote in to let us know about the touch-based synthesizer she and her classmates just built. They call it the ToneMatrix Touch, as it was inspired by a flash application called ToneMatrix. We’re familiar with that application as it’s been the inspiration for other physical builds as well.

A resistive touch screen in the surface glass of the device provides the ability to interact by tapping the cells you wish to turn on or off. Below the glass is a grid of LEDs which represent sound bits in the looping synthesizer track. Fifteen shift registers drive the LED matrix, with the entire system controlled by an ATmega644 microcontroller. Although the control scheme is very straight forward, the jumper wires used to connect the matrix to the shift registers make for a ratsnest of wireporn that has been hidden away inside the case. Check out the demonstration video after the break to see what this looks like and sounds like when in use.

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DIY hot air reflow station

Add to you bench tools by building this hot air reflow station. [Tobi] had a difficult time and was getting frustrated with the reflow oven he was building. He ditched that and set out on this project after drawing inspiration from a hot-air pencil project.

Pictured above is the business end of the device. On the right you can see the tubing that delivers air from an aquarium pump. At the center of the probe is a glass tube containing the heating element. A thermocouple is monitored by an ATmega644 to maintain the desired air temperature which can be dialed in on the base unit. This thing can put out air that’s around 500 degrees Celsius which has cause some problems with melted tubing and singed spacers. The final design includes a cover that fits over everything and hopefully provides adequate thermal isolation for the user’s hand.

[Tobi's] base unit include faceplates for the front and back milled out of copper clad board. This really makes the tool look a bit more trustworthy. He assures us that there is a demonstration video on the way.

Monitoring the Engine Control Unit

Is there a place in the dashboard of your high performance automobile for this Engine Control Unit feedback panel? There’s several methods of showing information at work here. The row of LEDs at the top of the bezel provide RPM feedback. The two red LEDs with chrome bezels are alarm indicators. But that big OLED display is the centerpiece of the unit. Not only can you scroll through a myriad of display options, but the screen packs more than enough contrast to be readable during the day. It looks like [Mathieu] is selling these units and has decided not to release source code because of this, but there’s a schematic available and a video after the break shows the menu system from which you can draw inspiration.

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Shiny motorcycle computer

We’re rather surprised at how popular it has become to build your own motorcycle computer. [Mario Mauerer] tipped us off about his shiny motorcycle computer (translated) for his Yamaha XTZ 750. It uses an ATmega644 microcontroller to pull a variety of data together and display it on this white LED backlit display. He connected a flow meter to the fuel line to monitor gas consumption. Oil temperature is captured by inserting a brass tube (containing the sensor) through a hole in the oil cap and soldering it in place. Water temperature is gathered by measuring the external temperature of one of the cooling lines. [Mario] uses a rotary encode with a click function as the control interface device, and a battery backed real time clock keeps time.

A quick look at the PCBs tells the tale of good circuit design. But we do wonder about catching the reflection of the sun in that shiny bezel.