[Vincent] on the EEVblog forums had an idea for an inexpensive resistor substitution decade box.
The build uses cheap decimal thumbwheel switches he bought on eBay. Each switch is wired up with resistors for each digit, and each switch is wired up in series. The result is a small, easy to read resistor box with a range of 1 Ω to 10 MΩ.
[Patrick] wanted a remote control to control some of the robots he’s built. He also wanted to get some data back from his robots, so an inexpensive off-the-shelf solution wouldn’t be up to the task. Like all good geeks, [Patrick] decided to build what he needed.
For analog control, [Patrick] decided to use a Wiimote nunchuck. This turned out to be a very good choice – the nunchuck has a 2-axis joystick and 3-axis accelerometer in one small, easy to interface package . The wireless radio is taken care of with an XBee module. For the microcontroller, custom “lcd backpack” was created that provides an I2C port for the nunchuck, inputs for the buttons and the single pot, and 2 serial ports for the FTDI and XBee.
Instructables user [mzsolt] enjoyed making his own PCBs, but he wanted to speed up the etching process just a bit. While some people put together elaborate bubble tanks and agitators, he wanted to keep his simple and more importantly, cheap.
He looked around the house and discovered an ancient CD-ROM drive that was collecting dust, which he figured would make a great agitator for smaller projects. He picked up a decade counter and a handful of other cheap components, then got busy pulling the drive apart. He connected the motor and the drive’s limit switches to the decade counter, which controls the entire setup.
When powered on, the drive ejects, taking his container full of etchant with it. When the drive hits the outer limit switch, the decade counter reverses the motor until it hits the inner switch, reversing the motor once again.
As you can see in the video below, it works reasonably well. He suggests using a variable power supply to regulate the motor’s speed, but a variable pot would probably work just as well. Obviously the agitator is best suited for smaller projects, but since it was so cheap to put together, you won’t hear us complaining.
Continue reading “Cheap And Easy PCB Agitator From An Old CD-ROM”
When you cut something out, you lose a bit of material in the process. Think of a table saw and the sawdust it produces, that’s the waste material lost in an area the width of the blade. It’s really easy to measure that, just measure the blade. But [James] started wondering about a good way to measure material loss from a laser cutter.
Why does it matter? If you’ve designed pieces that should fit together with each other, loss of material can lead to joints that aren’t tight. [James] figured out that the loss could be measured by making several cuts within a rectangular frame. You can see his test pieces above, with ten strips cut out of each frame. After the laser is done doing it’s work just slide all the pieces together and measure the opening created at one end. It helps to have an enhanced caliper to make the measurement easy to read. Now divide that distance by the number of laser passes and account for that dimension next time you design parts for the cutter.
Students in the BASTLI lab at the Swiss Federal Institute of Technology Zurich had been stuck using underpowered and unreliable saws for quite some time. The saws often got stuck while cutting through PCBs and were generally a drag to use. When group member [Mario Mauerer] came across a big and powerful brushless motor in his basement, he decided it was time to upgrade the lab’s cutting tools.
Along with fellow student [Lukas Schrittwieser] he built a test rig to see how powerful the motor really was, and satisfied with the results, the pair set off to build their own table saw. The enclosure was wrapped up pretty quickly, leaving the pair to source a power supply. Rather than purchase one, they built a 700w monster switching PSU to power their saw.
As you can see in the video below the saw chews through most things with the greatest of ease, but the students added a “boost button” to the saw just in case they need to run it at full tilt.
While we can’t exactly overlook the lack of finger and eye protection in their demonstration, it does look like a great little tool to have around.
Continue reading “DIY Table Saw Cuts Through Anything, Leaves No Room For Mistakes”
The team at nonolith labs announced their CEE, a device for billed as, “an analog buspirate” that is meant to control, experiment, and explore the world of analog electronics. Nonolith labs started a kickstarter campaign for the CEE.
The CEE is capable of sub-millivolt and milliamp sampling at 44.1k samples/second, and sourcing 2 channels of 5V @ 2A with a little bit of soldering. This allows for precise control of motors and sensors with the web-based UI. We’re thinking this would be a great way to teach high schoolers the art of electronics, and would be great combined with a few lectures from Paul Horowitz.
The CEE ties into nonolith labs Pixelpulse, a pretty handy tool for visualizing analog and digital signals. You can check out a demo of Pixelpulse simulating a charging capacitor here.
We’re hoping this focus on education on analog electronics catches on – you can learn a lot more by building a 555-based mini Segway than you can slapping a microcontroller in every project. This would go under the same theory as, “any idiot can count to one.”
Check out the video of the CEE on the kickstarter campaign page.
If you’ve been spending hours with the digital calipers while designing enclosures for your circuit boards there may be a better way. [Phil] tipped us off about a new software package that will let you import PCB layout files into Google Sketchup. This way you can start working on the enclosure in CAD before you’ve populated your first board. Of course this adds to the pain of realizing there’s an error in your layout, but what are you going to do?
The free software was developed by RS Components, a European component distributor. It takes IDF files, which can be exported from most PCB design software, and converts them to a format compatible with Sketchup, Google’s 3D design software. For those who enjoy a very dry demonstration video you won’t want to skip seeing what we’ve embedded after the jump.
We’re kind of surprised that this hasn’t already been done. If it has, leave a link in the comments.
Continue reading “Importing PCB Layout Into Google Sketchup”
