Training Bats In The Random Forest With The Confusion Matrix

When exploring the realm of Machine Learning, it’s always nice to have some real and interesting data to work with. That’s where the bats come in – they’re fascinating animals that emit very particular ultrasonic calls that can be recorded and analysed with computer software to get a fairly good idea of what species they are. When analysed with an FFT spectogram, we can see the individual call shapes very clearly.

Creating an open source classifier for bats is also potentially useful for the world outside of Machine Learning as it could not only enable us to more easily monitor bats themselves, but also the knock on effects of modern farming methods on the natural environment. Bats feed on moths and other night flying insects which themselves have been decimated in numbers. Even in the depths of the countryside here in the UK these insects are a fraction of the population that they used to be 30 years ago, but nobody seems to have monitored this decline.

So getting back to our spectograms, it would be perfectly reasonable to throw these images at a convolutional neural network (CNN) and use an image feature-recognition strategy. But I wanted to explore the depths of the mysterious Random Forest. Continue reading “Training Bats In The Random Forest With The Confusion Matrix”

Jackpot!: The Trials And Tribulations Of Turning A Slot Machine Into An ATM

Have you ever wished that slot machines dispensed money as easily as an ATM? Well so did [Scotty Allen] from Strange Parts, so in collaboration with his friend [Matt] decided to combine the two. After a four-month journey fraught with magic smoke and frustration, they managed to build a fully functional ATM slot machine.

The basic idea is that you insert your card and enter your pin like on a normal ATM, select your winning amount, and pull the lever. This sets wheels spinning, which come to a stop with three-of-a-kind every time, and you win your own money as a bucket load of coins with all the accompanying fanfare. The project took way longer than [Scotty] expected, and he ended up missing his original deadline to show off the machine at DEF CON.

They started with an old broken Japanese slot machine, and replaced the control board with an Arduino Due after a lot of reverse engineering and hacking. [Scotty] did a cool video just on getting the original vacuum fluorescent display working. Integrating the ATM parts proved to be the biggest challenge, with number of very expensive parts releasing their magic smoke or getting bricked in the process. [Scotty] came up with an ingeniously simple hack to interface the ATM hardware with the Arduino. The cash note dispenser uses multiple sensors to detect if there are notes loaded and if one is successfully dispensed. These were spoofed by the Arduino, which controls two coin hoppers instead to dispense appropriate amount of quarters or pennies. The build was rounded off with some very neat custom graphics on the glass panels, and the machine was finally showed off at a local arcade.

This was an awesome project, and we can appreciate the fact that [Scotty] made no attempt to hide the real emotional roller coaster that anyone who has worked on a large project knows, but is rarely documented in logs. [Scotty] has made a name for himself by building his own iPhone from parts and touring Shenzhen’s many factories. Check out the videos after the break Continue reading “Jackpot!: The Trials And Tribulations Of Turning A Slot Machine Into An ATM”

Print From The ESP8266, Courtesy Of Google

The ESP8266 has become the hacker’s microcontroller of choice because it’s exceptionally easy to get the chip connected to the network and talking to other devices. The fact that it’s also absurdly cheap is just a bonus. Since nearly every piece of electronics you buy today is “smart” enough to include some form of Internet control, that means there’s no shortage of gadgets these MCUs can potentially poke and prod.

In their latest tip, [TecnoProfesor] shows how you can interface the ESP8266 with Google’s Cloud Print, a service that enables simple remote printing over the web without having to worry about having the proper device drivers. Remote printing from the ESP8266 might seem like little more than a gag at first glance, but if you’re the kind of person who likes to have hard copies of data, adding the capability to generate a daily printed report to your weather station could be a nice weekend project.

[TecnoProfesor] provides explanations and source code for printing documents of various sizes from both the ESP8266’s internal flash storage and an SPI-attached SD card. Towards the end of the write-up, there’s even some explanation of how the setPrintDocument() function of the Cloud Print API can be used in more advanced scenarios, such as printing web pages or documents stored in Google Drive.

When we see microcontrollers connected to printers, they’re usually of the small thermal kind. Being able to access “real” printers with such a simple technique offers some interesting possibilities, though like most technology, there’s potential for it to be misused.

[Thanks to Andrew for the tip.]