Posts | Comments

Planet Arduino

Archive for the ‘capacitive’ Category

When was the last time you poured water onto your radio to turn it on?

Designed collaboratively by [Tore Knudsen], [Simone Okholm Hansen] and [Victor Permild], Pour Reception seeks to challenge what constitutes an interface, and how elements of play can create a new experience for a relatively everyday object.

Lacking buttons or knobs of any kind, Pour Reception appears an inert acrylic box with two glasses resting on top. A detachable instruction card cues the need for water, and pouring some into the glasses wakes the radio.

Inside, two aluminium plates —  acting as capacitive touch sensors — are connected to an Arduino using the Tact library from NANDSudio. Wekinator — a machine learning tool — enabled [Knudsen] to program various actions to control the radio. Pouring water between the glasses changes stations, rotating and tweaking the glass’ positions adjusts audio quality, and placing a finger in the glass mutes it temporarily.

It’s a great concept for a more engaging piece of tech, if perhaps a little unnerving to be pouring water around household electronics. Best take preventative measures before applying this idea elsewhere.

Dic
23

Arduino Plays White Tiles On Your Mobile Touchscreen

Android, arduino, arduino hacks, capacitive, Don't tap the white tile, iOS, White Tiles Commenti disabilitati su Arduino Plays White Tiles On Your Mobile Touchscreen 

Like many mobile gamers, [Daniel] has found himself caught up by the addictive “White Tiles” game. Rather than play the game himself though,  [Daniel] decided to write his own automatic White Tiles player. While this hack has been pulled off before, it’s never been well documented. [Daniel] used knowledge he gleaned on Hackaday and Hackaday.io to achieve his hack.

The basic problem is sensing white vs black tiles and activating the iPad’s capacitive touch screen. On the sensing end, [Daniel] could have used phototransistors, but it turned out that simple CdS cells, or photoresistors, were fast enough in this application. Activating the screen proved to be a bit harder. [Daniel] initially tried copper tape tied to transistors, but found they wouldn’t reliably trigger the screen. He switched over to relays, and that worked perfectly. We’re guessing that changing the wire length causes enough of a capacitance change to cause the screen to detect a touch.

The final result is a huge success, as [Daniel’s] Arduino-based player tears through the classic game in only 3.9 seconds! Nice work [Daniel]!

Click past the break to see [Daniel’s] device at work, and to see a video of him explaining his creation.


Filed under: Arduino Hacks

[Connor] was working on a project for his college manufacturing class when he came up with the idea for this sleek desk lamp. As a college student, he’s not fond of having his papers glowing brightly in front of him at night. This lamp takes care of the problem by adjusting the color temperature based on the position of the sun. It also contains a capacities touch sensor to adjust the brightness without the need for buttons with moving parts.

The base is made from two sheets of aluminum and a bar of aluminum. These were cut and milled to the final shape. [Connor] found a nice DC barrel jack from Jameco that fits nicely with this design. The head of the lamp was made from another piece of aluminum bar stock. All of the aluminum pieces are held together with brass screws.

A slot was milled out of the bottom of the head-piece to make room for an LED strip and a piece of 1/8″ acrylic. This piece of acrylic acts as a light diffuser.  Another piece of acrylic was cut and added to the bottom of the base of the lamp. This makes for a nice glowing outline around the bottom that gives it an almost futuristic look.

The capacitive touch sensor is a pretty simple circuit. [Connor] used the Arduino capacitive touch sensor library to make his life a bit easier. The electronic circuit really only requires a single resistor between two Arduino pins. One of the pins is also attached to the aluminum body of the lamp. Now simply touching the lamp body allows [Connor] to adjust the brightness of the lamp.

[Connor] ended up using an Electric Imp to track the sun. The Imp uses the wunderground API to connect to the weather site and track the sun’s location. In the earlier parts of the day, the LED colors are cooler and have more blues. In the evening when the sun is setting or has already set, the lights turn more red and warm. This is easier on the eyes when you are hunched over your desk studying for your next exam. The end result is not only functional, but also looks like something you might find at that fancy gadget store in your local shopping mall.


Filed under: Arduino Hacks
Nov
06

Capacitive Sensor Design

arduino, capacitive, Sensor Commenti disabilitati su Capacitive Sensor Design 

FMFOE1OI236UGEL.MEDIUM

by ohneschuh @ instructables.com:

Capacitive sensors are an elegant way to control an Arduino using the Capacitive Sensing Library. But the sensitivity and error tolerance depend strongly on the hardware (sensor) design. I found a design guideline here and tested different setups which mostly work well if the Arduino was powered by battery. But the sensor signal changes dramatically if I connect the Arduino to a power supply.

Actually I found a design for five (and more) sensors which works well powered with battery and power supply.

Capacitive Sensor Design - [Link]

Ott
28

The Nickelphone

arduino hacks, atmega644, capacitive, capacitive touch, coins, Midi, musical hacks Commenti disabilitati su The Nickelphone 

nickelphone

[Tyler Bletsch] sent us a tip about his new build: a keyboard that redefines “coin-operated.” The Nickelphone can emit square wave tones via a piezo buzzer, but [Tyler] made this 25-key piano as a MIDI keyboard capable of driving a full synthesizer.

He chose an ATMega644 as the brain because it’s Arduino-friendly but has more data pins—32—than the usual ATMega328 chip, which allows him to provide each key with its own pin. Each coin was soldered to its own wire and connects up to a 1MΩ resistor array. Coin-presses are recognized by the simple capacitive sensing technique outlined here, but [Tyler] needed to take advantage of a workaround to accurately detect multiple presses.

Check out [Tyler's] detailed project guide for more information as well as the source code. Check out the video of the Nickelphone after the break, then browse through some other capacitive touch hacks, like the Capacitive Touch Business Card or the Capacitive Touch Game Controller.


Filed under: Arduino Hacks, musical hacks

In this article we examine the mbed rapid prototyping platform with the Freescale FRDM-KL25Z ARM® Cortex™-M0+ development board.

Introduction

A while ago we looked at the mbed rapid prototyping environment for microcontrollers with the cloud-based IDE and the NXP LPC1768 development board, and to be honest we left it at that as I wasn’t a fan of cloud-based IDEs. Nevertheless, over the last two or so years the mbed platform has grown and developed well – however without too much news on the hardware side of things. Which was a pity as the matching development boards usually retailed for around $50 … and most likely half the reason why mbed didn’t become as popular as other rapid development platforms.

Also – a few months ago – we received the new Freescale Freedom FRDM-KL25Z development board from element14. I started to write about using the board but frankly it did my head in, as at the time the IDE was almost a one gigabyte download and the learning curve too steep for the time I had available. Which was a pity as the board is inexpensive and quite powerful. So the board went into the “miscellaneous dev kit” box graveyard. Until now. Why?

You can now use the Freedom board with mbed. 

It isn’t perfect – yet – but it’s a move in the right direction for both mbed and Freescale. It allows educators and interested persons access to a very user-friendly IDE and dirt-cheap development boards.

What is mbed anyway?

mbed is a completely online development environment. That is, in a manner very similar to cloud computing services such as Google Docs or Zoho Office. However there are some pros and cons of this method. The pros include not having to install any software on the PC – as long as you have a web browser and a USB port you should be fine; any new libraries or IDE updates are handled on the server leaving you to not worry about staying up to date; and the online environment can monitor and update your MCU firmware if necessary. However the cons are that you cannot work with your code off-line, and there may be some possible privacy issues. Here’s an example of the environment (click to enlarge):

As you can see the IDE is quite straight-forward. All your projects can be found on the left column, the editor in the main window and compiler and other messages in the bottom window. There’s also an online support forum, an official mbed library and user-submitted library database, help files and so on – so there’s plenty of support. Code is written in C/C++ style and doesn’t present any major hurdles. When it comes time to run the code, the online compiler creates a downloadable binary file which is copied over to the hardware via USB.

And what’s a Freedom board?

It’s a very inexpensive development board based on the Freescale ARM® Cortex™-M0+ MKL25Z128VLK4 microcontroller. How inexpensive? In Australia it’s $9 plus GST and delivery.

Features include  (from the product website):

  • MKL25Z128VLK4 MCU – 48 MHz, 128 KB flash, 16 KB SRAM, USB OTG (FS), 80LQFP
  • Capacitive touch “slider,” MMA8451Q accelerometer, tri-color LED
  • Easy access to MCU I/O
  • Sophisticated OpenSDA debug interface
  • Mass storage device flash programming interface (default) – no tool installation required to evaluate demo apps
  • P&E Multilink interface provides run-control debugging and compatibility with IDE tools
  • Open-source data logging application provides an example for customer, partner and enthusiast development on the OpenSDA circuit

And here it is:

In a lot of literature about the board it’s mentioned as being “Arduino compatible”. This is due to the layout of the GPIO pins – so if you have a 3.3 V-compatible Arduino shield you may be able to use it – but note that the I/O pins can only sink or source 3 mA (from what I can tell) – so be careful with the GPIO . However on a positive side the board has the accelerometer and an RGB LED which are handy for various uses. Note that the board ships without any stacking header sockets, but element14 have a starter pack with those and a USB cable for $16.38++.

Getting started

Now we”ll run through the process of getting a Freedom board working with mbed and creating a first program. You’ll need a computer (any OS) with USB, an Internet connection and a web browser, a USB cable (mini-A to A) and a Freedom board. The procedure is simple:

  1. Download and install the USB drivers for Windows or Linux from here.
  2. Visit mbed.org and create a user account. Check your email for the confirmation link and follow the instructions within.
  3. Plug in your Freedom board – using the USB socket labelled “OpenSDA”. It will appear as a disk called “bootloader”
  4. Download this file and copy it onto the “bootloader” drive
  5. Unplug the Freedom board, wait a moment – then plug it back in. It should now appear as a disk called “MBED”, for example (click to enlarge):

There will be a file called ‘mbed’ on the mbed drive – double-click this to open it in a web browser. This process activates the board on your mbed account – as shown below (click to enlarge):

Now you’re ready to write your code and upload it to the Freedom board. Click “Compiler” at the top-right to enter the IDE.

Creating and uploading code

Now to create a simple program to check all is well. When you entered the IDE in the previous step, it should have presented you with the “Guide to mbed Online Compiler”. Have a read, then click “New” at the top left. Give your program a name and click OK. You will then be presented with a basic “hello world” program that blinks the blue LED in the RGB module. Adjust the delays to your liking then click “Compile” in the toolbar.

If all is well, your web browser will present you with a .bin file that has been downloaded to the default download directory. (If not, see the error messages in the area below the editor pane). Now copy this .bin file to the mbed drive, then press the reset button (between the USB sockets) on the Freedom board. Your blue LED should now be blinking.

Moving forward

You can find some code examples that demonstrate the use of the accelerometer, RGB LED and touch sensor here. Here’s a quick video of the touch sensor in action:

So which pin is what on the Freedom board with respect to the mbed IDE? Review the following map:

All the pins in blue – such as PTxx can be referred to in your code. For example, to pulse PTA13 on and off every second, use:

#include "mbed.h"
DigitalOut pulsepin(PTA13);
int main() {
 while(1) {
 pulsepin = 1;
 wait(1);
 pulsepin = 0;
 wait(1);
 }
}

The pin reference is inserted in the DigitalOut assignment and thus “pulsepin” refers to PTA13. If you don’t have the map handy, just turn the board over for a quick-reference (click to enlarge):

Just add “PT” to the pin number. Note that the LEDs are connected to existing GPIO pins: green – PTB19, red – PTB18 and blue – PTB.

Where to from here? 

It’s up to you. Review the Freedom board manual (from here) and the documentation on the mbed website, create new things and possibly share them with others via the mbed environment. For more technical details review the MCU data sheet.

Conclusion

The Freedom board offers a very low cost way to get into microcontrollers and programming. You don’t have to worry about IDE or firmware revisions, installing software on locked-down computers, or losing files. You could teach a classroom full of children embedded programming for around $20 a head (a board and some basic components). Hopefully this short tutorial was of interest. We haven’t explored every minute detail – but you now have the basic understanding to move forward with your own explorations.

The Freescale Freedom FRDM-KL25Z development board used in this article was a promotional consideration supplied by element14.

Have fun and keep checking into tronixstuff.com. Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column, or join our Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

In this article we examine the mbed rapid prototyping platform with the Freescale FRDM-KL25Z ARM® Cortex™-M0+ development board.

Introduction

A while ago we looked at the mbed rapid prototyping environment for microcontrollers with the cloud-based IDE and the NXP LPC1768 development board, and to be honest we left it at that as I wasn’t a fan of cloud-based IDEs. Nevertheless, over the last two or so years the mbed platform has grown and developed well – however without too much news on the hardware side of things. Which was a pity as the matching development boards usually retailed for around $50 … and most likely half the reason why mbed didn’t become as popular as other rapid development platforms.

Also – a few months ago – we received the new Freescale Freedom FRDM-KL25Z development board from element14. I started to write about using the board but frankly it did my head in, as at the time the IDE was almost a one gigabyte download and the learning curve too steep for the time I had available. Which was a pity as the board is inexpensive and quite powerful. So the board went into the “miscellaneous dev kit” box graveyard. Until now. Why?

You can now use the Freedom board with mbed. 

It isn’t perfect – yet – but it’s a move in the right direction for both mbed and Freescale. It allows educators and interested persons access to a very user-friendly IDE and dirt-cheap development boards.

What is mbed anyway?

mbed is a completely online development environment. That is, in a manner very similar to cloud computing services such as Google Docs or Zoho Office. However there are some pros and cons of this method. The pros include not having to install any software on the PC – as long as you have a web browser and a USB port you should be fine; any new libraries or IDE updates are handled on the server leaving you to not worry about staying up to date; and the online environment can monitor and update your MCU firmware if necessary. However the cons are that you cannot work with your code off-line, and there may be some possible privacy issues. Here’s an example of the environment:

mbedcompiler

As you can see the IDE is quite straight-forward. All your projects can be found on the left column, the editor in the main window and compiler and other messages in the bottom window. There’s also an online support forum, an official mbed library and user-submitted library database, help files and so on – so there’s plenty of support. Code is written in C/C++ style and doesn’t present any major hurdles. When it comes time to run the code, the online compiler creates a downloadable binary file which is copied over to the hardware via USB.

And what’s a Freedom board?

It’s a very inexpensive development board based on the Freescale ARM® Cortex™-M0+ MKL25Z128VLK4 microcontroller. How inexpensive? In Australia it’s $9 plus GST and delivery.

Features include  (from the product website):

  • MKL25Z128VLK4 MCU – 48 MHz, 128 KB flash, 16 KB SRAM, USB OTG (FS), 80LQFP
  • Capacitive touch “slider,” MMA8451Q accelerometer, tri-color LED
  • Easy access to MCU I/O
  • Sophisticated OpenSDA debug interface
  • Mass storage device flash programming interface (default) – no tool installation required to evaluate demo apps
  • P&E Multilink interface provides run-control debugging and compatibility with IDE tools
  • Open-source data logging application provides an example for customer, partner and enthusiast development on the OpenSDA circuit

And here it is:

topside

In a lot of literature about the board it’s mentioned as being “Arduino compatible”. This is due to the layout of the GPIO pins – so if you have a 3.3 V-compatible Arduino shield you may be able to use it – but note that the I/O pins can only sink or source 3 mA (from what I can tell) – so be careful with the GPIO . However on a positive side the board has the accelerometer and an RGB LED which are handy for various uses. Note that the board ships without any stacking header sockets, but element14 have a starter pack with those and a USB cable for $16.38++.

Getting started

Now we”ll run through the process of getting a Freedom board working with mbed and creating a first program. You’ll need a computer (any OS) with USB, an Internet connection and a web browser, a USB cable (mini-A to A) and a Freedom board. The procedure is simple:

  1. Download and install the USB drivers for Windows or Linux from here.
  2. Visit mbed.org and create a user account. Check your email for the confirmation link and follow the instructions within.
  3. Plug in your Freedom board – using the USB socket labelled “OpenSDA”. It will appear as a disk called “bootloader”
  4. Download this file and copy it onto the “bootloader” drive
  5. Unplug the Freedom board, wait a moment – then plug it back in. It should now appear as a disk called “MBED”, for example :

mbeddrive

There will be a file called ‘mbed’ on the mbed drive – double-click this to open it in a web browser. This process activates the board on your mbed account – as shown below:

registered

Now you’re ready to write your code and upload it to the Freedom board. Click “Compiler” at the top-right to enter the IDE.

Creating and uploading code

Now to create a simple program to check all is well. When you entered the IDE in the previous step, it should have presented you with the “Guide to mbed Online Compiler”. Have a read, then click “New” at the top left. Give your program a name and click OK. You will then be presented with a basic “hello world” program that blinks the blue LED in the RGB module. Adjust the delays to your liking then click “Compile” in the toolbar.

If all is well, your web browser will present you with a .bin file that has been downloaded to the default download directory. (If not, see the error messages in the area below the editor pane). Now copy this .bin file to the mbed drive, then press the reset button (between the USB sockets) on the Freedom board. Your blue LED should now be blinking.

Moving forward

You can find some code examples that demonstrate the use of the accelerometer, RGB LED and touch sensor here. Here’s a quick video of the touch sensor in action:

So which pin is what on the Freedom board with respect to the mbed IDE? Review the following map:

frdm-kl25z-pinout-final1

All the pins in blue – such as PTxx can be referred to in your code. For example, to pulse PTA13 on and off every second, use:

#include "mbed.h"
DigitalOut pulsepin(PTA13);
int main() {
 while(1) {
 pulsepin = 1;
 wait(1);
 pulsepin = 0;
 wait(1);
 }
}

The pin reference is inserted in the DigitalOut assignment and thus “pulsepin” refers to PTA13. If you don’t have the map handy, just turn the board over for a quick-reference:

theback

Just add “PT” to the pin number. Note that the LEDs are connected to existing GPIO pins: green – PTB19, red – PTB18 and blue – PTB.

Where to from here? 

It’s up to you. Review the Freedom board manual (from here) and the documentation on the mbed website, create new things and possibly share them with others via the mbed environment. For more technical details review the MCU data sheet.

Conclusion

The Freedom board offers a very low cost way to get into microcontrollers and programming. You don’t have to worry about IDE or firmware revisions, installing software on locked-down computers, or losing files. You could teach a classroom full of children embedded programming for around $20 a head (a board and some basic components). Hopefully this short tutorial was of interest. We haven’t explored every minute detail – but you now have the basic understanding to move forward with your own explorations.

The Freescale Freedom FRDM-KL25Z development board used in this article was a promotional consideration supplied by element14.

Have fun and keep checking into tronixstuff.com. Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column, or join our Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

The post mbed and the Freescale FRDM-KL25Z development board appeared first on tronixstuff.

Feb
07

Fruit piano uses a different circuit than the Makey Makey

arduino, arduino hacks, banana, capacitive, fruit, Makey Makey, peripherals hacks, piano, touch sensor Commenti disabilitati su Fruit piano uses a different circuit than the Makey Makey 

screen

[Hasbi Sevinç] is using perishable goods in his electronics project. The orange, tomato, and two apples seen above act as keys for the virtual piano. The concept is the same as the Makey Makey which is often demonstrated as a banana piano. This implementation uses an Arduino to read the sensors and to connect to the computer running the piano program.

You can see there’s a fair amount of circuitry built on the breadboard. Each piece of fruit has its own channel to make it into a touch sensor. The signal produced when your finger contacts the food is amplified by transistors connected in a Darlington pair. That circuit drives the low side of a optoisolator transmitter. The receiving side of it is connected the I/O pin of the Arduino. You can see the schematic as well as a demo clip after the break.

This use of hardware frees up a lot of your microcontroller cycles. That’s because projects like this banana piano use the timers to measure RC decay. [Hasbi's] setup provides a digital signal that at most only needs to be debounced.

circuit


Filed under: arduino hacks, peripherals hacks
Feb
07

Fruit piano uses a different circuit than the Makey Makey

arduino, arduino hacks, banana, capacitive, fruit, Makey Makey, peripherals hacks, piano, touch sensor Commenti disabilitati su Fruit piano uses a different circuit than the Makey Makey 

screen

[Hasbi Sevinç] is using perishable goods in his electronics project. The orange, tomato, and two apples seen above act as keys for the virtual piano. The concept is the same as the Makey Makey which is often demonstrated as a banana piano. This implementation uses an Arduino to read the sensors and to connect to the computer running the piano program.

You can see there’s a fair amount of circuitry built on the breadboard. Each piece of fruit has its own channel to make it into a touch sensor. The signal produced when your finger contacts the food is amplified by transistors connected in a Darlington pair. That circuit drives the low side of a optoisolator transmitter. The receiving side of it is connected the I/O pin of the Arduino. You can see the schematic as well as a demo clip after the break.

This use of hardware frees up a lot of your microcontroller cycles. That’s because projects like this banana piano use the timers to measure RC decay. [Hasbi's] setup provides a digital signal that at most only needs to be debounced.

circuit


Filed under: arduino hacks, peripherals hacks
Gen
11

Control a Virtual World Using Music

ableton, arduino, capacitive, itp, max, max/msp, music, projection, unity3d Commenti disabilitati su Control a Virtual World Using Music 

productArboration controls a projected landscape based on the musical input of the user.

Read the full article on MAKE



  • Newsletter

    Sign up for the PlanetArduino Newsletter, which delivers the most popular articles via e-mail to your inbox every week. Just fill in the information below and submit.

  • Like Us on Facebook