Knut Karlsen at blog.bareknut.no writes:
At home i always have some batteries lying around, either rechargeable or normal ones. Usually they are empty, but i’d like them to be always fully charged. I could use a normal charger and there is a lot of solar devices that charge rechargeable batteries. I wanted it simpler; why hasn’t anyone made a battery with integrated solar cells? The idea of the “SunCat” batteries where born.
Solar cell batteries - [Link]
We set out to build a 100% DIY, scratch-built digital picture frame. Our frame has a 12bit color LCD, gigabytes of storage on common, FAT-formatted microSD cards, and you can build it at home. We’ve got the details below.
Digital picture frame – 100% DIY - [Link]
Display on QVGA 240×320 pixel using AVR small 8 bit microcontroller
Build photo frame with AVR and BL-TFT240320PLUS - [Link]
Arduino pH meter - [Link]
This is the second version of a homemade CNC machine build using mostly off the shelve parts. The first one aka “The beast” had a lot of precision issues due to play in most parts which in turn was caused by mostly bad cutting. Also one of the biggest problems was that when I have build it I did not think to allow later adjustments to be done. So this time almost every part of it allows for some adjustments. It is also easier to build due to the different design. [via]
$100 Arduino based CNC - [Link]
This is a very simple IR light dimmer that you will wish to have sooner or later, especially those who are lazy enough to get up and turn off the lights. There are two versions of PCB for two sizes of capacitors, so PCBs are: 32.5 x 26.5mm and 28.5 x 27mm.
IR light dimmer - [Link]
I have been wanting to build a streaming radio for some time. I frequently work in my garage, where I occasionally use my Macbook to play music through a small amplifier and bookshelf speakers. The problem is that my laptop is not always set up in the garage, and greasy fingers are not a good thing to have around a white laptop, period. I could simply buy an internet radio, but I couldn’t stomach the $150-$300 price tag on most players for such a luxury.
So I decided to build one instead.
Building a Wifi Radio - [Link]
In everything from computer processor chips to car engines to electric powerplants, the need to get rid of excess heat creates a major source of inefficiency. But new research points the way to a technology that might make it possible to harvest much of that wasted heat and turn it into usable electricity.
Turning heat to electricity - [Link]
So there are a ton of instructables covering the use of high brightness leds. Many of them use the commercially available Buckpuck from Luxdrive. Many of them also use linear regulation circuits that top out at 350 mA because they are highly inefficient. This instructable serves to let people know that there are other options out there to drive high power leds.
1.5A Constant Current Linear Regulator for LEDs - [Link]
This SMPS boosts low voltage (5-20 volts) to the high voltage needed to drive nixie tubes (170-200 volts). Be warned: even though this small circuit can be operated on batteries/low voltage wall-worts, the output is more than enough to kill you!
EagleCAD CCT & PCB files
MikroBasic Firmware Source
High Voltage Switch Mode Power Supply (SMPS)/Boost Converter for Nixie Tubes - [Link]