Year: 2011

Sound Treating A Studio

December 6, 2011 by 14 Comments

Looks like [Dino] is getting the band back together. After a junkyard tube amp and a DIY tremolo stompbox, he’s back again, this time doing a bit of sound treatment in his studio.

Most rooms naturally have a bit of flutter echo. You’ll notice this when you move into an apartment or new house – rooms sound a lot more cavernous without rugs, drapes and furniture. Unfortunately, having a bunch of couches doesn’t bode well for the workflow in a studio despite what MTV Cribs may have told us. The usual solution is to put up some sound-absorbing material on the walls, and a metric ton of cardboard egg cartons don’t work.

[Dino] found a bunch of acoustic panels his neighbor threw out during a renovation (yes, we know, he’s very lucky). After doing some pre-installation tests, the panels were hung. Afterwards, the amount of echo was drastically reduced.

The good news is we finally get a look inside [Dino]’s studio. We saw the junkyard tube amp we covered earlier, but not the neat tremolo pedal he made.

Check out [Dino]’s video of sound treating a room after the break.

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AVR External Memory Interface (XMEM) Reads Input Matrix

December 6, 2011 by 3 Comments

Reading from a large number of inputs, like this piano keyboard, can be tedious. Even when multiplexing there’s a lot to keep track of. But if you choose the right microcontroller, you may have hardware assistance. Here’s an ATmega640 is using it’s external memory interface to read the key matrix.

You may remember the Open Music Labs article about reading from a shift register using just one pin of a microcontroller. This time around a shift register is still used, but instead of pulling in a long line of parallel inputs, the switches are multiplexed to reduce the number of I/O pins used to read them.

A 74HC573 is used to facilitate the multiplexing. We won’t go into how that part is accomplished; there’s a separate post that explains the process. What’s unique here is that the XMEM peripheral of the AVR microcontroller is used to grab the data. This is intended for external memory chips, but if you get the timing just right, it greatly simplifies reading in a matrix of up to 128 inputs.

Playing Classic 60s Tunes With An All Electronic Band

December 6, 2011 by 16 Comments

house-of-the-rising-sun

If you are considering repurposing some old computer equipment to create music, be aware that the bar has been raised just a tad. YouTube user [BD594] spent some time sifting through his bin of used electronics and put together a 5-piece band that plays a pretty awesome rendition of The Animals’ “House of the Rising Sun”.

Last week, we saw a pretty impressive hack with a floppy drive that could bang out music using a calculator, but this takes things to a whole new level. [BD594] used an old HP ScanJet to simulate the song’s vocals, while an Atari 800XL combined with an oscilloscope is used as an organ. A Ti-99/4a is used in conjunction with another scope to play guitar notes, while a PIC-controlled hard drive does double duty, playing both the bass drum and cymbals.

We dare you to watch the video below and NOT be thoroughly impressed with his work.

[BD594] says that once he has a bit of free time, he’ll be putting out another video – something we’ll be anxiously waiting to see.

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This Toy Intercom System Is Way Better Than A Pair Of Tin Cans And Some String

December 6, 2011 by 36 Comments

toy-intercom-system

On his blog, [Kenneth Finnegan] recently showed off a replica of a fun toy he used to play with as a kid, a telephone intercom system. The setup is pretty simple, requiring little more than a pair of analog phones, a battery, and a resistor.

The phones are connected to one another using a standard telephone cable, but [Kenneth] uses a 9v battery to introduce a small bias current into the loop, allowing the speakers at either end to hear one another. He also added a small LED into the circuit so that there is a visual indication as to when both handsets are off hook.

The setup is very simple at the moment, though [Kenneth] does have some ideas in mind to enhance his intercom system. He hopes to tweak the remote phone to ring when the local phone is picked up, among other things.

Telephone technology is nothing new, but for just a few dollars (or less) your kids can be entertained for hours as [Kenneth] was way back when.

Continue reading to see a short video overview of the phone system, and be sure to share your ideas for enhancing it in the comments section.

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Two Telescope Improvements

December 6, 2011 by 5 Comments

Despite being a college class everyone regarded as an easy ‘A,’ astronomy is very hard work. Not only do many hours go into capturing a single image, the equipment itself must be constantly monitored well into the freezing cold of night. [Jerry] sent in a few neat projects that have made his nights much more comfortable.

First up is a mod for a focus controller. The focus of a telescope changes constantly with temperature, atmospheric conditions, and especially what filter is being used. The stock USB-nSTEP focuser [Jerry] used required hard-to-find unipolar steppers, so he modded his USB-nSTEM to accept bipolars with a Pololu A4988 driver.

Next up is [Jerry]’s very impressive DIY Off-axis guider that he machined himself. An off-axis guider allows an astronomer to guide the ‘scope without having to deal with a dinky, surprisingly flexible guide scope. We’re really impressed with [Jerry]’s machine skills, but that’s what you get when you’ve got an awesome mill like his.

Update: Tiny Line-follower And More

December 5, 2011 by 27 Comments

This tiny line-following robot is quite impressive. It’s [Ondrej Stanek’s] second take on the design, which he calls PocketBot 2. Just like the earlier version, this robot is small enough to fit in a matchbox, but it’s received several upgrades in this iteration.

The coin cells that ran the previous version have been replaced by a rechargeable Lithium Ion cell. The ATmega8 which controlled the first robot has been swapped out for an ATmega128 running at 32 MHz. You won’t find an IR receiver on this one either, it’s been traded for a Bluetooth module which adds a quantum leap in functionality. For instance, the graph in the upper left of this photograph shows the reflective sensor data readings used to follow the line.

There’s all kinds of great engineering in this design, which is shown off in the video after the break. One of our favorite parts is that the axles are attracted to the center of the robot by one rare-earth magnet. This keeps the rubber tires pressed against the motor spindles rather than use a gearing system.

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Slowing A Bopit So The Littles Ones Can Play Too

December 5, 2011 by 11 Comments

[Johnny Halfmoon] wanted to help out his three-year-old who was fascinated by the Bopit electronic game. In its stock condition it’s a bit too fast for the young one, so he cracked it opened and added the option to slow things down.

Above you can see the Bopit Extreme with the top half of the case removed. Although not hard to get open (there’s just 12 screws to remove) the spring-loaded appendages will fly apart when you do. He warns to pay attention at how they go back together.

There’s one axial resistor which affects the running speed of the game. [Johnny] desoldered this, replacing it with a circuit that toggles between that original resistor and a potentiometer. Now, one switch position allows for normal play, the other allows for adjustable speed based on the potentiometer position. Check out the results in the clip after the break.

Looking for some other fun electronic toy hacks? Why not try out this cursing Simon Says?

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