AVR Light Controller

January 30, 2009 by Caleb Kraft 12 Comments

halogen

[Matthias] sent us this project where he builds an AVR light controller. He had a halogen bike light laying around, but was unsatisfied with its lead-acid battery. He wanted to use a lithium-polymer battery but found that they can’t be used directly with halogen lamps due to their voltage. His produced 8.5 volts at full charge and can’t be discharged to below 5 volts. He new a power controller would be necessary to try to flatten that out for his lamp, which needed to stay between 6-12 volts.

He used an ATtiny45 doing PWM to change the voltage. Some other cool features he added were the high and low settings and an LED status light for warnings. You can find pictures, schematics and source code on his page as well as tons of great information. Great job [Matthias].

LED Push Buttons

January 29, 2009 by Caleb Kraft 39 Comments

[pros] has come up with a very elegant way of making lighted buttons (translated). Using a bunch of small push buttons harvested from old CD players, he rigged this unique way of mounting LEDs. Each LED has two buttons under it. They are wired in parallel, so if either of them is pushed, the button works. The LED isn’t actually soldered where it passes through the board. The anode and cathode are bent around and soldered to allow the LED a little bit of travel. There’s a good picture of how he did this on the site. The rest of the details might be hard to decipher though, it looks to be in dutch.

[thanks Tom]

Wireless Bootloading

January 28, 2009 by Caleb Kraft 3 Comments

[vimeo= 2976417]

Tired of having to physically connect to your microprocessor to upload new code? Just do it over a wireless connection. [Nathan] takes us through the process of setting up a wireless bootloader for the ATmega168. He is using the XBee base and remote modules for the wireless communication. While people have been doing wireless bootloading with the Arduino already, [Nathan] found that it was common for them to have timeout issues. His remedy was to make his own custom one that is much faster. He’s asking for help though. At this point it is tested and working, but he needs someone with more programming knowledge to help him make it “drop-in” compatible with the Arduino IDE.

Don’t forget to submit projects to our tip line.

5 Cent Tilt Sensor

January 28, 2009 by Caleb Kraft 27 Comments

5cent

This is a 5 cent tilt sensor. We know it cost more than 5 cents, but it is in fact a tilt sensor that utilizes a 5 cent coin. We’ve all done quick hacks to make quick sensors for various projects. We’ve seen tons of them, from stealing springs out of pens and shoving a resistor through them for flexible contact switches, to tin foil touch sensors. This one is new to us though. The design is fairly simple, you insert 4 bits of wire to serve as contacts and the coin will make contact with only two at a time. It isn’t analog, it isn’t extremely precise, but it is super quick and easy. Thanks for sharing [ix].

Thermosonic Wedge Bonding

January 27, 2009 by Caleb Kraft 12 Comments

hot

In the past, if we’ve been doing smd soldering, we’ve used pretty basic hot plates. This project takes that idea a bit further. Since [kc6qhp] will be using parts that aren’t conducive to soldering, he has to use wire bonding. After locating a fairly cheap wire bonding machine and microscope, he built the heated stage to fit perfectly with his other tools. You’ll notice that he has machined a lip around the heat plate for small custom C-clamps as well as made it adjustable height. Very nice work [kc6qhp].

Ferric Chloride Etching Chemistry

January 26, 2009 by Eliot 14 Comments

[ladyada] has republished an interesting snippet from the synthDIY mailing list. [David Dixon] discusses the actual chemistry behind ferric chloride based home circuit board etching. He concludes that ferric chloride is essentially a ‘one-shot’ oxidant. It can’t be regenerated and can be difficult to dispose of properly. The use of acidified copper chloride is a much better path and becomes more effective with each use, as long as you keep it aerated and top up the acidity from time to time. This etchant solution is actually the result of initially using hydrogen peroxide as an oxidant along with muriatic acid. You can see us using this solution in our etching how-to and while creating the board for our RGB lock. For more information on using hydrogen peroxide, check out [Adam Seychell]’s guide and this Instructable.

Aside: [ladyada] has added the receiver code to the Wattcher project page.

Wattcher, Twittering Kill A Watt Plans Posted

January 24, 2009 by Eliot 20 Comments

You probably saw [Phillip Torrone] and [Limor Fried]’s twittering Kill A Watt earlier this week. It was an entry in the Core77/Greener Gadgets Design Competition. We saw a little bit about how it was assembled, but now they’ve posted a full guide to assembling the hardware. Each Kill A Watt gets an XBee radio that transmits back to a receiver that logs the power usage. The difficult part when putting this design together was the XBee required 50mA when transmitting. This is well above the Kill A Watt’s internal power supply. They remedied this by adding a 10,000uF supercap to act as a rechargeable battery. The daily twittering is just a side-effect of the project. The Kill A Watts transmit every 2 seconds, so you’ll get a very accurate report of your power usage. This is a great project for renters who can’t permanently modify their power infrastructure. Each Kill A Watt can support quite a few appliances since they’re rated for 15A, ~1800W.