Internet is full of intetesting IoT projects built using Arduino, Raspberry Pi, ESP8266, ESP32, and many other hardware platforms. I will collect links to intetesting IoT projects to comments.
Feel free to post your best IoT project links to comments…
686 Comments
Tomi Engdahl says:
Simple Ethereum Vending Machines with NodeMCU
https://hackaday.com/2018/05/10/simple-ethereum-vending-machines-with-nodemcu/
Recently, we covered how to use the Etherscan API to query data (a wallet balance) from the Ethereum blockchain with NodeMCU. It’s a very useful method for retrieving information from a blockchain on embedded systems where storage and memory are an issue.
It has some limitations though. Most notably, it’s polling the API at some interval to retrieve information whether it has changed or not.
Simply send to an address via some method, and receive goods!
It turns out we can do exactly that with NodeMCU using WebSocket. Like HTTP, WebSocket is a communications protocol that uses TCP connections (typically over port 80), but it allows full-duplex communication. In other words, you can establish a connection to a server, and send/receive messages without needing to poll the server.
Accessing Blockchain on ESP8266 Using the NodeMCU Board
https://hackaday.com/2018/05/02/using-blockchain-explorer-apis-on-nodemcu/
Blockchains claim to be public, distributed, effectively immutable ledgers. Unfortunately, they also tend to get a little bit huge – presently the Bitcoin blockchain is 194GB and Ethereum weighs in at 444GB. That poses quite an inconvenience for me, as I was looking at making some fun ‘Ethereum blockchain aware’ gadgets and that’s several orders of magnitude too much data to deal with on a microcontroller, not to mention the bandwidth cost if using 3G.
Tomi Engdahl says:
Compact, $25 spectrometer
https://hackaday.io/project/143014-compact-25-spectrometer
AMS’s new AS7265X 3-chip set promises a compact, 18-channel, 20 nm FWMH spectrometer for less than $25
AMS makes several interesting sensors including the CCS811 air quality sensor which I use in my STM32 Sensor Tile project and the AS7262 6-channel light sensor, which appears now in a breakout board that Adafruit has just announced. The AS7262 offers six channels in the visible (430 to 670 nm) with 40 nm FWHM resolution. There is also another similar AMS sensor the AS7263 which offers six channels in the near IR (600 – 870 nm) with 20 nm FWHM resolution.
Tomi Engdahl says:
Simple Water Quality Analysis © GPL3+
An easy-to-build and low-cost water quality monitor.
https://create.arduino.cc/projecthub/momososo/simple-water-quality-analysis-30da58?ref=platform&ref_id=424_recent___&offset=5
try to use arduino analog input measure TDS ( Total dissolved solids )
and print it for analyze
Tomi Engdahl says:
Autonomous Fire Hazard System
https://www.hackster.io/Scythe/autonomous-fire-hazard-system-4aaade
The time has come to automate our good old fire alarms and make them part of an interconnected world.
Tomi Engdahl says:
IoT Smart Wallet (with Firebeetle ESP32 and Arduino IDE)
https://www.hackster.io/igorF2/iot-smart-wallet-with-firebeetle-esp32-and-arduino-ide-4513f9
This wallet can connect the internet, read the value of your cryptocurrencies from a Google spreadsheet and even work as a pedometer!
Tomi Engdahl says:
Sonoff: Control from Any Web Application or Page
https://www.hackster.io/TechGuru/sonoff-control-from-any-web-application-or-page-d5f6cd
This project covers how to control Sonoff from any webpage. No mobile application needed to control the appliance. Let’s get started.
I have not changed original firmware that comes out of the box from the manufacturer.
Create or login into IFTTT.com account.
Create 2 applets.
1. Create Webhook(If condition). Give small Event name. Next in “Then” action select “EWelink” service. You will have to create a account if not done yet. Just provide mobile number and sign in. You might need to register if not done already to start with. Next select
In the text box above in middle of URL…need to enter Event name created i.e Applet event name. In our casse witch is placed in “index.html” file is “sonoff_off” and “sonoff_on”.
Tomi Engdahl says:
Arduino Train for Kids © Apache-2.0
https://create.arduino.cc/projecthub/Steve_Massikker/arduino-train-for-kids-1156ad
Redesign of a cheap set of a kid’s railway into an intelligent train with control from the Android device.
Tomi Engdahl says:
Intra-Oral Device Detects Opioid Overdose
https://hackaday.com/2018/05/13/intra-oral-device-detects-opioid-overdose/
As you may have heard, the U.S. is in the grips of an opioid epidemic. Overdose deaths from heroin, oxycontin, and fentanyl have quadrupled since 1999. The key to detecting opioid overdose before it’s too late is in monitoring respiration.
[Curt White] is developing an intra-oral device to prevent opioid overdose via early detection. It tracks a patient’s inhale/exhale rate and sends the data over Bluetooth to an open-source website.
https://hackaday.io/project/106917-intraoral-respiration-monitor-overdose-detector
Tomi Engdahl says:
Smart-Home Lightning Hacks
https://www.linuxjournal.com/content/smart-home-lightning-hacks
Home automation should make life simpler, not more complex!
Tomi Engdahl says:
MoAgriS: A Modular Agriculture System
https://hackaday.com/2018/05/14/moagris-a-modular-agriculture-system/
Hackaday.io user [Prof. Fartsparkle] aims to impress us again with MoAgriS, a stripped-down rig for bringing crops indoors and providing them with all they need.
This project is an evolution of their submission to last year’s Hackaday Prize, MoRaLiS — a modular lighting system on rails — integrating modules for light, water, airflow, fertilizer and their appropriate sensors. With an emphasis on low-cost, a trio of metal bars serve as the structure, power and data transmission medium with SAM D11 chips shepherding each plant.
https://hackaday.io/project/91757-moagris-modular-agriculture-system
Tomi Engdahl says:
Location Sharing with Google Home
https://hackaday.com/2018/05/16/location-sharing-with-google-home/
With Google’s near-monopoly on the internet, it can be difficult to get around in cyberspace without encountering at least some aspect of this monolithic, data-gathering giant. It usually takes a concerted effort, but it is technically possible to do. While [Mat] is still using some Google products, he has at least figured out a way to get Google Home to work with location data without actually sharing that data with Google, which is a step in the right direction.
[Mat]’s goal was to use Google’s location sharing features through Google Home, but without the creepiness factor of Google knowing everything about his life, and also without the hassle of having to use Google Maps. He’s using a few things to pull this off, including a NodeRED server running on a Raspberry Pi Zero, a free account from If This Then That (IFTTT), Tasker with AutoRemote plugin, and the Google Maps API key. With all of that put together, and some configuration of IFTTT he can ask his Google assistant (or Google Home) for location data, all without sharing that data with Google.
http://www.notenoughtech.com/home-automation/google-home/google-home-location-sharing/
Tomi Engdahl says:
Solar Powered Environmental Monitoring Kit
https://www.hackster.io/taifur/solar-powered-environmental-monitoring-kit-b1d03d
A solar-powered open source kit for monitoring air quality, sound level, humidity, and temperature.
Tomi Engdahl says:
PocketBeagle Alexa
https://www.hackster.io/beaglefriends-octavosystems/pocketbeagle-alexa-0425b6
PocketBeagle® can become your personal Amazon Alexa assistant. Follow these instructions and this tiny BeagleBone will do more than fetch!
Tomi Engdahl says:
Versatile Shop Power Keycard System
https://blog.hackster.io/versatile-shop-power-keycard-system-3c24547e9cda
Tomi Engdahl says:
Mobile Weather Station Being Powered by Solar Energy
https://www.hackster.io/kutluhan-aktar/mobile-weather-station-being-powered-by-solar-energy-b44820
Get the weather information through an Android app constantly and use the solar energy generating by the PV panel to charge devices.
Tomi Engdahl says:
ESP8266 Loader App Lets Users Debug and Upload Binary Files via Android Mobile Devices
https://blog.hackster.io/esp8266-loader-app-lets-users-debug-and-upload-binary-files-via-android-mobile-devices-c46b1f1e5ce7
You can now use Android smartphones and tablets to flash any ESP8266 board of your choice as well as gaining access to the serial console for debugging on the go using Bluino Electronics’ ESP8266 Loader app.
Tomi Engdahl says:
Alexa And Particle Modernize Coffee Machine By One Iota
https://hackaday.com/2018/05/21/alexa-and-particle-modernize-coffee-machine-by-one-iota/
When [Steve Parker]’s girlfriend got a tea kettle that takes voice commands, he suddenly saw his fancy bean-to-cup coffee machine as a technological dinosaur. It may make good coffee, but getting the DeLonghi going is inconvenient, because it runs a self-cleaning cycle each time it’s turned on or off.
Thus began [Steve]’s adventure in trying to turn the thing on with Alexa via Particle Photon. Because of the way the machine is designed, simply adding a relay wouldn’t do—the machine would just turn off and back on, only to start the self-clean again. Once inside, he found it’s controlled by a PIC18LF2520. Further research indicated that it is powered by an off-line switcher that combines a power MOSFET with a power supply controller. [Steve] figured out that the buttons are read via square wave and interpreted by a multiplexer.
https://stevep.xyz/2018/05/17/delonghi-magnifica-now-with-alexa/
Tomi Engdahl says:
Ditch The Tapes, Put An Android In Your Deck
https://hackaday.com/2018/05/21/ditch-the-tapes-put-an-android-in-your-deck/
While we here at Hackaday never question why an individual took on a particular project, it surely doesn’t stop our beloved readers from grabbing their pitchforks and demanding such answers in the comments. Perhaps no posts generate more of this sort of furore than the ones which feature old audio gear infused with modern hardware. In almost every case the answer is the same: the person liked the look and feel of vintage hardware, but didn’t want to be limited to antiquated media.
Tomi Engdahl says:
Auto-Away Assist for NEST Thermostat
https://www.hackster.io/pjdecarlo/auto-away-assist-for-nest-thermostat-8ad566
Let Nest know when you are in another room to assist Auto-Away using motion sensors, Particle.io, and Azure!
The problem is that the Nest does not always determine home / away properly.
The Nest is a Wi-Fi enabled device, so why not just tell it when you are home using motion sensing or something similar? Nest is aware of this issue and sells a motion sensor and an additive monitoring thermostat for controlling temperatures in rooms outside of the Nest controller location. These sensors are really expensive and they are only compatible with the Nest v3 thermostats
Solution
All we really need is a method of informing the Nest that we are home using some form of hardware based trigger (PIR motion / reed switch / something more sophisticated). One would think that If This Then That would support this feature with their Nest integration, but there is nothing specific to setting the Home / Away status of the Nest at this time. That’s not a deal-breaker, we can just roll our own.
we need only a few ingredients:
A valid Oauth Token to allow us to make API requests to update Home / Away status through Nest’s developer API
A device which can detect presence and send an event to trigger this API call. We will use a Particle Core / Photon and a PIR motion sensor along with an integration to forward messages to an Azure IoT Hub.
A Service to make the actual call to the Nest API. We will use a serverless Azure function to make the call to the Nest API which will be triggered when events arrive through the aforementioned Azure IoT Hub.
Tomi Engdahl says:
Announce Who Is Home Using Facial Recognition
https://www.hackster.io/97766/announce-who-is-home-using-facial-recognition-dcc389
Perform facial recognition on a doorbell camera and announce who is home over text-to-speech. All data capture and processing is local.
Tomi Engdahl says:
GlimpseCam Is a Video-Enabled Headband Concept
https://blog.hackster.io/glimpsecam-is-a-video-enabled-headband-concept-8b1801fe98a2
Technology, and specifically smartphones, have brought us so much in terms of being able to see and share the world; unfortunately, they also consume much of our attention that would otherwise be on what’s in front of us.
Tomi Engdahl says:
How to Send Data to Ubidots Using Raspberry Pi and NodeRED
https://www.hackster.io/kierankieran/how-to-send-data-to-ubidots-using-raspberry-pi-and-nodered-128b5c
Struggling to get data from your Raspberry Pi to your cloud account? Fear not for the solutions to your problems lie within.
Tomi Engdahl says:
Internet of Laundry — Let the ESP8266 Watch Your Dirty Drawers Get Clean
https://hackaday.com/2018/05/20/internet-of-laundry-let-the-esp8266-watch-your-dirty-drawers-get-clean/
When you think of world-changing devices, you usually don’t think of the washing machine. However, making laundry manageable changed not only how we dress but how much time people spent getting their clothes clean. So complaining about how laborious our laundry is today would make someone from the 1800s laugh. Still, we all hate the laundry and [Andrew Dupont], in particular, hates having to check on the machine to see if it is done. So he made Laundry Spy.
https://andrewdupont.net/2018/02/15/laundry-spy-part-1-the-hardware/
Tomi Engdahl says:
Ditch The Tapes, Put An Android In Your Deck
https://hackaday.com/2018/05/21/ditch-the-tapes-put-an-android-in-your-deck/
TapeLess Deck Project, created by [Artur Młynarz]. His creations combine vintage cassette decks with an Android phone small enough to fit behind the tape door. An Android application which mimics the look of a playing tape, complete with “hand written” track info, completes the illusion.
http://www.mp3tapelessdeck.pl/
Tomi Engdahl says:
Card Reader Lockout Keeps Unauthorized Tool Users at Bay
https://hackaday.com/2018/05/20/card-reader-lockout-keeps-unauthorized-tool-users-at-bay/
Card Reading Shop Power Switch
http://www.instructables.com/id/Card-Reading-Shop-Power-Switch/
Tomi Engdahl says:
Hello, Tello – Hacking Drones With Go
https://www.hackster.io/deadprogram/hello-tello-hacking-drones-with-go-5a6a50
This project shows how you can control the new DJI Tello drone flight commands and video using the Go programming language.
Tomi Engdahl says:
IoT Camera Mover for Less Than $35
https://www.hackster.io/gatoninja236/iot-camera-mover-for-less-than-35-7bb0f6
Build a machine that can move a camera perfectly using the power of a webpage and even the Google Assistant with Particle.
I started this journey by imagining what I wanted in a device that moved a camera. What if my hands were full? Then I would want to use my voice. What if I only had my phone next to me? Then make a local webpage. This led me to use the Particle Photon, as the Particle Cloud API is extremely versatile. They have a javascript SDK which allows for access of many different cloud functions. Additionally, IFTTT has a Particle service, allowing for me to use the Google Assistant service with it.
Tomi Engdahl says:
How to Build an Intelligent IoT Gateway in 7 Easy Steps
https://developers.redhat.com/blog/2016/11/02/how-to-build-an-intelligent-iot-gateway-in-a-few-easy-steps/?sc_cid=7016000000127ECAAY
talked about the the critical role of the IoT gateway in the enterprise Internet of Things (IoT) as it enables real time decision-making at the edge, secures downstream devices and optimizes network utilization. So how does one go about building this gateway? In this blog, you’ll learn how to build an intelligent IoT gateway in a few simple steps – you can find the code at GitHub.
Tomi Engdahl says:
Industrial IoT Gateway Based on Android Things
https://www.hackster.io/mhanuel/industrial-iot-gateway-based-on-android-things-c680d1
A smart industrial gateway for the IoT world based on Android Things.
Tomi Engdahl says:
Alexa to Walabot Mess-o-Meter: Are We a GO for Ice Cream!
https://www.hackster.io/VBB/alexa-to-walabot-mess-o-meter-are-we-a-go-for-ice-cream-603f35
Gamify “keep your room clean” by linking dessert and outsource inspection to Walabot and Alexa to judge if “ice cream is unlocked” tonight.
Tomi Engdahl says:
Heart Rate Monitor on ThingSpeak IoT Platform
https://www.hackster.io/tech-duino/heart-rate-monitor-on-thingspeak-iot-platform-4977a8
Heart beat monitoring system using Arduino that will detect the heart beat using the DFRobot’s heart rate sensor.
Tomi Engdahl says:
Wedding Photo Booth with Raspberry Pi
https://www.hackster.io/sabat54i/wedding-photo-booth-with-raspberry-pi-1cea3a
For a wedding or other event, you need a photo booth! You will find here how to do this awesome project which make all guests happy.
Tomi Engdahl says:
How to Use Automotive Gauges to Monitor Your Internet Speed with an ESP32
https://blog.hackster.io/how-to-use-automotive-gauges-to-monitor-your-internet-speed-with-an-esp32-e04cdaf7669d
You almost certainly care about your internet speed, especially if you often stream video or play games online. But, how often do you actually check the speeds that you’re utilizing? If you want to start monitoring your network usage in an easy and intuitive way, Niik has a very thorough tutorial that will show you how to turn automotive gauges into an internet speed gauge.
http://www.instructables.com/id/Internet-Speed-Gauge/
Tomi Engdahl says:
Raspberry Pi Image Recognition with Alexa Voice
https://www.hackster.io/ken-walker/raspberry-pi-image-recognition-with-alexa-voice-6b7a01
SeeTalker tells you what it sees with the help of a Raspberry Pi computer, Microsoft image recognition and Alexa
Tomi Engdahl says:
https://www.hackster.io/oscarsalguero/sentinel-8234b3
Tomi Engdahl says:
Building Automation with Open Source Components
https://www.hackster.io/stefaanv/building-automation-with-open-source-components-327b68
Home automation based on Wago PLC, OpenHAB, MySensors, MQTT, Node. js, Grafana, InfluxDB, RFXcom and more.
Tomi Engdahl says:
Combining a Series of Sensors for a Cheap Spectrometer to Identify Everything
https://blog.hackster.io/combining-a-series-of-sensors-for-a-cheap-spectrometer-to-identify-everything-d4ef1d0091cd
Need a reflectance spectrometer, but don’t want to pay a lot of money? You can either buy AMS’s AS7265X demo kit for about $100, or you can build your own like Kris Winer, for a much cheaper price tag of $25. Winer designed his own as part of this year’s Hackaday Prize
Tomi Engdahl says:
Remote LED Control via Wi-Fi Using Zerynth App
https://www.hackster.io/federico-guidi/remote-led-control-via-wi-fi-using-zerynth-app-4b9937
Quick demonstration of the Zerynth ecosystem. This demo lets you manage an RGB LED via Wi-Fi with your smartphone thanks to the Zerynth App.
Tomi Engdahl says:
Manage Multiple Raspberry Pi Using Mobile Phone
https://www.hackster.io/jithinsanal1610/manage-multiple-raspberry-pi-using-mobile-phone-48f7c8
Easily manage multiple Raspberry Pi and/or Linux machines together in one go. Install software, update, upgrade and run command easily.
Once in a while we will have to SSH to each of them to perform some common tasks such as update, upgrade etc. Some days ago, I stumbled upon an article, where this guy built a Portable Hacking Station using Raspberry Pi, where he used an adnroid App named Juice SSH to control a Kali Linux installed Raspberry Pi.
Juice SSH and Cluster Snippets
Juice SSH is an all in one terminal client for Android mobile phones which includes SSH, Local Shell, Mosh and Telnet support.
Then I went through the list of plugins and noticed something called Cluster Snippets. The plugin helps us to execute codes on multiple devices in one go. You can add the code snippet, select all the devices you want the snippet to run, Simply select the snippet you’d like to execute, the connections you’d like to execute it on, and then use tap the run button to execute it.
Tomi Engdahl says:
$6 Weather Station Goes Where you Do
https://hackaday.com/2018/06/03/6-weather-station-goes-where-you-do/
We admit, we see a lot of weather stations. What makes [Mike Diamond’s] take on this old favorite interesting is that it is tiny enough to carry with you, and uses your cell phone as a hotspot to deliver its data. Of course, that assumes you have a phone that can act as a hotspot.
The parts are straightforward, a power supply, an ESP8266, and a weather sensor board. It looks as though you could easily slip the whole affair into a tube or maybe a 3D printed enclosure.
On the data end, the ESP8266 uses Cayenne to transmit data which is the same kind of IoT backend we see a lot lately. On the one hand, this allows you to distribute it without developing a phone application.
Make a $6 Tiny Portable Weather Station that Transmits Live Data Wherever You Are
http://www.whatimade.today/make-a-6-tiny-portable-weather-station-that-transmits-live-data-wherever-you-are/
Ask your iPhone for weather conditions and it’ll display data from a sensor somewhere nearby – often at the local airport – which might be miles away from your current location.
And at home, you may have IoT sensors that tell you the temperature in your bedroom or kitchen.
But what if you want to know the temperature, humidity, air pressure and humidity WHERE YOU’RE STANDING RIGHT NOW? Even your mighty cellphone can’t tell you all that.
You’ll only need three parts. All the links below are to Aliexpress.
BME280 – about $2.5
ESP8266_01 = about $2
AMS1117 3.3V MODULE – about $1
Tomi Engdahl says:
Planter Coughs for Poor Air Quality
https://blog.hackster.io/planter-coughs-for-poor-air-quality-5ecefcfb75ab
Whether outdoors or in nature, viewing live plants make us think of clean air
To imbue a houseplant with the ability to show off this stat, hacker “msbirfday” designed a planter that not only holds a plant on top, but hides electronics — including a Raspberry Pi Zero W and an SGP30 air-quality sensor to take readings.
Tomi Engdahl says:
Sigfox-Connected Basketball Hoop
https://www.hackster.io/sylvain-demortier/sigfox-connected-basketball-hoop-47091c
Challenge your friends with a connected hoop! This project counts your score using Arduino, Sigfox, and the IoT platform Losant.
Tomi Engdahl says:
Sigfox kWh Meter © GPL3+
https://create.arduino.cc/projecthub/jassak/sigfox-kwh-meter-d53f2c?ref=user&ref_id=288929&offset=0
What if our old electric energy power meter with rotary disk could be connected to the internet?
will connect your old inductive power meter to the internet. And what kind of meter exactly is it? It is the kind of oldest, but still used power meter. It has the rotary disk, which has reflective paint all the way round it with a little black stripe. Each time you see that black part passing by, it means one rotation has been completed. In this project 120 turns are equal to consumption of 1 kWh.
Tomi Engdahl says:
ParticleSwitch
https://www.hackster.io/shapy/particleswitch-cefd73
A Particle-Android powered wall socket for when your device is left charging at home and you want to switch it off or on from anywhere.
Tomi Engdahl says:
Movement Sensor Portable Device Connected with LoRa to TTN
https://www.hackster.io/McOrts/movement-sensor-portable-device-connected-with-lora-to-ttn-79d762
It is a portable device that sends a signal every time it moves. It uses the free LoRaWAN network that through TTN allows internet access.
Tomi Engdahl says:
DIY Wi-Fi Smart Scale (with ESP8266, Adafruit.io, and IFTTT)
https://www.hackster.io/igorF2/diy-wi-fi-smart-scale-with-esp8266-adafruit-io-and-ifttt-fc68d1
In this project I designed a smart bathroom scale, using 3D printing, an ESP8266, Arduino IDE, Adafruit.IO and IFTTT app.
Tomi Engdahl says:
Arduino – Web Pattern Unlock
https://www.hackster.io/phpoc_man/arduino-web-pattern-unlock-7e1f07
It’s a security feature for Arduino. User is required to input the unlock pattern before remotely controlling/monitoring Arduino.
Tomi Engdahl says:
Raspberry Pi Image Recognition with Alexa Voice
https://www.hackster.io/ken-walker/raspberry-pi-image-recognition-with-alexa-voice-6b7a01
SeeTalker tells you what it sees with the help of a Raspberry Pi computer, Microsoft image recognition and Alexa.
Tomi Engdahl says:
How to Wirelessly Power and Access a 1-Wire Network (Part 1)
http://www.powerelectronics.com/alternative-energy/how-wirelessly-power-and-access-1-wire-network-part-1
By using a single node for 1-Wire communication, temperature sensing, authentication, and memory storage are possible with harvested power from an NFC link.
How to Wirelessly Power and Access a 1-Wire Network (Part 2)
http://www.mwrf.com/systems/how-wirelessly-power-and-access-1-wire-network-part-2?NL=MWRF-001&Issue=MWRF-001_20180604_MWRF-001_332&sfvc4enews=42&cl=article_1_b&utm_rid=CPG05000002750211&utm_campaign=17696&utm_medium=email&elq2=c655df843d774d61a5575900aac1c045
Here’s a simplified approach to analyzing a regulated voltage source that can power and maintain communication on a 1-Wire network—if timing meets 1-Wire protocol specifications.
Tomi Engdahl says:
Yes-No: An Arduino Driven Mailbox
https://www.eeweb.com/featured-projects/yes-no-an-arduino-driven-mailbox
An Arduino Driven Mailbox project is a specialized mailbox characterized by a highly technological operation with the use of an Arduino and a mobile phone application for a more convenient way of receiving mails.
This project uses a Light Dependent Resistor (LDR) and an Adafruit Neopixel led ring to detect the presence of a mail and to indicate this presence respectively. In addition, the Arduino processes the information and sends notification to a mobile phone through a Bluetooth device connecting the phone and the Arduino.
The mail can be stored by clicking YES or otherwise delivered to the shredding machine. I
Yes – No : an Arduino Driven Mailbox
http://www.instructables.com/id/Yes-No-an-Arduino-Driven-Mailbox/