Liquid Lite Brite Robot

March 3, 2021 by Bryan Cockfield 2 Comments

Liquid handling workstations are commonly used in drug development, and look like small CNC machines with droppers on the ends which can dispense liquid into any container in a grid array. They are also extraordinarily expensive, as is most specialty medical research equipment. This liquid handling workstation doesn’t create novel drugs, though, it creates art, and performs similar functions to its professional counterparts at a much lower cost in exchange for a lot of calibration and math.

The art is created by pumping a small amount of CMYK-colored liquids into a 24×16 grid, with each space in the grid able to hold a small amount of the colored liquid. The result looks similar to a Lite-Brite using liquids instead of small pieces of plastic. The creator [Zach Frew] created the robot essentially from scratch using an array of 3D printers, waterjets, and CNC machines. He was able to use less expensive parts, compared to medical-grade equipment, by using servo-controlled valves and peristaltic pumps, but makes up for their inaccuracies with some detailed math and calibration.

The results of the project are striking, especially when considering that a lot of hurdles needed to be cleared to get this kind of quality, including some physical limitations on the way that the liquids behave in the first place. It’s worth checking out not just for the art but for the amount of detail involved as well. And, for those still looking to scratch the 90s nostalgia itch, there are plenty of other projects using the Lite Brite as inspiration.

Thanks to [Thane Hunt] for the tip!

Free To Good Home: FPGA Supercharged Audio/Video Synthesizer

March 3, 2021 by Bryan Cockfield 10 Comments

Audio and video synthesizers have been around for decades, and are pretty much only limited by one’s willingness to spend money on them. That is, unless you can develop your own FPGA-supercharged synthesizer to really get a leg up on the consumer-grade components. Of course, as [Julian] found out in this four-year project, you tend to pay for it anyway in time spent working on your projects.

[Julian] has actually decided to stop working on the project and open-source it to anyone who wants to continue on. He has already finished the PCB layout on a gargantuan 8-layer print, done all of the routing and parts selection, and really only needed to finish testing it to complete the project. It’s powered by the Xilinx Zynq and is packed with features too: HDMI, DDR3 ram, USB, a handful of sensors, and an Arduino Uno-style header to make interfacing and programming a breeze.

While we’re sympathetic with setting aside a project that we’ve worked so hard on, with most of the work done on this one it should be pretty easy to pick up and adapt for anyone interested in carrying the torch. If you were hoping to wet your whistle with something with fewer PCB layers, though, we’ve seen some interesting (but slightly simpler) video synthesizers made out of other unique hardware as well.

Circuit Impedance Calculations Without Cumbersome Simulations

March 2, 2021 by Bryan Cockfield 11 Comments

Using circuit simulating software like SPICE can be a powerful tool for modeling the behavior of a circuit in the real world. On the other hand, it’s not always necessary to have all of the features of SPICE available all the time, and these programs tend to be quite expensive as well. To that end, [Wes Hileman] noticed an opportunity for a specific, quick method for performing impedance calculations using python without bulky, expensive software and came up with a program which he calls fastZ.

The software works on any network of passive components (resistors, capacitors, and inductors) and the user can specify parallel and series connections using special operators. Not only can the program calculate the combined impedance but it can perform frequency analysis at a specified frequency or graph the frequency response over a wide range of frequencies. It’s also running in python which makes it as simple as importing any other python package, and is also easy to implement in any other python program compared to building a simulation and hoping for the best.

If you find yourself regularly drawing Bode plots or trying to cobble together a circuit simulation to work with your python code, this sort of solution is a great way to save a lot of headache. It is possible to get the a piece of software like SPICE to to work together with other python programs though, often with some pretty interesting results.

Street-Legalize Your Ebike With A Magnet

March 1, 2021 by Bryan Cockfield 98 Comments

Getting into e-biking is a great hobby. It can get people on bikes who might otherwise not be physically able to ride, it can speed up commute times, and it can even make hauling lots of stuff possible and easy, not to mention it’s also fun and rewarding. That being said, there are a wide array of conflicting laws around what your e-bike can and can’t do on the road and if you don’t want to run afoul of the rules you may need a programmable device that ensures your e-bike is restricted in the appropriate way.

This build is specifically for Bafang mid drives, which can be up to 1000 W and easily power a bike beyond the speed limit where [Tomblarom] lives. A small microcontroller is housed in a waterproof box on the bike and wired between the motor’s display and controller. A small hall effect sensor and magnet sit by this microcontroller, and if the magnet is removed then the microcontroller reprograms the bike’s controller to limit the speed and also to disable the throttle, another feature that is illegal in some jurisdictions but not others. As an added bonus, the microcontroller also handles brake lights, turn signals, and automatic headlights for the bike as well.

While the project page mentions removing the magnet while getting pulled over to avoid fines and other punishments, that’s on you. We imagine this could still be useful for someone who wants to comply with local laws when riding on the road, but still wants to remove the restrictions when riding on private property or off-road where the wattage and speed restrictions might not apply.

Wind Turbines And Ice: How They’re Tailored For Specific Climates

March 1, 2021 by Bryan Cockfield 75 Comments

Wind turbines are incredible pieces of technology, able to harvest wind energy and deliver it to the power grid without carbon emissions. Their constant development since the first one came online in 1939 mean that the number of megawatts produced per turbine continues to rise as price per megawatt-hour of wind energy continues to fall. Additionally, they can operate in almost any climate to reliably generate energy almost anywhere in the world from Canada to the North Atlantic to parts beyond. While the cold snap that plowed through the American South recently might seem to contradict this fact, in reality the loss of wind power during this weather event is partially a result of tradeoffs made during the design of these specific wind farms (and, of course, the specifics of how Texas operates its power grid, but that’s outside the scope of this article) rather than a failure of the technology itself.

First, building wind turbines on the scale of megawatts isn’t a one-size-fits-all solution. Purchasing a large turbine from a company like GE, Siemens, or Vestas is a lot like buying a car. A make and model are selected first, and then options are selected for these base models. For example, low but consistent wind speeds demand a larger blade that will rotate at a lower speed whereas areas with higher average wind speeds may be able to get by with smaller and less expensive blades for the same amount of energy production. Another common option for turbines is cold weather packages, which include things like heaters for the control systems, hydraulics, and power electronics, additional insulation in certain areas, and de-icing solutions especially for the turbine blades.

In a location like Texas that rarely sees cold temperatures for very long, it’s understandable that the cold weather packages might be omitted to save money during construction (although some smaller heaters are often included in critical areas to reduce condensation or humidity) but also to save on maintenance as well: every part in a wind turbine has to be maintained. Continuing the car analogy, it’s comparable to someone purchasing a vehicle in a cold climate that didn’t come equipped with air conditioning to save money up front, but also to avoid repair costs when the air conditioning eventually breaks. However, there are other side effects beyond cost to be considered when installing equipment that’s designed to improve a turbine’s operation in cold weather.

Let’s dig into the specifics of how wind turbine equipment is selected for a given wind farm.

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Electroplating 3D Printed Parts For Great Strength

March 1, 2021 by Bryan Cockfield 33 Comments

Resin 3D printers have a significant advantage over filament printers in that they are able to print smaller parts with more fine detail. The main downside is that the resin parts aren’t typically as strong or durable as their filament counterparts. For this reason they’re often used more for small models than for working parts, but [Breaking Taps] wanted to try and improve on the strength of these builds buy adding metal to them through electroplating.

Both copper and nickel coatings are used for these test setups, each with different effects to the resin prints. The nickel adds a dramatic amount of stiffness and the copper seems to increase the amount of strain that the resin part can tolerate — although [Breaking Taps] discusses some issues with this result.

While the results of electroplating resin are encouraging, he notes that it is a cumbersome process. It’s a multi-step ordeal to paint the resin with a special paint which helps the metal to adhere, and then electroplate it. It’s also difficult to ensure an even coating of metal on more complex prints than on the simpler samples he uses in this video.

After everything is said and done, however, if a working part needs to be smaller than a filament printer can produce or needs finer detail, this is a pretty handy way of adding more strength or stiffness to these parts. There’s still some investigating to be done, though, as electroplated filament prints are difficult to test with his setup, but it does show promise. Perhaps one day we’ll be able to print with this amount of precision using metal directly rather than coating plastic with it.

Thanks to [smellsofbikes] for the tip!

Continue reading “Electroplating 3D Printed Parts For Great Strength” →

Reliable Frequency Reference From GPS

February 28, 2021 by Bryan Cockfield 35 Comments

GPS technology is a marvel of the modern world. Not only can we reliably locate positions on the planet with remarkable accuracy and relatively inexpensive hardware, but plenty of non-location-based features of the technology are available for other uses as well. GPS can be used for things like time servers, since the satellites require precise timing in order to triangulate a position, and as a result they can also be used for things like this incredibly accurate frequency reference.

This project is what’s known as a GPSDO, or GPS-disciplined oscillator. Typically they use a normal oscillator, like a crystal, and improve its accuracy by pairing it with the timing signal from a GPS satellite. This one is a standalone model built by [Szabolcs Szigeti] who based the build around an STM32 board. The goal of the project was purely educational, as GPSDOs of various types are widely available, but [Szabolcs] was able to build exactly what he wanted into this one including a custom power supply, simple standalone UI, and no distribution amplifier.

The build goes into a good bit of detail on the design and operation of the device, and all of the PCB schematics and source code are available on the projects GitHub page if you want to build your own. There are plenty of other projects out there that make use of GPS-based time for its high accuracy, too, like this one which ties a GPS time standard directly to a Raspberry Pi.