This week Jonathan Bennett and Rob Campbell talk with Gareth Coleman and Hamish Cunningham! It’s all about the Unphone, an open source handset sporting an ESP32, color touchscreen, and LoRa radio. It’s open hardware, and used in a 3rd year university course to teach comp sci majors about hardware and embedded development.
Continue reading “FLOSS Weekly Episode 783: Teaching Embedded With The Unphone”
Camera sliders are great creative tools, letting you get smooth controlled shots that can class up any production. [Anthony Kouttron] decided to build one for an engineering class, and he ended up mighty satisfied with what he and his team accomplished.
As an engineering class project, this wasn’t a build done on a whim. Instead, [Anthony] and his fellow students spent plenty of time hashing out what they needed this thing to do, and how it should be built. An Arduino was selected as the brains of the operation, as a capable and accessible microcontroller platform. Stepper motors and a toothed belt drive were used to move the slider in a controllable fashion. The slider’s control interface was an HD44780-based character LCD, along with a thumbstick and two pushbuttons. The slider relied on steel tubes for a frame, which was heavy, but cost-effective and easy to fabricate. Much of the parts were salvaged from legendary e-waste bins on the university grounds.
The final product was stout and practical. It may not have been light, but the steel frame and strong stepper motor meant the slider could easily handle even heavy DSLR cameras. That’s something that lighter builds can struggle with.
Ultimately, it was an excellent learning experience for [Anthony] and his team. As a bonus, he got some great timelapses out of it, too. Video after the break.
Continue reading “Designing A Quality Camera Slider Can Be Remarkably Satisfying”
Have you ever tried to eat one jelly bean or one potato chip? It is nearly impossible. Some of us have the same problem with hardware projects. It all started when I wrote about the old bitslice chips people used to build computers before you could easily get a whole CPU on a chip. Bitslice is basically Lego blocks that build CPUs. I have always wanted to play with technology, so when I wrote that piece, I looked on eBay to see if I could find any leftovers from this 1970-era tech. It turns out that the chips are easy to find, but I found something even better. A mint condition AM2900 evaluation board. These aren’t easy to find, so the chances that you can try one out yourself are pretty low. But I’m going to fix that, virtually speaking.
This was just the second potato chip. Programming the board, as you can see in the video below, is tedious, with lots of binary switch-flipping. To simplify things, I took another potato chip — a Google Sheet that generates the binary from a quasi-assembly language. That should have been enough, but I had to take another chip from the bag. I extended the spreadsheet to actually emulate the system. It is a terrible hack, and Google Sheets’ performance for this sort of thing could be better. But it works.
Continue reading “A Slice Of Simulation, Google Sheets Style”
Operating systems! They’re everywhere these days, from your smart TV to your smartphone. And even in your microcontrollers! Enter BreadboardOS for the Raspberry Pi Pico.
BreadboardOS is built on top of FreeRTOS. It’s aim is to enable quick prototyping with the Pi Pico. Don’t confuse operating system with a graphical environment — BreadboardOS is command-line based. You’d typically interface with it via a serial terminal emulator, but joy of joys, it does support color!
Using BreadboardOS is a little different than typical microcontroller development. Creating an application involves adding a “service” which is basically a task in FreeRTOS parlance. The OS handles running your service for you. Via the text interface, you can query running services, and start or kill them at will.
Meanwhile, running df will happily give you stats on the flash usage of the Pi Pico, and free will tell you how full the memory is doing. If you really want to get raw, you can make calls to control GPIO pins, the SPI hardware, or other peripherals, and do it right on the command line.
BreadboardOS isn’t for everyone, but it could prove a useful tool if you like that way of doing things. It’s not the only OS out there for the Pi Pico, either!
Continue reading “BreadboardOS, A Command Line Interface For The Pico”
These days, you can get a fully remote-control helicopter that you can fly around your house for about $30. Maybe less. Back in the day, kids had to make do with far simpler toys, like spinning discs that just flew up in the air. [JBV Creative] has built a toy just like that with his 3D printer. It may be simple, but it also looks pretty darn fun.
The design is straightforward. It uses a power drill to spin up a geartrain, which in turn drives a small disc propeller. Spin the propeller fast enough and it’ll launch high into the air. The geartrain mounts to the drill via the chuck, and it interfaces with the propeller with a simple toothed coupler. Alternatively, there’s also a hand-cranked version if you don’t have a power drill to hand.
Launching is easy. First, the drill spins the propeller up to speed. Then, when the drill’s trigger is released, it slows down, and the propeller spins free of the toothed coupler, with the lift it generates carrying it into the sky.
Files are available online for those interested. We could imagine this toy could make the basis for a great design competition. Students could compete to optimise the design with more effective gear ratios or better airfoils. We’ve seen similar designs before, too. Video after the break.
Continue reading “3D Print A Drill-Powered Helicopter Toy Because It’s Simply Fun”
The Apple II was launched in 1977, a full 47 years ago. The Apple IIe came out six years later, with a higher level of integration and a raft of new useful features. Apple eventually ended production of the whole Apple II line in 1993, but that wasn’t the end. People like [James Lewis] are still riffing on the platform to this day. Even better, he came to Supercon 2023 to tell us all about his efforts!
[James]’s talk covers the construction of the Mega IIe, a portable machine of his own design. As the name suggests, the project was based on the Mega II chip, an ASIC for which he had little documentation. He wasn’t about to let a little detail like that stop him, though.
The journey of building the Mega IIe wasn’t supposed to be long or arduous; the initial plan was to “just wire this chip up” as [James] puts it. Things are rarely so simple, but he persevered nonetheless—and learned all about the Apple II architecture along the way.
Continue reading “Supercon 2023: Building The Ultimate Apple IIe, Decades Later”
As [Electronoobs] points out, everything has resistance. So, how hard can it be to make a high-power resistor? In the video below, he examines a commercial power resistor and how to make your own using nichrome wire.
Sure, in theory, you can use a long piece of wire, but normally, you want to minimize the amount of space occupied. This leads to winding the wire around some substrate. If you just wind the wire, though, you get an inductor. This can cause nasty voltage spikes when there is a change in current through the resistor. You can get “noninductive” wire wound resistors that use either two opposing windings or alternate the turn direction on each turn. This causes the magnetic fields to tend to cancel out, reducing the overall inductance.
Nichrome wire has more resistance per millimeter and can dissipate more power. Modern digital meters can measure the resistance of a wire if you account for the test leads. To make a substrate, [Electronoobs] got creative since he anticipated generating a lot of heat. The final product even uses water cooling.
Why do you want a big resistor? Maybe you need a dummy load, or you want to drain some batteries. If you want to recycle nichrome wire, it is much more common than you might expect.
