Direct conversion receivers are popular among ham radio operators and others who build radios. Suppose you want to listen to a signal at 7.1 MHz. With a direct conversion receiver, you’d tune a local oscillator to 7.1 MHz, and mix it with the incoming signal. The resulting sum and differences of the input frequencies will include the audio of an AM signal on the desired frequency.
Continue reading “Polyakov Direct Digital Synthesis Receiver”
There are a surprising number of Raspberry Pis being used in industrial equipment. This means the Arduino is left behind, but no longer. There’s your PLCs that use Arduinos.
A few weeks ago, Google introduced a machine intelligence and computer vision technique that made the world look psychedelic. Now, this library is available. On another note, head mounted displays exist, and a sufficiently creative person could mash these two things together into a very, very cool project.
Welcome to Kickstarter! Kickstarter is an uphill battle. People will doubt you because you don’t have a ‘target audience’ or ‘the rights to this franchise’ or ‘any talent whatsoever’, but that’s what crowdfunding is for!
Several years ago, Apple shipped a few million 17″ iMacs with defective displays. They’re still useful computers, though, especially if you can find a replacement LCD. Apple, in all its wisdom, used a weird connector for this LCD. Here’s the adapter board, and this adapter will allow displays running up to 1920×1200.
[Jan] has earned a reputation of building some very cool synths out of single ARM chips. His previous build was a Drumulator and now he’s shrinkified it. He’s put four drum sounds, pitch CV, and audio out on an 8-pin DIP ARM.
YouTube gives you cadmium! [AvE], recently got 100,000 subscribers on his YouTube channel. Apparently, YouTube sends you a terrible belt buckle when you manage to do that. At least he did it without playing video games and screaming.
Several years ago, [Cameron] added an ATMega328-based PID temperature controller to his espresso machine. It has performed admirably to this day. But behind that cool bezel and LCD, all of the electronics are just sitting there, exposed. [Cameron] decided to give it a makeover. He has a better machine at home these days and wanted to take the old one to work. In order to keep untrained hands away from it in the office’s shared kitchen, [Cameron] installed a 4-digit keypad.
This makeover didn’t end with hiding wires and locking out noobs, though. [Cameron] added a float switch that will disable the pump when the water level gets too low. This is a nice touch. Otherwise, machines like this one will try to brew when the tank is dry, and then the pump has to be primed once the tank is refilled. [Cameron] also replaced the buttons’ back-lighting bulbs with bright LEDs. A small LCD mounted on the front of the machine shows the boiler temperature and shot-pulling duration.
If you’ve add PID temperature control to your espresso machine but have done nothing to improve the steam wand, why not add a pressure gauge?
If you want to make a submersible robot (or, really, any robot) you can either design it for a specific mission, or you can try to make it general purpose. The researchers at the Cura Oceanus Foundation opted for the latter approach with RiverBot, a community-designed unmanned submersible.
Comparing it to the Space Shuttle, the RiverBot has payload bays that accept sensor kits or custom-made payloads. The builders hope to provide a platform for students and others and want to have students start with RiverBot in middle school, and keep working with the program all the way up to the PhD level.
When we think of wearable technologies, ballet shoes aren’t the first devices that come to mind. In fact, the E-Traces pointé shoes by [Lesia Trubat] may be the first ever “connected ballet shoe.” This project captures the movement and pressure of the dancer’s feet and provides this data to a phone over Bluetooth.
The shoes are based on the Lilypad Arduino clone, which is designed for sewing into wearables. It appears that 3 force sensitive resistors are used as analog pressure sensors, measuring the force applied on the ground by the dancer’s feet. A Lilypad Accelerometer measures the acceleration of the feet.
This data is combined in an app running on an iPhone, which allows the dancer to “draw” patterns based on their dance movements. This creates a video of the motion based on the dance performed, and also collects data that can be used to analyze the dance movements after the fact.
While these shoes are focused on ballet, [Lesia] points out that the same technique could be extended to other forms of dance for both training and visualization purposes.
You know Processing? It is the programming language and IDE aimed at the electronic arts, new media art, and visual design communities. [Gottfried Haider] recently got Processing working on the Raspberry Pi and included a hardware input/output library to manipulate the Pi’s I/O pins.
If you want to experiment with Processing, you can download it right on your Pi with the following command:
curl https://processing.org/download/install-arm.sh | sudo sh
You can also download it from the download page. There’s a specific tutorial available or you can watch some general videos on Processing (see below).
[Vadim] wrote up this short but sweet tutorial on getting started with the Vocore (tiny) OpenWRT-router-on-a-stamp. If you need more computing power than you can get with an ESP8266, and you want an open-source Linux-plus-Wifi solution in a square inch of board space, the Vocore looks pretty sweet.
We covered the Vocore a while ago. It has 28 GPIOs, all accessible from system calls in OpenWRT. It becomes much more computer-like if you add a dock that breaks out the USB and Ethernet functionality, but that also doubles the price.
Getting started with a no-frills Linux box (chip?) can be intimidating. So it’s a good thing that [Vadim] details a first setup of the Vocore over WiFi and SSH, and then takes you through a button-and-LED style ‘Hello World’ application that makes simple use of the GPIOs.
He says he’s going to interface it eventually with a TI CC110 sub-gig radio unit, but that’s going to involve writing some drivers and will take him some time. We’d love to see how to connect peripherals, so we’re waiting with bated breath.
[Vadim] also helpfully included an un-bricking script for the Vocore, which restores the default firmware and gets you out of whatever hole you’ve managed to dig yourself into. Basically, you connect to the device over a USB-Serial adapter, run his script, and you should be set.
Any of you out there using a Vocore? Or other OpenWRT routers? Give [Vadim]’s tutorial a glance and let us know what you think.
