Continuous Surface Bracelet

This bracelet consists of differentiated gyroids, i.e. infinitely connected triply periodic minimal surfaces.The 3D printed result is a rigid porous structure that separates space into two oppositely congruent labyrinths of passages. Create the Differentiated Gyroids 1 Create a regular gyroids ne…
By: DianaS150

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from Instructables: exploring – featured

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IoT Air Quality Sensor

MQ2 and MQ9 gas sensor both have four pins:

  • VCC
  • GND
  • DO (Digital Control)
  • AO (Analog Output)

The analog output of MQ2 and MQ9 is between 0V to 5V whereas the analog pin of nodemcu can only read between 0V to 3.3V. That means nodemcu cannot read the data if MQ2 or MQ9 sensor output is above 3.3V. The data read is not accurate. Therefore, voltage is needed step down.

In this project, voltage divider by two resistors is used. The voltage output is determined by the ratio of the value of two resistors. I use 180ohm as R1 and 330ohm as R2 so that Vout is 3.3V.

So, Vin is connected to AO pin of MQ gas sensors. Vout is connected to channels of the multiplexer.

Only three pins of each sensor are used:

  • Vcc to 5V supply
  • GND to nodemcu GND pin
  • Vout of voltage divider to CD4051BE channel 1 and channel 2(pin14 and 15)

Multiplexer connection:

  • Vdd (pin 16) to 5V supply
  • INH, Vee, Vss (pin 6, 7, 8) to nodemcu GND pin
  • common out/in (pin 3) to nodemcu A0 pin
  • A, B, C (pin 11, 10, 9) to nodemcu D0, D1, D2

A, B, C (pin11, 10, 9) are used to select channel for output.

A, B, C are digital input which means only read 0 and 1.

3-digit binary number is formed in the order of CBA.

As we use channel 1 and 2, denary number of 1 and 2 in 3-digit binary number are 001 and 010 respectively.

Therefore, when we want output of channel 1, D0 output 1, D1 and D2 output 0.

When we want output of channel 2, D0 output 0, D1 output 1 and D2 output 0.

from Instructables: exploring – featured

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Blynk+GSM Sim800+Arduino Uno+DHT11

Download Blynk App from Play Store link below…


Open the App

New Project > Give a name to Project > Choose Device Arduino Uno > Connection Type GSM > Create

Auth Token was sent to your email id registered

> Press OK

>Click on + sign > Add Gauge x2, History Graph, Notification, Email

> Click on Gauge 1st Give name Temperature INPUT as Virtual V1, range 0 to 100

> Click on Gauge 2nd give name Humidity INPUT as Virtual v2, range 0 to 100.

> Click on History graph in 1st column give name Temperature Input as virtual v1, 2nd column give name as humidity input as virtual v2.

>Install email & Notification

from Instructables: exploring – featured

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Entrance Master Remote (w/ Raspberry Pi)

A breadboard is a board that helps you connect electronic components together and to your micro-computer Raspberry Pi. A small breadboard can be enough for this project (the GIF above were taken from the DIY Jukebox project with a bigger one.

First, let’s install the buttons on your breadboard. Separate each button enough. And connect hook-up wire between one of the leg of the button and the minus (-) line. That will allow us to use only one jumper wire for ground connection.

See GIF above

Now connect a jumper wire next to the other leg of each button (it must be on the same line number). This will make the data connection between your Raspberry Pi and the button to transform the physical push on the digital interface.

See 2nd GIF above

Now it’s time to connect those wires to the GPIO pins of your Raspberry Pi. Connect the wire in the ground line to a ground pin. Then connect each button jumper wire to GPIO pins, following the map below. For instance we chose here to connect with GPIO17, GPIO27, GPIO22.

Basically you can connect to any green pin on this map.

The physical connection is now done, we now need to set up the Prota Pi to recognize each button being pressed. For this we will use GPIO app in the next step.


GPIO app is an app that allows you to create command names for physical elements connected to your Raspberry Pi, like those buttons. We will later connect these commands into automation workflows (step 7).

  • Go to App Libraries and download GPIO app
  • Open GPIO app
  • Click on GPIO 17 and set it to Interrupt // Pull up
  • Click on “Set”

Now when you press your button, it should display on your GPIO interface (as below) “Rising interrupt” and “Falling interrupt”.

This means your Prota Pi reads the action of pressing the button. Now you can do the same thing with GPIO27 and GPIO22. Make sure all dots are lighten up like below, meaning all pins are set up.

Test each button to see if you do have for each the message “rising interrupt” / “falling interrupt”, which confirms the connection is working fine.

from Instructables: exploring – featured

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Easy Free Piston Stirling Engine

Easy Free Piston Stirling Engine

Stirling engines are really cool machines, invented by Reverend Dr. Robert Stirling in 1816 to rival the steam engine, they are one of the most efficient engines ever conceived.  Building one is a very rewarding experience, but it has a certain level of difficulty. However, [Attila Blade]’s version of a free-piston type Stirling engine is simple enough to be built in a matter of minutes.

To build the engine you only need a test tube, steel wool, a latex glove, an O ring and some wire. The construction is straightforward as you can see in the video. The whole engine rocks on the wire frame which also makes it different to most other Stirling engines that you can watch on the net. The free piston is just one type of several possible configurations for a Stirling. The most common one, is the beta type, usually made with soda cans, but it is much more difficult to build than [Attila Blade]’s engine.

This is definitely a fun project that you may want to try, and is also a great way to learn  thermodynamics concepts. Even if you don’t build this particular version, there are many other possibilities using mainly household items, or you can also check the very interesting history behind the Stirling engine.


from Hack a Day

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Vitals Starving Yourself Two Days a Week Is Actually Not a Bad Diet | io9 10 Banned, Censored, and C

Vitals Starving Yourself Two Days a Week Is Actually Not a Bad Diet | io9 10 Banned, Censored, and Controversial Movies That Are Now Cult Classics | Kotaku Persona 5: The Kotaku Review | Jalopnik ‘Battle Cars’ Is The Newest And Best Trend In The Auto World |

from Gizmodo

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Putting Pi In Infrared Doohickies

Putting Pi In Infrared Doohickies

The Raspberry Pi Zero W is a tiny, cheap Linux computer with WiFi. It’s perfect for Internet of Things things such as controlling ceiling fans, window blinds, LED strips, and judgmental toasters. This leads to an obvious question: how do you attach your ceiling fan and LED strips to a Pi Zero? A lot of these things already have infrared remotes, so why not build an infrared hat for the Pi? That’s what [Leon] did, and it’s Open Hardware with documentation.

[Leon]’s Anavi Infrared Pi Hat does exactly what you think it should do. There’s an IR receiver, two IR LEDs, and UART pins for debugging. That’s all you need to control infrared doohickies over the Internet, and [Leon] wrapped it up in a nice neat package that’s the same size as a Raspberry Pi Zero. Add on some documentation and you have something we rarely see: a project meant to be used by other people.

This focus on allowing people to actually use what [Leon] created can lead to only one cynical conclusion: he’s probably selling these things somewhere. The cynic is never surprised. [Leon] has a crowdfunding campaign going, that’s over 400% funded with a month to go. That’s okay, though: all the design files are available so if you want to build your own without supporting people who build useful devices, have at it.

from Hack a Day

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