Visualizing Ballet Movements with E-Traces

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.

WiFi Power Monitor

Building your own hardware to measure AC power isn’t a simple task. There’s a number of things to measure, including voltage, current, power, and power factor. The Atmel 90E24 is a single chip solution designed for this exact purpose. Connect a few components, and all the power data is available to a microcontroller over SPI.

[hwstar] built a custom power monitoring board based on this IC. His AC-Emeter will give you all the measurements you’d want, and includes an ESP12 module for data collection and WiFi connectivity. Aside from the Atmel 90E24 device, a high power and low resistance resistor is needed for shunt sense current measurement. An external module is used to convert mains voltage down to 5V to power the board.

Of course, working with mains voltages can be a dangerous endeavour. Fortunately, [hwstar] provides some tips on how to prevent “equipment from being BLOWN UP” along with the open source hardware and firmware.

[via Embedded Lab]

Novation Launchpad MIDI Controller Moves Toward Open Source

The Novation Launchpad is a MIDI controller, most commonly used with the Ableton Live digital audio workstation. It’s an eight by eight grid of buttons with RGB LED backlights that sends MIDI commands to your PC over USB. It’s often used to trigger clips, which is demonstrated by the artist Madeon in this video.

The Launchpad is useful as a MIDI input device, but that’s about all it used to do. But now, Novation has released an open source API for the Novation Pro. This makes it possible to write your own code to run on the controller, which can be flashed using a USB bootloader. An API gives you access to the hardware, and example code is provided.

[Jason Hotchkiss], who gave us the tip on this, has been hacking around with the API. The Launchpad Pro has a good old 5 pin MIDI output, which can be connected directly to a synth. [Jason]’s custom firmware uses the Launchpad Pro as a standalone MIDI sequencer. You can check out a video of this after the break.

Unfortunately, Novation didn’t open source the factory firmware. However, this open API is a welcome change to the usual closed-source nature of audio devices.

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A Better Spectrum Analyzer for your Rigol Scope

The Rigol DS1000 series of oscilloscopes are popular with hobbyists for good reason: they provide decent specs at a low price. However, their spectrum analysis abilities are lacking. While these scopes do have a Fast Fourier Transform (FFT) function, it’s limited and nearly useless for RF.

A FFT plotted by the PyDSA tool and a Rigol oscilloscope[Rich] wanted a spectrum analyzer for amateur radio purposes, but didn’t want to build his own sampling hardware for it. Instead, he wrote PyDSA, a software spectrum analyzer for Rigol DS1000 oscilloscopes. This tool uses the USB connection on the scope to fetch samples, and does the number crunching on a far more powerful PC. It’s able to plot a 16,000 point FFT at two sweeps per second when run on a decent computer.

PyDSA is a Python script that makes use of the Virtual Instrument Software Architecture (VISA) interface to control the scope and fetch the sample data. Fortunately there’s some Python libraries that take care of the protocol.

[Rich] is now able to use his scope to measure amateur radio signals, which makes a nice companion to his existing Teensy based SDR project. If you have a Rigol, you can grab the source on Github and try it out.

The Year of the Car Hacks

With the summer’s big security conferences over, now is a good time to take a look back on automotive security. With talks about attacks on Chrysler, GM and Tesla, and a whole new Car Hacking village at DEF CON, it’s becoming clear that autosec is a theme that isn’t going away.

Up until this year, the main theme of autosec has been the in-vehicle network. This is the connection between the controllers that run your engine, pulse your anti-lock brakes, fire your airbags, and play your tunes. In most vehicles, they communicate over a protocol called Controller Area Network (CAN).

An early paper on this research [PDF] was published back in 2010 by The Center for Automotive Embedded Systems Security,a joint research effort between University of California San Diego and the University of Washington. They showed a number of vulnerabilities that could be exploited with physical access to a vehicle’s networks.

A number of talks were given on in-vehicle network security, which revealed a common theme: access to the internal network gives control of the vehicle. We even had a series about it here on Hackaday.

The response from the automotive industry was a collective “yeah, we already knew that.” These networks were never designed to be secure, but focused on providing reliable, real-time data transfer between controllers. With data transfer as the main design goal, it was inevitable there would be a few interesting exploits.

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Hacking a $100 Signal Generator

Signal generators are a useful piece of kit to have on your electronics bench. The downside is that they tend to be rather expensive. If you have $100 to drop on a new toy, the MHS-5200A is a low cost, two channel, 25 MHz generator that can be found on eBay.

The downside is the software. It’s an ugly Windows interface that’s a pain to use. The good news is that [wd5gnr] reverse engineered the protocol so you don’t have to. This means other software can be developed to control the device.

When connected to a computer, this function generator shows up as a virtual USB serial port. The documentation that [wd5gnr] assembled lists all the serial commands you can send, and what they do. If you aren’t into manually setting waveforms from a serial terminal (who is?) there’s a tool for doing that automatically on Github. This takes in a CSV file describing a waveform, and programs the generator to make it for you.

The software is also compatible with Waveform Manager Plus, a free GUI tool for defining waveforms. Putting this all together, you can have a pretty capable waveform generator for less than $100.

Wirelessly Weighing Plants with the ESP8266

There’s a good number of hacks, and commercial products, for telling you when a plant needs watering. Most of them use an ADC to measure the resistance in the soil. As the soil’s moisture content drops, the resistance increases. High impedance, dead plant.

[Dani]’s Thirsdee takes a different approach to plant health monitoring. Instead of measuring resistance, it simply weighs the plant. As the soil dries up, it gets lighter. By measuring the change in weight, the amount of water in the pot can be estimated.

Thirsdee uses a load cell to measure the weight. It’s read using an HX711 ADC, which is controlled by a NodeMCU. This development board is based on the ESP8266 chip. Since Thirsdee has WiFi, it can push notifications to your phone and log data on ThingSpeak. If you’re looking at the plant, an OLED shows you the current status of the plant. For us viewing from home, we can see a graph of [Dani]’s plant drying out in real time.

[Dani] provides us with a list of suppliers for the parts, and all the source code on Github.