Posts with «sensors» label

Logging refrigerator temperature with Arduino

What really happens when you open the refrigerator door? Sure, you know intuitively that cold air escapes, but just how much? And how fast does the food inside actually heat up? To find out, Ryan Bates came up with his own data logging setup using an Arduino Uno, a custom sensor shield, and a microSD card reader.

His device uses a photoresistor to tell when the door has been opened, as well as a DHT22 temperature/humidity sensor to log the air temperature and door status. Along with this, TMP36 sensors are placed around the fridge to get a more granular look at temperatures, including one attached to a pickle jar. 

The results seen in the video below are quite interesting, and more information on the build can be found here if you’d like to try something similar.

This thermochromic 7-segment display colorfully shows the temp and humidity

Instead of controlling his temperature and humidity display directly, maker Zaphunk did things a bit differently, driving the temperature of each segment with a Peltier element, or thermo-electric cooler (TEC), to change its color. 

Each segment is made out of a thermochromic material, cycling from a black off state to a greenish hue when on, for a device that can—somewhat ironically—show the temperature by changing its temperature.

Ambient conditions are read via a DHT22 sensor, and everything is controlled by a half-dozen Arduino Nanos. This number boards were needed in order to power the nine dual motor drivers that handle the Peltier elements, each of which require two PWM outputs, along with 5 IO pins. 

The display looks great in the video below and Arduino code is found on GitHub.

Arduino and industrial distance sensor communicate via RS-485

After obtaining an industrial distance sensor, TUENHIDIY decided to use it as the basis for an interesting visual indicator.

The device communicates with an Arduino Uno via an RS-485 module, and outputs distance values in the form of a 9 x 14 pixel display made out of discreet LEDs soldered onto an LoL Shield.

As shown in the video be low, it does a good job of sensing how far an object is from it on a table, and the 126 LEDs provide a nice brilliant display. 

Code for the build can be found on GitHub if you’d like to make something similar. Seeing as though the sensor used here will set you back close to $1,000, you may want to also consider alternatives like an HC-SR04 ultrasonic module instead! 

SENSEation Shows The Importance of Good Physical Design

Sensor network projects often focus primarily on electronic design elements, such as architecture and wireless transmission methods for sensors and gateways. Equally important, however, are physical and practical design elements such as installation, usability, and maintainability. The SENSEation project by [Mario Frei] is a sensor network intended for use indoors in a variety of buildings, and it showcases the deep importance of physical design elements in order to create hardware that is easy to install, easy to maintain, and effective. The project logs have an excellent overview of past versions and an analysis of what worked well, and where they fell short.

One example is the power supply for the sensor nodes. Past designs used wall adapters to provide constant and reliable power, but there are practical considerations around doing so. Not only do power adapters mean each sensor requires some amount of cable management, but one never really knows what one will find when installing a node somewhere in a building; a power outlet may not be nearby, or it may not have any unoccupied sockets. [Mario] found that installations could take up to 45 minutes per node as a result of these issues. The solution was to move to battery power for the sensor nodes. With careful power management, a node can operate for almost a year before needing a recharge, and removing any cable management or power adapter meant that installation time dropped to an average of only seven minutes.

That’s just one example of the practical issues discovered in the deployment of a sensor network in a real-world situation, and the positive impact of some thoughtful design changes in response. The GitHub repository for SENSEation has all the details needed to reproduce the modular design, so check it out.

TerraDome Gives Plants And Dinosaurs A New Home

Housing exotic plants or animals offer a great opportunity to get into the world of electronic automation. When temperature, light, and humidity ranges are crucial, sensors are your best friend. And if woodworking and other types of crafts are your thing on top, why not build it all from scratch. [MagicManu] did so with his Jurassic Park themed octagonal dome built from MDF and transparent polystyrene.

With the intention to house some exotic plants of his own, [MagicManu] equipped the dome with an Arduino powered control system that regulates the temperature and light, and displays the current sensor states on a LCD, including the humidity. For reasons of simplicity regarding wiring and isolation, the humidity itself is not automated for the time being. A fan salvaged from an old PC power supply provides proper ventilation, and in case the temperature inside the dome ever gets too high, a servo controlled set of doors that match the Jurassic Park theme, will automatically open up.

[MagicManu] documented the whole build process in a video, which you can watch after the break — in French only though. We’ve seen a similar DIY indoor gardening project earlier this year, and considering its simple yet practical application to learn about sensors, plus a growing interest in indoor gardening itself (pun fully intended), this certainly won’t be the last one.

Hackaday Prize Entry: Fochica Alerts You

It seems like no one should need to be reminded about the importance of not leaving children in cars, but it still happens. The Fochica project is a Hackaday Prize entry that equips the family minivan with car seat monitors—the name comes from FOrgotten CHild in Car Alert.

It’s an Open Source project consisting of a Bluetooth LE-equipped Arduino that monitors whether the seat is empty or occupied. Paired with a phone app, Fochica monitors pressure sensors and the seat belt’s reed switch to determine whether there’s a kid there. The user’s app checks whether he or she is within Bluetooth range of the car, while also checking whether the kid’s seat is occupied. When the first comes up false and the second true, an alert is sounded.

We could see this technology also being useful for home automation tasks–for instance, reminding you to close the garage door before you go to bed. It’s a great project, and also one of the finalists in the Best Product challenge of the Hackaday Prize this year.


Filed under: The Hackaday Prize

Hackaday Prize Entry: Fochica Alerts You

It seems like no one should need to be reminded about the importance of not leaving children in cars, but it still happens. The Fochica project is a Hackaday Prize entry that equips the family minivan with car seat monitors—the name comes from FOrgotten CHild in Car Alert.

It’s an Open Source project consisting of a Bluetooth LE-equipped Arduino that monitors whether the seat is empty or occupied. Paired with a phone app, Fochica monitors pressure sensors and the seat belt’s reed switch to determine whether there’s a kid there. The user’s app checks whether he or she is within Bluetooth range of the car, while also checking whether the kid’s seat is occupied. When the first comes up false and the second true, an alert is sounded.

We could see this technology also being useful for home automation tasks–for instance, reminding you to close the garage door before you go to bed. It’s a great project, and also one of the finalists in the Best Product challenge of the Hackaday Prize this year.


Filed under: The Hackaday Prize

Enjoy The Last Throes of Summer With a Nice Pool Automation Project

[Ken Rumer] bought a new house. It came with a troublingly complex pool system. It had solar heating. It had gas heating. Electricity was involved somehow. It had timers and gadgets. Sand could be fed into one end and clean water came out the other. There was even a spa thrown into the mix.

Needless to say, within the first few months of owning their very own chemical plant they ran into some near meltdowns. They managed to heat the pool with 250 dollars of gas in a day. They managed to drain the spa entirely into the pool, but thankfully never managed the reverse. [Ken] knew something had to change. It didn’t hurt that it seemed like a fun challenge.

The first step was to tear out as much of the old control system as could be spared. An old synchronous motor timer’s chlorine rusted guts were ripped out. The solar controler was next to be sent to its final resting place. The manual valves were all replaced with fancy new ones.

Rather than risk his fallible human state draining the pool into the downstairs toilet, he’d add a robot’s cold logical gatekeeping in order to protect house and home. It was a simple matter of involving the usual suspects. Raspberry Pi and Arduino Man collaborated on the controls. Import relay boards danced to their commands. A small suite of sensors lent their aid.

Now as the soon-to-be autumn sun sets, the pool begins to cool and the spa begins to heat automatically. The children are put to bed, tired from a fun day at the pool, and [Ken] gets to lounge in his spa; watching the distant twinkling of lights on his backyard industrial complex.


Filed under: home hacks, robots hacks

Machine learning for the maker community

At Arduino Day, I talked about a project I and my collaborators have been working on to bring machine learning to the maker community. Machine learning is a technique for teaching software to recognize patterns using data, e.g. for recognizing spam emails or recommending related products. Our ESP (Example-based Sensor Predictions) software recognizes patterns in real-time sensor data, like gestures made with an accelerometer or sounds recorded by a microphone. The machine learning algorithms that power this pattern recognition are specified in Arduino-like code, while the recording and tuning of example sensor data is done in an interactive graphical interface. We’re working on building up a library of code examples for different applications so that Arduino users can easily apply machine learning to a broad range of problems.

The project is a part of my research at the University of California, Berkeley and is being done in collaboration with Ben Zhang, Audrey Leung, and my advisor Björn Hartmann. We’re building on the Gesture Recognition Toolkit (GRT) and openFrameworks. The software is still rough (and Mac only for now) but we’d welcome your feedback. Installations instructions are on our GitHub project page. Please report issues on GitHub.

Our project is part of a broader wave of projects aimed at helping electronics hobbyists make more sophisticated use of sensors in their interactive projects. Also building on the GRT is ml-lib, a machine learning toolkit for Max and Pure Data. Another project in a similar vein is the Wekinator, which is featured in a free online course on machine learning for musicians and artists. Rebecca Fiebrink, the creator of Wekinator, recently participated in a panel on machine learning in the arts and taught a workshop (with Phoenix Perry) at Resonate ’16. For non-real time applications, many people use scikit-learn, a set of Python tools. There’s also a wide range of related research from the academic community, which we survey on our project wiki.

For a high-level overview, check out this visual introduction to machine learning. For a thorough introduction, there are courses on machine learning from coursera and from udacity, among others. If you’re interested in a more arts- and design-focused approach, check out alt-AI, happening in NYC next month.

If you’d like to start experimenting with machine learning and sensors, an excellent place to get started is the built-in accelerometer and gyroscope on the Arduino or Genuino 101. With our ESP system, you can use these sensors to detect gestures and incorporate them into your interactive projects!

Monitor your Bonsai with the help of Arduino Uno

Bonsai trees are not like other plants. There’s no single watering schedule that can be applied to a bonsai and the best way to tell if the bonsai needs water is to touch the soil. Experienced growers know when a tree needs to be watered by observing the foliage or just by the weight of the pot. If you are not used to taking care of this type of tree, Bonsai Watchdog could be the perfect project for you. It runs on Arduino and Genuino Uno and makes it really easy to monitor the moisture level in the soil.

Thomas Baum, created it and shared it some days ago on the Arduino Community on G+ :

Two pencil leads, an Arduino and a 12864 (ST7565) LCD watches out my little bonsai. The filling level shows how often the sapling need to be watered.
source and discription (in german) you can find here:
http://tiny.systems/categorie/lcdProjekt/BonsaiWatchdog.html