MSP430 alarm clock project

msp430-bedside-alarm-clock

[Markus] turn his breadboard LED matrix tinkering into an alarm clock which wakes him each morning.

Don’t be fooled by how clean his assembly work is. That’s not a fabbed PCB, it’s a hunk of green protoboard which a lot of point-to-point soldering on the back side. It’s driven by the MSP430 G2452 which is oriented vertically in this image. The two horizonal ICs are 595 shift registers which drive the LED modules.

We already mentioned the cleanliness of his assembly, but there’s one other really cool design element. On the back of the unit is what looks like a battery holder for two AA cells. He’s using just one Lithium Iron Phosphate battery (3.2V) which is in the upper of the two cavities. This let him cut the lower part of the holder at an angle to act as a stand for the clock.

Don’t miss the video which walks us through the user interface. It has what you’d expect from an alarm clock. But there is a really bright white LED which mimics a sunrise clock and it does more than just buzz one note when the thing goes off.

[Read more...]

Plastic bottles funnel rain into rain barrels

plastic-bottle-downspout

This is [Wombling's] no-cost solution to getting rain from his gutters into a rain barrel. It is literally just a bunch of plastic water bottles chained together. At one end he uses the original cap with some holes punched in it as a sieve.

We like the concept, but find the execution a bit dubious. In heavy rain the holes in the cap will not be able to keep up and we figure your gutters are going to overflow. That may be okay depending on the grade of your landscaping, but those who value keeping their basement dry should avoid this route.

Just a bit of improvement could change all that though. We suggest making the rain barrel the sieve. Add a bowl shape to the lid with a large piece of screen in the bottom to filter out debris. Then form some type of spout on the front side of the lid to channel overflow away from the house.

The amount of waste generated by bottled water has always troubled us, which is part of the reason we featured this. We also liked seeing those plastic bottle skylights, and could swear we featured a floating plastic bottle island built in the ocean but couldn’t find the link. If you know what we’re talking about leave the goods in the comments section.

Copper kettle just for the hipster coffee scene

04-copper-kettle

Handmade coffee is a feature we need to write. But for now we present this copper kettle which is designed to pour out the boiling water very slowly in order to achieve the perfect cup of slow-drip java.

[CHS] made the kettle for his friend [Nate]. The entire process starts off with an arc of flat copper sheet which makes a slightly conical cylinder when curved until the two ends meet. Getting a water tight seal on this seam is imperative and it took four or five tries to reach perfection.

To get the kettle in shape [CHS] improvised a mandrel out of a thin slice of railroad track. After polishing it smooth it goes on the inside of the copper and gives him something to hammer against. We think this step is magic… It’s kind of like the old sculpting adage that you remove everything that isn’t what you’re trying to end up with. The beauty of the piece really pops out as the final curves are hammered into the work.

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Filtering out mains hum from ADC samples

Hum_filter

A little light reading means something different to us than it does to [Hamster]. He’s been making his way through a book called The Scientist and Engineer’s Guide to Digital Signal Processing written by [Steven W. Smith, Ph.D]. Being the hacker type, a million different uses for the newfound knowledge popped to mind. But as a sanity check he decided to focus on a useful proof of concept first. He’s come up with a way to filter out the mains hum from Analog to Digital Converter samples.

Mains hum is all around us; produced by the alternating current in the power grid that runs our modern lives. It’s a type of interference that can be quite problematic, which is on reason why we see EMF sensor projects from time to time. Now you can filter that ambient interference from your projects which take readings from an ADC. This would be quite useful for applications which measuring teeny signals, like ECG hacks.

[Hamster] did a pretty good job of presenting his demonstration for the uninitiated. He even provides examples for Arduino or FPGA projects.

Fluorescent light, powered by battery

light

If you’re going camping this summer, or just want a cheap emergency lantern powered by a pair of AA batteries, you probably can’t do much better than [rimstar]‘s Joule thief compact florescent lantern.

The circuit for [rimstar]‘s battery powered CFL bulb is a Joule thief. While these circuits are usually used as a demonstration to get every last bit of energy out of a battery with a LED, [rimstar] upgraded everything with a better transformer and a power transistor to light up a CFL bulb.

What’s really interesting about this build is it provides a use for blown compact fluorescent bulbs. The normal failure mode of these light bulbs is usually the electronics going bad, not the tube. By replacing the electronics with a homemade circuit, it’s an easy way to reuse these broken bulbs.

Video below.

[Read more...]

A robotic tattoo artist

tattoo

Here’s something we thought we’d never see: a robot that turns a computer drawing into a tattoo on the user’s arm.

The basic design of the robot is a frame that moves linearly along two axes, and rotates around a third. The tattoo design is imported into a 3D modeling program, and with the help of a few motors and microcontrollers a tattoo can be robotically inked on an arm.

Since the arm isn’t a regular surface, [Luke] needed a way to calibrate his forearm-drawing robot to the weird curves and bends of his ar.  The solution to this problem is a simple calibration process where the mechanism scans along the length of [Luke]‘s arm, while the ‘depth’ servo is manually adjusted. This data is imported into Rhino 3D and the robot takes the curve of the arm into account when inking the new tat.

Right now [Luke] is only inking his skin with a marker, but as far as automated tattoo machines go, it’s the best – and only – one we’ve ever seen.

Fun with LED matrix and mouse

fun-with-LED-matrix-and-mouse

[Brad] just acquired a 32×32 RGB LED matrix and he jumped right into the deep end with his first project. To try out his skills on the device he used an Arduino to drive a slew of pixels with bouncing-ball physics.

The demo starts off with a hail storm of multi-colored falling pixels. In the center of the storm is the cursor, which he controls with a PS2 mouse. That happens to be a ball mouse which makes sense as we don’t remember having seen any optical mice as of late that weren’t USB. The PS2 protocol is easy to read using a microcontroller; more about that in [Brad's] project write up.

By holding down the left mouse button he can draw persistent pixels on the screen. The falling balls then interact by bouncing off of the obstacles. The image above shows a frame on three sides of the screen which has trapped the pixels near the bottom. He can also erase pixels, which has the effect of draining the trapped balls like a hole in a bucket of water. Neat!

Bouncing ball physics are fun to experiment with. Here’s one being driven by an analog computer.

[Read more...]

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