IoT Based Notification System Using Android App

Presented here is a smart notification system for a door sensor, motion detector, fire alarm and doorbell using Raspberry Pi (RPi) and Pushover app. The project triggers an event through various sensors and sends notifications to your smartphone. Sensors used in this project include a magnetic reed switch for a door or window, PIR sensor for motion detection and NTC thermistor for fire alarm.

The issue of security is becoming more prevalent. The Internet of Things (IoT)-enabled home security solutions like this use sensors to collect and share data from multiple edge devices. If an attacker gains access to these smart systems through malicious means, the underlying functional logic of control systems can alert the owner. Connected home security systems offer a myriad of features including door and window sensors, motion detectors, fire alarms and so on, all connected via the Cloud to a mobile device or the Web.

Block diagram of the smart alert notification system using Android app is shown in Fig. 1.

Pushover app

Pushover is a service on the Web and an app for your phone or tablet that acts as a gateway for notifications. It can alert you to anything, including job postings, status of rain, emails from important people or a sensor activated in your home. Pushover lets you set up as many noise-free time periods as you like, using a feature called Quiet Hours. You can access alarm indications from anywhere in the world.
Circuit and working

Circuit diagram of the smart notification system using RPi is shown in Fig. 2. Hardware includes Raspberry Pi, Android phone, PIR sensor, reed switch, NTC thermistor, doorbell and a few other components.

Fig. 2: Circuit of the IoT based notification system using RPi

The PIR sensor connected across CON1 detects the presence of people through changes in infrared radiation from the human body in front of the door. It outputs around 3.3V high signal whenever it detects radiation change and correspondingly sends alert signals to your Android phone.

The magnetic reed switch connected across CON2 is usually installed on the frame of an exterior door or window. When the door or window opens, it moves away from the frame, magnetic field around the switch gets removed and corresponding alert signal is sent to your Android phone.

NTC thermistor connected across CON3 is used as the temperature-cum-fire sensor. Resistance of the NTC thermistor decreases with increase in temperature.

At room temperature, transistor T2 conducts. When temperature of the sensor goes above 70°C [depending on thermistor constant (K)], T2 stops conducting. When T2 stops conducting, an alert signal is generated in RPi, which is sent as a push message to the Android phone.

Most doorbells produce pulse-wave modulation waves while ringing. You need to hack the doorbell so that it produces at least 2V (pulse-wave modulation with low-pass filter) output signal. You may use this signal as an interrupt signal to drive RPi pin and generate an alarm log in your Android phone. Door-bell signal is fed to RPi through CON4.

When someone rings the doorbell, you will get a notification on your phone. Various alert notifications received on Android smartphone are shown in Fig. 3.

Software

Pushover makes it easy to get real-time notifications on your smartphone. Follow the steps given below to activate Pushover app on your Android device.

1. On your mobile device, open Pushover app and log into your account. You will be asked to register your device by providing a name for it.
 2. Visit https://pushover.net on your computer and log into your account. You should see your devices listed in a section called Your Devices, a little way down the page. Verify that the devices you have registered are on this list and are enabled.

3. Note down your user key (like, uyaa3u82r6rw853a2zhwj7afyxq4ba) as shown in Fig. 4. You will need it for your Python code.

Fig. 4: Typical user key generated on Pushover app

4. To get API key, click on Your Applications (doorbell) and note down your API token/key (like, au3kybdp4bmv3xs3qp1prku7pcrp9r) as shown in Fig. 5.

Fig. 5: Typical API key

5. Under Settings in Pushover, you can set an audio alert for quiet hours, etc for your mobile as per your requirement.

Testing Pushover app

Open Pushover app on your Android mobile. Open appliance.py file on the terminal in RPi. Change user_key and application_key in the code with your keys obtained as shown in Figs 3 and 4. Run the following command:

$ sudo python appliance.py

With the server connected to RPi, you will get ‘Appliance Server Started’ message in the terminal and ‘Appliance Started’ message on your mobile. As per the interrupt signal received from the input sensors (motion, door break, fire, doorbell, etc), the corresponding alert notification will be received on your Android phone through Pushover app.

Download Source code

Sourced By : EFY Author

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Now Low-Cost Arduino Thermal Camera

Do you still remember the H1N1 outbreak in Asia? The manifestations are usually flu-like symptoms which includes fever, cough and colds. The best way to detect fever when people are arriving from the affected areas was to use a thermal camera. These were widely used in Asian countries especially on airports but not all can afford one because it’s very expensive.

We can all agree that this is the greatest deal ever! A thermo-cam which costs around 100$, now there is no reason it can’t be bought by even poor countries to help prevent the spread of the disease. Credit must be given to inventions like this because it’s really a big help.

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Geiger Counter Uses Cockroft-Walton Multiplier

The recent tsunami in Japan and the on-going calamity with the Fukushima nuclear power plant has apparently greatly increased sales of radiation meters, not only in Japan but elsewhere around the world. This device will allow an estimation of the level of radioactivity, being sensitive enough for background radiation monitoring or to provide an estimation of the level of radioactivity from sample objects such as Thorium gas mantles in LPG lamps. The circuit is compatible with several Geiger Muller tubes and three types of indication are provided: the good old-fashioned audible click with each discharge, a flashing LED or an analog meter providing a rough average of radiation levels.

Geiger Counter Uses Cockroft-Walton Multiplier Circuit



A normal background count in New Zealand with the smaller GM LND712 tube is around 30 counts per minute, while the larger and more-sensitive LND7312 pancake tube will count about four times this figure. Both GM tubes will detect alpha, beta and gamma radiation. Unless the tube is “filtered”, there is no way of knowing just what type of radiation is being detected, although a rough guess can be made. Alpha particles will be stopped by placing a sheet of paper between the tube and the source, Beta particles (electrons) will be stopped with a few layers of aluminium foil and the more lively Gamma rays will need a layer of lead.

The circuit provides a regulated 500V supply for the Geiger Muller tube. This voltage places the tube into its linear operating mode so that a discharge inside the tube will occur when a particle enters through the mica window of the tube and causes the gas to ionise. The very short pulse produced is stretched and used to signal that a discharge has occurred. The power supply consists of an oscillator and small transistor driving the 6V secondary of a 240VAC mains transformer. The stepped up output of the transformer is fed to a Cockroft-Walton voltage multiplier consisting of diodes D3-D7 and the associated 47nF 630V metallised polyester capacitors.

IC1 is a 40106 Schmitt trigger inverter and IC1a is connected as an oscillator running at several hundred hertz. This is buffered by IC1b and fed to the base of NPN transistor Q1 which then drives the abovementioned transformer. IC1c acts as an error amplifier to regulate the high voltage fed to the GM tube. A portion of the DC voltage produced at the junction of diodes D4 & D5 is monitored by a voltage divider consisting of the 4.7MO and 47kO resistors, in combination with trimpot VR1. When the voltage from D5 is below the positive threshold of IC1c, its output will be high and IC1a will be able to oscillate. Hence, the oscillator will pulse on and off, to maintain the 500V set by VR1.

Each time there is a discharge in the GM tube, the resultant current triggers the BT149 SCR which discharges the associated 100nF capacitor and thereby acts as a pulse stretcher to drive the three remaining inverters in IC1. These in turn drive a high-brightness red LED (LED1), a piezo transducer and an analog metering circuit which is based on an old VU meter movement with a scale graduated in counts/minute. The current drain of the circuit is 10mA and a small 9V battery should run the counter for many hours. Warning: do not touch the window of the GM tube. These are very fragile and made of very thin mica, to allow the low-energy alpha particles to pass through. With the LND 712, 200 counts per minute is roughly equivalent to 0.3 micro-seiverts.

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NES Controller

The article will guide you on how to use NES controller in Atari 2600 or ZX Spectrum using an Arduino. Read through the entire article to have a better idea. An arduino and a few connectors are the only components involved here. Since the source code is small, any Arduino board can be utilized. The detailed list of components involved is mentioned below:

• Arduino
• DB-9 Male connectors – 2 nos
• DB-9 Female connector
• 5 Leds for the test dongle
• 5 resistors 330 Ohms 1/4 Watt for the test dongle
• Connecting wires

The DB-9 female plus wires can be replaced by a used Atari Joystick cable if required. The NES cable also can be cut and connected to the arduino. But the wires should be identified without any confusion. The source code is compiled and uploaded to the Ardunio. IDE version 0.22 was used to develop the code. In order to observe the exact behavior of the circuit, a dongle has to be used before the circuit is conneced to the ATARI. Buttons on the NES controller are used to activate the LEDs in the dongle.

The Arduino board has to be powered if a dongle is used for testing the circuit. The joystick controller provides the necessary power that is required for the Arduino to function. No external power is required in this case. This marks the end of the design and testing. The controller is now complete and ready for use.

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Remote Controlled Surveillance Robot

This post will provide you with the basic information on how a remote controlled vehicle can be constructed. Read on to know more about this.

The components required to construct the vehicle is listed below:

• 1.2Ghz 1000mW Receiver+Transmitter
• USPS Priority Mail boxes
• Hitec Optima 6 2.4Ghz Receiver
• Arrowind 18A Brushless Speed Controller
• 2200mAh 20C LiPo Battery Pack
• Brushless motor
• Custom motor-reversing relay board
• Foam wheels
• 7-Inch Handheld LCD TV
• Servo

The first thing to do here is to test the wireless transmitter. All the required components are mounted on the USPS mail box. Once the test is done, the box is strapped onto a nitro RC truck. The vibrations caused prevents the truck to be driven via the wireless video feed. The best thing to do in this case is to add wheels and propulsion to the box.

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Reuse Old Mobile Phone Battery for LED lighting

Normally mobile batteries have a lifespan of 2-5 years under normal usage. But then we have to replace them. Nowadays there are cheap replacement batteries which cost no more than 1$. But these low cost batteries run only 6-12 months. What to do with the used batteries, which can’t be reused in mobiles? Well, easy solution is to use the batteries in a circuit that requires less current. We can use them for LED lighting.

Do you have old unusable Mobile battery?

Normally mobile batteries have a lifespan of 2-5 years under normal usage. But then we have to replace them. Nowadays there are cheap replacement batteries which cost no more than 1$. But these low cost batteries run only 6-12 months. What to do with the used batteries, which can’t be reused in mobiles?

Well, easy solution is to use the batteries in a circuit that requires less current. We can use them for LED lighting. Thus your automatic lighting emergency light is ready which runs by your waste Mobile Battery. 

Source by : www.circuitsproject.com

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How to make an Apple II computer fit on your wrist (streampowers)

Disclaimer: streamPowers.blogspot.com is not responsible for any damage caused to your devices due to any information found on this site.  Please use this knowledge at your own risk.

About a year ago I came across an interesting article in Make Magazine about a guy who took his Fossil Wrist PDA and installed an Apple II emulator on it.  He was able to load many of the Apple II software titles and run them at regular speed.  The thought of having a fully functioning Apple computer on my wrist excited me enough to give it a try.   

People that are attempting to do this should be familiar with the Palm OS as well as using jot or Graffiti 2 as an input method.  The Fossil Wrist PDA (now discontinued) features a tiny gray 160×160 pixel screen, the same number of pixels as most palm devices up to Palm III, with 16 shades of gray. The watch runs Palm OS 4.1 with its 66MHz processor and has a tiny stylus hidden in the watch clasp. It is able to carry out most PDA functions, and run any normal Palm OS-compatible application (up to 4.1). It features 8 Mb of RAM (about 7.7 Mb available to user) and 4 Mb of flash memory. Like other Palm OS devices, it can synchronize or exchange information with PC or Mac, has, a virtual keyboard, and a touch screen with indiglo. The device also has a watch mode, with several “watch faces” to display the time.  These things were only out for a couple of years and were available in 2 different models.  You can usually find the first model on ebay going for about 50 bucks.  I was able to find a second gen one (FX2008) which is much more eye appealing for about $80 dollars brand new.  This isn’t a bad price considering they were $199 when they were first released. 

The first thing you will need to make this work (besides the watch) is an Apple II emulator called Appalm, which can be downloaded here.  Next you will need some Apple software disk images.  You can do a web search for “apple II roms” and should come across some sites which have software already in the *.dsk format.  Of course it is only legal to use these images if you own the original software disks.  The emulator requires you to convert the dsk files in to a file that the watch can actually read called pdb files.  The emulator’s zip file comes with an MS DOS executable to do this for you.  The emulator comes with easy to understand readme file, that will tell you how to set everything up.  One note before choosing which software to run, the watch display is incredibly small and sometimes text can be unreadable, unless you’re using a microscope.  Also the game controls are not optimal.  The emulator has a button mapping feature, but there are only 3 buttons and an up and down rocker switch that can be assigned a function.  If you want to load some games I recommend playing text based games like Zork or games that only require an up and down or a left and right movement like Galaxian or Zaxxon.  The watch lets you enter text by drawing in either jot or graffiti right on the screen and responds pretty well.  Installation of the emulator is pretty easy.  Just sync all the included palm files as well as some software on to the watch, and after the unit resets you should see the emulator icon.   

After the program boots you should see the Apple IIe boot screen.  Tap the tab at the top and select load disk image 1.   

 

Then choose the disk image you want to load, and check the box reset after load.  After 7 seconds or so your original apple program should now load, tap the tab at the top again to customize your other options, like input and emulation output (which I like to speed up).  I reassigned the right top and bottom buttons to be used as joystick one and two buttons (this is good for a game like Karateka).

 

  

 

 

 

So there you have it an Apple II wrist watch, definitely cooler then that old Casio calculator watch you use to sport.  You probably won’t want to play around for too long though, being your controls are really limited and you can get a headache from squinting at the screen for too long.  Battery life is also an issue but it is good for bringing back those old nostalgic memories of playing on an Apple II.  One side note, I also found a commodore 64 emulator that should work as well, just something else for you to try after your Apple project.

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Tweeter Used to Sense Vibrations

The creator built a neat looking project which uses a piezoelectric element from a tweeter to detect vibrations. He is using a Zilog eZ8 series microcontroller which seemed to be very popular years ago.

This project dependently using a strong vibration while the enclosure has been placed on the top of vibration sensor. The LED matrix has two eyes the wandering around effects. Whenever there is no vibration being detected the eyes will shut down as if they were sleeping.


A button was placed behind to manually switch it into various modes. It uses a four AA batteries and can draw 150uA when asleep while it draws for about 150mA when up.

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Streampowers PC Power Box with E-fuse

This little circuit can assist you to get rid of all surplus tiny ac mains adaptors from your desktop. The circuit is nothing, however a sensible dc power box directly powered by the smps of your desktop pc. Regulated, clean and guarded +12VDC is offered at the output of this unit. additionally, a USB power port is provided to re-charge transportable devices as well as cellphones and music players, etc.

How will the computer power box works

All you would like is to open your system box and connect an unused 4-pin drive power connector from the system smps to the current circuit. +12V (Yellow wire) from the smps is processed by a resettable electronic fuse designed around elements T1, T2 and T3 and feed to the output terminal. equally the +12V is down converted to stable +5V by fastened three pin regulator IC1.

Smart dc power box circuit schematic

As a result, +12V (500 -750mA max, based mostly on the electrical characteristics of T2 used) and +5V (1A max) DC provides are obtainable for external use, while not affecting the traditional computer functions. Switch S1 is that the power on/off cum reset switch. Resistor R3 sets the utmost allowable output current rate and T1 disables the output power switch T3, when output load current exceeds the set price.

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FTDI Bitbang IR Remote - Transmitter / Receiver

I use my computer every single minute, I do my work at home and I need to finish lots of paperwork. My computer helps me in almost everything I do. I make sure that my pc is able to do multitasking and functioning well. Just like our body, it should be fit to do all the workload that must be finished within the day.

To come up with another task that a pc can add to its functions, an IR remote was created through an FTDI that receives and transmits data other than the Universal Serial Bus. This is definitely a big help that my pc can easily cope up with simultaneously.

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Capacitor and Resistor in One Switch Box

It would be nice and comfortable doing our work and what we needed are readily available to save time and effort. It lessens the hassle of looking for missing pieces or even using multiple devices to check the accuracy and effectiveness of the equipments we are using.


Just like this switch box that has a capacitor and resistor in one unit. It will be easier and faster to check the capacitance and resistance by switching the knobs. This device may look old-fashioned but can really come very handy. This is simple and not that expensive to make and very useful in electronic projects or for the purpose of collecting devices for future use.

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