Liquid Lite Brite Robot

March 3, 2021 by 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!

Using Phase Change Materials For Energy Storage

March 3, 2021 by 35 Comments

Renewable energy sources are becoming increasingly popular. However, such energy can be wasted if an excess is available when it’s not yet needed. A particularly relevant example is solar power; solar panels provide most of their output during the day, while often a household’s greatest energy use is at night.

One way to get around this problem is by storing excess energy so that it can be used later. The most common way this is done is with large batteries, however, it’s not the only game in town. Phase change materials are proving to be a useful tool to store excess energy and recover it later – storing energy not as electricity, but as heat. Let’s take a look at how the technology works, and some of its most useful applications. Continue reading “Using Phase Change Materials For Energy Storage” →

Attack Of The Flying 18650s

March 3, 2021 by 31 Comments

When somebody builds a quadcopter with the express purpose of flying it as fast and aggressively as possible, it’s not exactly a surprise when they eventually run it into an immovable object hard enough to break something. In fact, it’s more like a rite of passage. Which is why many serious fliers will have a 3D printer at home to rapidly run off replacement parts.

Avid first person view (FPV) flier [David Cledon] has taken this concept to its ultimate extreme by designing a 3D printable quadcopter that’s little more than an 18650 cell with some motors attached. Since the two-piece frame can be produced on a standard desktop 3D printer in a little over two hours with less than $1 USD of filament, crashes promise to be far less stressful. Spend a few hours during the week printing out frames, and you’ll have plenty to destroy for the weekend.

While [David] says the overall performance of this diminutive quadcopter isn’t exactly stellar, we think the 10 minutes of flight time he’s reporting on a single 18650 battery is more than respectable. While there’s still considerable expense in the radio and video gear, this design looks like it could be an exceptionally affordable way to get into FPV flying.

Of course, the argument could be made that such a wispy quadcopter is more likely to be obliterated on impact than something larger and commercially produced. There’s also a decent amount of close-quarters soldering involved given the cramped nature of the frame. So while the total cost of building one of these birds might be appealing to the newbie, it’s probably a project best left to those who’ve clocked a few hours in on the sticks.

We’ve seen quite a few 3D printed quadcopter frames over the years, but certainly none as elegant as what [David] has created here. It’s an experiment in minimalism that really embraces the possibilities afforded by low-cost desktop 3D printing, and we wouldn’t be surprised to see it become the standard by which future designs are measured.

Free To Good Home: FPGA Supercharged Audio/Video Synthesizer

March 3, 2021 by 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.

 

The 70s Are Calling To Shed Some Light

March 2, 2021 by 24 Comments

Remember when phones didn’t all look the same? We had a good thing going in the early cell phone days, which seemed like a brief holdover from the Western Electric (et. al) era where you could get a phone that suited your inner minimalist or princess, and choose the color to boot.

[Dubchinsky] found a beautiful phone from this bygone era and saved it from one of two likely fates — the landfill, or else a life languishing as a piece of vintage technology that’s just sitting around for looks. Instead, this phone found a second calling as a lovely desk lamp with secret goose neck flexibility. The lamp itself is an inexpensive LED module from ebay that’s wired up to mains power through a push button switch in the phone’s base.

We absolutely love that [Dubchinsky] wrapped the curly cord around the goose neck, but were a bit disappointed that he didn’t use the hook switch to turn the lamp on and off. In the comments, he says that the plastic felt like it was too brittle to stand up to repeated actuation of such a heavy switch. That’s understandable. [Dubchinsky] also thought about using the rotary dial as a dimmer, and we think that’s a bright idea.

Between the guide, the pictures, and the build process video after the break, this is pretty much a complete how-to. We think that is commendable given that [Dubchinsky] is selling these lamps on etsy.

Do ya miss spinning the rotary dial and long for somewhat simpler days? Hook your finger into this rotary cell phone.

Continue reading “The 70s Are Calling To Shed Some Light” →

Circuit Impedance Calculations Without Cumbersome Simulations

March 2, 2021 by 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.

Cycling Cadence Display With ESP32

March 2, 2021 by 9 Comments

Terry Pratchett once said “Wisdom comes from experience. Experience is often a result of lack of wisdom.” This is as true with technical skills as it is with the rest of life, and you won’t truly understand a specific topic unless you’ve struggled with it a bit. [publidave] wanted a simple wireless display for a bluetooth cycling cadence sensor, and soon found himself deep down the rabbit hole of Micropython and Bluetooth Low Energy on the ESP32.

[publidave] had converted his bicycle for indoor training during lockdown and winter, and realized he can’t use the guided training app and view his cadence simultaneously, so he needed a dedicated cadence display. Since [publidave] was comfortable with Python, he decided to give Micropython on the ESP32 ago. Bluetooth Low Energy can be rather confusing if you haven’t implemented it before, especially if good examples are hard to come by. In short, the ESP32 needs to find the sensor, connect to it, select the right service, and listen for the notifications containing the data. The data is then converted to RPM and displayed on a small OLED display. [publidave] does an excellent job of describing what exactly he did, highlighting the problems he encountered, and how he solved them.

In the end, he had a functional display, a good idea of what he would do differently next time, and a lot of additional knowledge and understanding. In our book that’s a successful project.

Since so much of the health related devices work with Bluetooth Low Energy, it could be handy to know the technology and how to interface with it. It would allow you to do things like unbrick a $2000 exercise bike,