Fake Window Brings Natural Light Into Basement

February 29, 2016 by 27 Comments

Do you have a depressing basement? Maybe you still live with the parents? You need a fake window to cheer things up! As it turns out, it’s pretty easy to make a convincingly real-looking day-light window — plus you could totally mess with your circadian rhythm!

[thatdbeagoodbandname] has an office in his basement with no windows, which is why he set out to brighten up the room with this project. Apparently you can buy fake LED windows, but they’re expensive and don’t look that good. His goal was to build a cartoony “classic” window that would feel bright and uplifting — and to keep it well under $200.

In the end he ended up buying everything he needed from Home Depot for his project; some 2 x 4’s for the frame, a sheet of acrylic, and a set of LED plant grow-lights. Continue reading “Fake Window Brings Natural Light Into Basement” →

Design Analysis: Core XY Vs H-Bot

February 29, 2016 by 26 Comments

Hackaday writer [Joshua Vasquez] wrote about the mechanical difference between the Core-XY and H-Bot movements commonly used in 3D printers on his personal website. There are so many things a beginning mechanical designer can overlook when setting out to make a movement. Sometimes,in the case of these movements, they aren’t readily apparent, and like finding a troublesome pattern in code; have to be shown before the mind picks them up in future designs.

[Joshua] starts by describing how each movement works. At first glance, the H-Bot movement seems simpler and more effective than the Core-XY.  The Core-XY uses more belting, and some of the pulleys are out of plane with each other. However, this is done to eliminate a moment put on the frame in the H-Bot design. This moment can throw off the accuracy of the movement in unpredictable ways.

The Core-XY movement is one of our favorites. It keeps the motors stationary. It’s compact, precise, repeatable, and linear. It’s good to understand the mechanical reasons for this. Just like learning the SQL database calls a library has been obfuscating for you lets you write better code.

Build Your Own Sensor Skin

February 29, 2016 by 25 Comments

Scientific research, especially in the area of robotics, often leverages cutting-edge technology. Labs filled with the latest measurement and fabrication gear are unleashed on the really tough problems, like how to simulate the exquisite sensing abilities of human skin. One lab doing work in this area has taken a different approach, though, by building multi-functional sensors arrays from paper.

A group from the King Abdullah University of Science and Technology in Saudi Arabia, led by [Muhammad M. Hussain], has published a fascinating paper that’s a tour de force of getting a lot done with nothing. Common household items, like Post-It notes, kitchen sponges, tissue paper, and tin foil, are used to form the basis of what they call “paper skin”. Fabrication techniques – scissors and tape – are ridiculously simple and accessible to anyone who made it through kindergarten.

They do turn to a Circuit Scribe pen for some of their sensors, but even this nod to high technology is well within their stated goal of making it possible for anyone to fabricate sensors at home. The paper goes into great detail about how the sensors are made, how they interact, and how they are interfaced. It’s worth a read to see what you can accomplish with scraps.

For another low-tech paper-based sensor, check out this capacitive touch sensor keyboard.

Thanks for the tip, [Mattias]

Spice Power

February 29, 2016 by 8 Comments

Spice is a circuit simulator that you should have in your toolbox. While a simulator can’t tell you everything, it will often give you valuable insight into the way your circuit behaves, before you’ve even built it. In the first installment of this three-part series, I looked at LTSpice and did a quick video walkthrough of a DC circuit. This time, I want to examine two other parts of Spice: parameter sweeps and AC circuits. So let’s get to it.

schem2In the first installment, I left you with a cliffhanger. Namely the question of maximum power transfer using this simple circuit. If you run the .op simulation you’ll get this result:

--- Operating Point ---
V(n001): 5 voltage
I(R1): 0.1 device_current
I(V1): -0.1 device_current

The power in R1 (voltage times current) is .5 W or 500 mW if you prefer. You probably know that the maximum power in a load occurs when the load resistor is the same as the source resistance. The Rser parameter sets the voltage source’s internal resistance. You could also have created a new resistor in series with V1 and set it explicitly.

Continue reading “Spice Power” →

2,100 Mechanical Mechanisms

February 29, 2016 by 29 Comments

[Nguyen Duc Thang]’s epic 2100 Animated Mechanical Mechanisms is one of the best YouTube channels we’ve ever seen. A retired mechanical engineer, [Nguyen Duc Thang] has taken on an immense challenge: building up 3D models of nearly every imaginable mechanism in Autodesk Inventor, and animating them for your amusement and enlightenment. And, no, we haven’t watched them all for you, but we’re confident that you’ll be able to waste at least a couple of hours without our help.

If you’re actually looking for something specific, with this many mechanisms demonstrated, YouTube is not the perfect lookup table. Thankfully, [Nguyen Duc Thang] has also produced a few hundred pages of documentation (PDFs, zipped) to go along with the series, with each mechanism classified, described, and linked to the video.

This is an amazing resource as it stands, and it’s probably a good thing that we don’t have access to the 3D files; between the filament cost and the time spent shepherding our 3D printer through 2,100 mechanisms, we’d be ruined. Good thing we don’t know about the Digital Mechanism and Gear Library or KMODDL.

Thanks [alnwlsn] for the tip!
Continue reading “2,100 Mechanical Mechanisms” →

PCB Laminator Is Its Own Project

February 29, 2016 by 21 Comments

One of the easiest ways to make PC boards at home is to use the toner transfer method. The idea is simple: print the artwork using a laser printer and then use a clothes iron to transfer the toner from the paper to a clean copper clad board. The toner is essentially plastic, so it will melt and stick to the board, and it will also resist etchant.

There are several things you can do to make things easier. The first is the choice of paper. However, the other highly variable part of the process is the clothes iron. You have to arrange for the right amount of heat and pressure. If you don’t do a lot of boards, you’ll probably have to make several passes at getting this right, scrubbing the reject boards with acetone and scouring pads to clean them again.

[Igor] had enough of the clothes iron and knew that other people have used lamination machines to get the toner off the paper and on the blank board. He started with a commercial laminator but hacked it for PID control of the temperature and made other improvements.

Continue reading “PCB Laminator Is Its Own Project” →

SensorTape Unrolls New Sensor Deployment Possibilities

February 29, 2016 by 20 Comments

An embedded MEMS sensor might be lots of fun to play with on your first foray into the embedded world–why not deploy a whole network of them? Alas, the problem with communicating with a series of identical sensors becomes increasingly complicated as we start needing to handle the details of signal integrity and the communication protocols to handle all that data. Fortunately, [Artem], [Hsin-Liu], and [Joseph] at MIT Media Labs have made sensor deployment as easy as unraveling a strip of tape from your toolkit. They’ve developed SensorTape, an unrollable, deployable network of interconnected IMU and proximity sensors packaged in a familiar form factor of a roll of masking tape.

Possibly the most interesting technical challenge in a string of connected sensor nodes is picking a protocol that will deliver appreciable data rates with low latency. For that task the folks at MIT Media labs picked a combination of I²C and peer-to-peer serial. I²C accomodates the majority of transmissions from master to tape-node slave, but addresses are assigned dynamically over serial via inter-microcontroller communication. The net effect is a fast transfer rate of 100 KHz via I²C with a protocol initialization sequence that accommodates chains of various lengths–up to 128 units long! The full details behind the protocol are in their paper [PDF].

With a system as reconfigurable as SensorTape, new possibilities unfold with a solid framework for deploying sensors and aggregating the data. Have a look at their video after the break to get a sense of some of the use-cases that they’ve uncovered. Beyond their discoveries, there are certainly plenty others. What happens when we spin them up in the dryer, lay them under our car or on the ceiling? These were questions we may never have dreamed up because the tools just didn’t exist! Our props are out to SensorTape for giving us a tool to explore a world of sensor arrays without having to trip over ourselves in the implementation details.

via [CreativeApplications]

Continue reading “SensorTape Unrolls New Sensor Deployment Possibilities” →