BORAT: Bathroom Monitor For The Future

October 13, 2014 by Adam Fabio 32 Comments

A recent company move has left [kigster] and his 35 coworkers in a frustrating situation. Their new building only has two single occupancy bathrooms. To make matters worse, the bathrooms are located on two different floors. Heading to one bathroom, finding it occupied, then running upstairs to find the second bathroom also occupied became an all to common and frustrating occurrence at the office.

It was obvious the office needed some sort of bathroom occupancy monitoring system – much like those available on commercial aircraft. [kigster] asked for a budget of about $200 to build such a system. His request was quickly granted it by office management. They must have been on their way to the bathroom at the time.

[kigster] began work on BORAT: Bathroom Occupancy Remote Awareness Technology. The initial problem was detecting bathroom occupancy. The easiest method would be to use door locks with embedded switches, much those used in aircraft. Unfortunately, modifying or changing the locks in a rented office space is a big no-no. Several other human detection systems were suggested and rejected. The final solution was a hybrid. Sonar, Passive Infrared (PIR), and light sensors work in concert to detect if a person is in the bathroom. While we think the final “observer unit” is rather cool looking, we’re sure unsuspecting visitors to the office may be wondering why a two eyed robot is staring at them on the throne.

The display side of the system was easy. The entire system communicates with the venerable nRF24L01+ radio modules, so the display just needed a radio module, an arduino, and a way of displaying bathroom status. Two LED matrices took care of that issue.

We really like this hack. Not only is it a great use of technology to solve a common problem, but it’s also an open source system. BORAT’s source code is available on [kigster’s] github.

Want to know more about BORAT? Kigster is answering questions over on his thread in the Arduino subreddit.

A Simple Floppy Music Controller

October 12, 2014 by Ethan Zonca 12 Comments

While playing music with floppy drives has been done many times over, making any device with a stepper motor play music still appeals to the hacker in all of us. [Tyler] designed an Arduino shield and a library which lets you get up and running in no time. [Tyler]’s shield includes pin headers to connect 4 floppy drives, which plug directly into the shield. The drives don’t need any modification before being used.

While you could simply wire a few floppy drives up to an Arduino with some jumpers, this breakout shield makes connecting your drives trivial. In addition to designing the shield, [Tyler] released an Arduino library to make things even easier. The library lets you simply set the frequency you want each drive to play, which saves a bit of legwork.

The floppy-controlling Arduino library is available on GitHub and a video of the controller is included after the break.

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Build Your Own Stand Alone Web Radio

October 11, 2014 by Sarah Petkus 11 Comments

If you’re the type who enjoys passing idle time by keeping up with podcasts or listening to web stations but don’t always want to occupy your laptop or tablet, this Arduino based radio player will provide a base station for tunes.

The Web Radio project by [Vassilis Serasidis] outlines in a pleasing amount of detail exactly how to wire up a short list of four modules. These including an Ethernet shield, LCD screen, MP3 decoder, and USB serial converter, with an Arduino Mini in order to bookmark and play fourteen of your favorite channels. His hand-soldered board couples everything into one neatly stacked package. The instructional video shows this off and he even explains how to locate your favorite stations on internet-radio.com and copy their port and IP number directly into an example sketch which is provided for use. If you’ve been wanting to build a self contained radio node for your desk free of extra baggage, this is a no-sweat project for both the hardware savvy and those more oriented with code writing.

If you’re going to build your own radio, it’s always cool to disguise your high-tech creation as something more rustic. Check out this project by [Dominic Buchstaller] for a great example of a vintage radio given a second calling.

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Breadboard Circuit of a Funduino, a DS18B20 Temperature Sensor, and an ESP8266 module.

Keep An Eye On Your Fermenting Beer With BrewMonitor

October 11, 2014 by Theodora Fabio 6 Comments

The art of brewing beer is as old as civilization itself. Many people enjoy brewing their own beer at home. Numerous steps must be taken before you can take a swig, but fermentation is one of the most critical. [Martin Kennedy] took up the hobby with his friends, and wanted a convenient way to monitor the fermentation temperature remotely. He started working on the BrewMonitor, a cloud-based homebrewing controller powered by an Arduino clone.

His goal was to create something cheap, convenient, and easy to set up. Traditional fermentation monitoring equipment is very expensive. The typical open-source alternative will set you back 80 euros (roughly $101), using the Arduino-sensor with a Raspberry Pi gateway via the BrewPi webserver. [Martin] did not want to go through the hassle of viewing BrewPi remotely, since it requires a home network and all of the configuration that would entail. Instead, he coupled an Arduino clone with a DS18B20 temperature sensor while using an ESP8266 module for wireless communication, all for less than 18 euros ($23). This connects to a simple webpage based on Scotch.io with a PHP backend (Laravel with RESTful API), a MySQL database, and an AngularJS frontend to display the graph. Once the sensor is placed into the fermenter bucket’s thermowell, the temperature is transmitted once a minute to the REST API. You can see the temperature over time (in Celsius). The design files are available on GitHub.

[Martin] would like to expand the functionality of BrewMonitor, such as adding the ability to adjust the temperature remotely by controlling a heater or fridge, and lowering its cost by single boarding it. Since the information is stored on the cloud, upgrading the system is much easier than using a separate gateway device. He doesn’t rule out crowdfunding campaigns for the future. We would like to see this developed further, since different yeast species and beer styles require very stringent conditions, especially during the weeks-long fermentation process; a 5-degree Celsius difference can ruin an entire brew! Cloud-based temperature adjustment seems like the next big goal for BrewMonitor. DIY brewers salute you, [Martin]!

[via Dangerous Prototypes]

Home Automation With A Custom Wireless Sensor Network

October 11, 2014 by Rick Osgood 5 Comments

We’re no strangers to home automation projects around here, but it’s not often that you see one described in this much detail. [Paul] designed a custom home automation system with four teammates for an undergraduate thesis project.

The system is broken into two main components; the server and the peripherals. The team designed their peripherals from early prototypes of an upcoming ArduIMU v4 measurement unit. They removed all of the default sensors to keep costs down and reduce assembly time. The units can them be hooked up to various peripherals such as temperature sensors, mains relays, RGB color strips, etc.

The central management of the system is performed using a web-based user interface. The web server runs on Java, and interacts with the peripherals wirelessly. Basic messages can be sent back and forth to either read the state of the peripherals or to change the state. As far as the user is concerned, these messages appear as simple triggers and actions. This makes it very simple to program the peripherals using if, then, else logic.

The main project page is a very brief summary of what appears to be a very well documented project. The team has made available their 182 page final report (pdf), which goes into the nitty-gritty details of the project. Also, be sure to watch the demonstration video below. Continue reading “Home Automation With A Custom Wireless Sensor Network” →

MacGyvered Optoisolator Is A Great Introduction

October 10, 2014 by Rick Osgood 17 Comments

Sometimes the best way to learn about a technology is to just build something yourself. That’s what [Dan] did with his DIY optoisolator. The purpose of an optoisolator is to allow two electrical systems to communicate with each other without being electrically connected. Many times this is done to prevent noise from one circuit from bleeding over into another.

[Dan] built his incredibly simple optoisolator using just a toilet paper tube, some aluminum foil, an LED, and a photo cell. The electrical components are mounted inside of the tube and the ends of the tube are sealed with foil. That’s all there is to it. To test the circuit, he configured an Arduino to send PWM signals to the LED inside the tube at various pulse widths. He then measured the resistance on the other side and graphed the resulting data. The result is a curve that shows the LED affects the sensor pretty drastically at first, but then gets less and less effective as the frequency of the signal increases.

[Dan] then had some more fun with his project by testing it on a simple temperature controller circuit. An Arduino reads a temperature sensor and if the temperature rises above a certain value, it turns on a fan to cool the sensor off again. [Dan] first graphed the sensor data with no fan hooked up. He only used ambient air to cool things down. The resulting graph is a pretty smooth curve. Next he hooked the fan up and tried again. This time the graph went all kinds of crazy. Every time the fan turned on, it created a bunch of electrical noise that prevented the Arduino from getting an accurate analog reading of the temperature sensor.

The third test was to remove the motor circuit and move it to its own bread board. The only thing connecting the Arduino circuit to the fan was a wire for the PWM signal and also a common ground. This smoothed out the graph but it was still a bit… lumpy. The final test was to isolate the fan circuit from the temperature sensor and see if it helped the situation. [Dan] hooked up his optoisolator and tried again. This time the graph was nice and smooth, just like the original graph.

While this technology is certainly not new or exciting, it’s always great to see someone learning by doing. What’s more is [Dan] has made all of his schematics and code readily available so others can try the same experiment and learn it for themselves.

Brushless Motor Controller Shield For Arduino

October 8, 2014 by Ethan Zonca 19 Comments

Brushless motors are ubiquitous in RC applications and robotics, but are usually driven with low-cost motor controllers that have to be controlled with RC-style PWM signals and don’t allow for much customization. While there are a couple of open-source brushless drivers already available, [neuromancer2701] created his own brushless motor controller on an Arduino shield.

[neuromancer2701]’s shield is a sensorless design, which means it uses the back-EMF of the motor for feedback rather than hall effect sensors mounted on the motor. It may seem strange to leave those sensors unused but this allows for less expensive sensorless motors to work with the system. It also uses discrete FETs instead of integrated driver ICs, similar to other designs we have covered. Although he is still working on the back-EMF sensing in his firmware, the shield successfully drives a motor in open-loop mode.

The motor controller is commanded over the Arduino’s serial interface, and will support a serial interface to ROS (Robot Operating System) in the future. This shield could be a good alternative to hobby RC controllers for robots that need a customizable open-source motor controller. The PCB design and source code are available on GitHub.

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