Investigating the generative properties of a stepper motor

You probably know that if you spin a motor (mechanically) it generates electricity on what would normally be the inputs. This can be a problem when you shut off a spinning motor and is the reason that protection diodes are built into motor driver circuits. But [Dino] isn’t interested in driving a motor, he wanted to see what he could do with the electricity generated by spinning a stepper motor.

He built the test rig that you see above for this purpose. In the foreground a 12V DC motor is held in place with an electrical conduit clamp. This connects to the stepper motor being tested using a segment of rubber tube. The DC motor provides a reliable input for his experiments, but could be replaced in the future by a propeller to make it wind powered, or by a water wheel. Check out the video after the break to see what kind of juice [Dino] gets out of it, and how it can be used for powering LEDs, recharging batteries, or driving a motor.

Continue reading “Investigating the generative properties of a stepper motor”

Espresso upgrade gives you more data with your caffeine

Whether you take it as a single shot or a double, a great Barista want’s to know the details on what’s happening with the espresso machine. [Tobi] was happily generating the morning cup when he realized that the needle-thermometer on his machine wasn’t working any longer. Instead of shelling out a lot of money for a direct replacement, he built his own display and controller for this espresso machine (translated).

He had a few goals with this hack. Obviously he needed to replace the temperature meter, but he also wanted a colorful display and some timing options. He was able to get his hands on a nice little OLED display that would fit in the vacated opening and it only cost a few bucks. He’s got his own mini-mill which came in handy when fabricating a board to host the ATmega16 which drives add-on, but he also used it to make a bracket for the screen replacement.

Now his machine is fixed, looks a bit more modern, and it has more features which are shown off in the video after the break. If you’re looking to add some custom circuitry to your coffee ritual you may also take some inspiration from this similar espresso machine hack. Continue reading “Espresso upgrade gives you more data with your caffeine”

Matrix backpack was a fun design project

[Greg] is really working on a small scale with his LED Matrix backpack PCB. It’s a toy that he designed as an activity. He constrained himself to a board which would exactly match the outline of an 8×8 bicolor LED matrix package.

What you see here is the side of the PCB which will be facing the underside of the LED dot matrix module. Let’s call this the top of the board. The underside has a CR2032 battery holder which provides enough juice to run the display. Since the matrix is bi-color there’s a slew of pins to drive. [Greg] uses three shift registers for the high side, and sixteen N-channel MOSFETS for the low side. He’s chosen an MSP430G2201 microcontroller which has a nice sleep mode for power conservation. It has no problem driving tri-color animations as seen the clip after the break, but also has an unpopulated clock crystal footprint if you wanted to use it as a timepiece.

Despite the small footprints and cramped board [Greg] still hand soldered all of the components. He even posted a time-lapse of the process in the page linked at the top.

Continue reading “Matrix backpack was a fun design project”

Reviewing the numbers from one month of solar harvesting

[Mathieu] just finished analyzing the numbers from a month of solar energy harvesting. You may remember that he was curious to see what kind of energy can be collected from small solar cells used indoors. He built several copies of a test platform which collected data between December 16th and January 16th.

First of all, it’s not shocking to find out that rooms with no sunlight produced negligible energy during that time. When you think about it, if they had been gathering a statistically significant amount wouldn’t that mean the lighting used in those rooms was incredibly inefficient? In other words, there’s no way you need to be making that much light.

But he did find that proper positioning in rooms that catch sunlight during the day can result in usable energy for small loads. He established that a 0.5 Watt panel harvested just a bit more than half of what a 1 Watt panel did. But perhaps the most useful discovery was that it’s quite a bit more efficient to have a charging circuit store energy in a battery rather than directly powering a fixed load.

It will take us a few more viewings to really decide what we can take away from the experiment for our own projects. But we appreciate [Mathieu's] quest for knowledge and his decision to put this information out there so that others can learn from it.

Whac-A-Banker to relieve your frustration

[Tim Hunkin], builder extraordinaire and host of The Secret Life of Machines is a bit frustrated with the current economic climate and decided to take out his frustrations with a game of Whac-A-Banker.

[Tim]‘s version of the classic Whac-A-Mole game uses tiny air cylinders to actuate five banker figurines up and down. The figures were cast with polyurethane and are reportedly holding up well. The cabinet is really interesting. When the game isn’t being played, a really boring front panel is displayed. After inserting a few coins, the panel drops into the machine to show the fun and exciting scoreboard.

If you’re ever around Suffolk, England, you can check out the Whac-A-Banker and a lot of other [Tim Hunkin] creations at the Southwold Pier. Thanks [John] for sending this one in. Yes, we did get The Secret Life of Machines in the states on the Discovery Channel, but it has been replaced with shows about trucking. Here’s an archive of the entire series for your viewing pleasure. Kiss your evening goodbye.

Controlling an LED matrix with an Android phone

Even though everyone with a smart phone has a small, powerful computer in their pocket, we haven’t seen many applications of this portable processing power that use the built-in camera. [Michael] decided to change this and built an LED matrix that displays the data coming from the phone’s camera.

For the build, [Michael] used two 32×32 LED panels from Adafruit along with an IOIO and an Arduino. To build the Android app, [Michael] used the Android OpenCV computer vision library that grabs an image from the Android camera and downsamples it to 64×32 pixels. This data is transferred over a serial connection from the phone to the IOIO and again from the IOIO to the Arduino. Even though each frame is 1024 bytes, [Michael] still gets around four frames per second on his LED matrix display.

After the break you can check out the results of [Michael]‘s build. The video is a little choppy because of the frame rate issue, but it’s still an interesting build in the Android software development category.

Continue reading “Controlling an LED matrix with an Android phone”

Maximite harkens back to the days of BASIC

Any self-identified geek that spent some time in the 80s will tell you how they used to type out programs into their ‘microcomputer’ with BASIC. It was a simpler time when a computer’s raison d’etre was simply being a BASIC interpreter. These days are long past us now; you can’t simply turn on a computer and have it load a BASIC prompt anymore. This is where [Geoff]‘s Maximite single board computer comes in. It’s a tiny little box that whose only purpose is to play around with BASIC.

[Geoff]‘s used a PIC32MX microcontroller with 128k of RAM for the CPU of his Maximite. Unlike an Apple ][ or TRS-80, the Maximite version of BASIC can do floating point arithmetic out of the box. To connect to the outside world, the Maximite has VGA or composite out to display the BASIC interepreter. A PS/2 keyboard port provides the input, and a USB port and SD card can be used to load and save programs from a PC.

The Maximite includes a 20-pin breakout for whatever IO you can imagine. This is duplicated on [Geoff]‘s mini Maximite that is designed to be the retro throwback of an Arduino. We though those were called BASIC stamps, but if it gets kids programming, we’ll let it slide.