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Planet Arduino


Look closely at the colored pixels on this pair of 8×8 RGB LED modules and you’ll be able to pick out some of the familiar shapes of Tetris pieces. It’s impressive that [Jianan Li] built his own color Tetris including the theme music, but look at this breadboard! The layout of his circuit is as equally impressive as the code he wrote to get the game up and running. It takes a fair amount of planning to get a circuit of this complexity to fit in the space he used, right?

There are two microcontrollers at work, each running the Arduino bootloader. The main chip is an ATmega328 which is responsible for monitoring the buttons and controlling game play. The other is an ATmega85. The eight pin chip listens to it’s bigger brother, playing the theme song when the game starts, and pausing or resuming to match the user input So is the next stop for this project playing Tetris on the side of a building?

Don’t miss the demo video after the break. We’ve also rolled in a video of his Arduino-based piano. It’s built on a breadboard that’s nearly as impressive as this. But what delights us is his skill at playing Pokemon themes on the two-octave tactile switch keyboard. Obviously those piano lessons his parents shelled out for really paid off!

Filed under: Arduino Hacks

It runs on an Arduino

arduino, inspiration, meme, press Commenti disabilitati

It runs on Arduino


New Yorker‘s cartoon

Screen shot 2013-09-27 at 2.57.27 PMBritish artist Alex Allmont built this elegant one-motor Lego drum machine with a Arduino, a proto shield on top wired with a Lego Power Functions power connector, a Digital Delay pedal, and a Drumcomputer MFB-522.

Read more on MAKE

I'm lowering the top BTW

The engineering in the boat the cooling fan circulates air blowing it out between the motors. This wee fan moves lots of air on 7.4 Volts

Arduino Inputs from RX

Ch3   Throttle                       Arduino pin 4
Ch1   Steering                       Arduino pin 5
Ch5   Throttle limit                Arduino pin 6
Ch2   Steering on Throttle       Arduino pin 7

Arduino analogue inputs

Anin 0  Ambient temp sensor                      Anin 1  Hall effect current sensor

Arduino outputs

Pin 8    Left jet
Pin 9    Right jet
Pin 10  Cooling fan speed
Pin 11  Steering

Mixing of the outputs

  int SterringOnThrottle = (long)map((int)ch4v, 1500, 1100, 0, 1000); 
  if(SterringOnThrottle < 0) SterringOnThrottle = 0;
  SteeringBias = (long)map((int)ch3v - (int)ch3vWOZ, 0, 1000, 0, SterringOnThrottle); 
  int SteeringAngle = (long)map((int)ch3v, 1100, 1900, 1000, 2000);
  //Limit fan speed for 11.1 V
  FanSpeed = map(FanSpeed, 1100, 1900, 1000, 1500);
  //Update the outputs
  Servo1.writeMicroseconds((int)Throttle - (int)SteeringBias);
  Servo2.writeMicroseconds((int)Throttle + (int)SteeringBias);

The cooling system

The fan is a 27 mm EDF should keep the air moving with a 10A ESC

There is a big heatsink and fan on the 30 AMp ESC's


Getting Started with Yún


The Arduino Yún is an Arduino board unlike any other. While programming it is very similar to the Arduino Leonardo and uses the same processor, the Atmel ATmega32U4, it also has an additional processor, an Atheros AR9331, running Linux and the OpenWrt wireless stack. Programming the 32U4 via USB is identical to the Arduino Leonardo. Once you’ve configured the Yún to connect to your WiFi network, you can program the 32U4 via WiFi as well.

We prepared a video to explain how to take the first steps with the board, you can watch it below and then keep reading the Getting Started Guide:




Kiwi as Projects 2013-09-27 07:29:00

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Corner cases in the matrix page

1.    Adding static text
2.    Adding links to courses

The setup for above layout is as follows

The misc text fields are as follows

This is how we setup the matrix for these corner cases

Here is the markup and text we are using in the matrix

MiscText1 Some styled text

MiscText2 A link to the new elective description page

MiscText3 This is a styled piece of text List a being immediately below the matrix
One from list A

The data in the cells is assigned to the matrix cells as follows

LINC 101,LINC 102 A,PHSC 102,MGMT 103,PLSC 104,ANSC 105,SOSC 106,[es:MiscText2],

LINC 201,ANSC 213,PLSC 204,MGMT 201,SOSC 224,QMET 201,[es:MiscText2],[es:MiscText2],[es:MiscText2],

AGRI 393,[es:MiscText3],[es:MiscText3],[es:MiscText3],[es:MiscText3],[es:MiscText3],[es:MiscText2],[es:MiscText2],

Setting up a list in linking to the courses in EPiServer

In the editor

Editing a link

Here is the link address in the Address: filed shown above

This can all be done in EPiServer as with any other link


Normally, internet-controlled household devices are a cobbled together mashup of parts. This is great for a prototype, but if you’re looking for something that will last a decade in your garage, you’ll need something a little cleaner and more robust. [Phil]‘s Internet-enabled garage door opener is just that, replete with a custom-made enclosure for his Arduino powered system.

The main hardware for [Phil]‘s build is a Freetronix EtherTen, an Arduino clone with a built-in Ethernet interface. Aside from that, the electronics are simple: a relay, transistor, and diode provide the connection from the EtherTen to the garage door opener.

The software for this setup consists of a main file that sets up the web page, the serial monitor, and loops through the main program. There are a bunch of classes for initializing the web page, writing passwords to the EEPROM, activating the door, and setting the MAC and IP addresses.

Opening the door with this remote is a snap: with any WiFi enabled smartphone or tablet, [Phil] only needs to log onto his network, surf on over to the page hosted on the Arduino, and enter a password. From there, opening the door is just a press of a button. Passwords and other configuration settings cane be entered with MegunoLink. This software also includes a serial monitor to log who opened the door and when.

It’s an interesting and compact system, and handy to boot. You might sometimes forget your garage door opener, but we’re thinking if you ever find yourself without your phone, a closed garage door is the least of your problems.

Filed under: Arduino Hacks, wireless hacks


It’s no secret that I enjoy kit reviews – it’s always interesting to see how well a kit goes together, along with the quality of parts, documentation and so on. But what about kits from the past? And not 2003. Recently a very rare opportunity to purchase a sealed Sinclair Radionics Cambridge calculator kit appeared on ebay – so it was ordered rapidly and duly delivered to the office. And thus the subject of this review.

You may be familiar with the Sinclair name – Sir Clive Sinclair introduced many innovative and interesting products to the UK and world markets in his own style. Some were a raging success, such as the ZX-series home computers – and some were not. However in 1973 Sinclair introduced a range of calculators, starting with the “Cambridge”. It’s a simple four-function calculator with an LED numeric display and a somewhat dodgy reputation.

The design evolved rapidly and at the Mark III stage it was sold assembled and as a kit. At the time handheld calculators were quite expensive, so the opportunity to save money and get one in kit form would have been quite appealing to the enthusiast – in January 1974 the kit retailed in the UK for 24.95 (+ VAT):

Sinclair Cambridge Calculator Kit advertisement


Putting the Cambridge together required a balance of healthy paranoia, patience and woodworker mentality (measure twice – cut once). There wouldn’t be any second chances, or quick runs down to Altronics for a replacement part (well … there was one) so care needed to be taken. If you’re curious about the details, I’ve uploaded 82 full-resolution images from the build, including both instruction manuals and schematic onto flickr. Now to get started.

 The kit arrives in a neat, retail-orientated package:

Sinclair Cambridge Calculator Kit box

… with the components on one side of the foam:

Sinclair Cambridge Calculator Kit contents

… and the other side held he assembly guide (underneath which was a very short length of solder and the carrying case):

Sinclair Cambridge Calculator Kit guide

At this point I was starting to have doubts, and thought it would be better off in storage. But what fun would that be? So out with the knife and the shrink-wrap was gone, revealing the smell of 1974 electronics. Next to whip out the instructions and get started:

Sinclair Cambridge Calculator Kit instructions

They are incredibly detailed, and allow for two variations of enclosure and also offer tips on good construction – as well as the schematic, BOM and so on. Like any kit it’s wise to take stock of the components, which gave us the PCB:

Sinclair Cambridge calculator PCB

Sinclair Cambridge calculator PCB bottom

… the passives, diodes and transistor – and some solder wick:

Sinclair Cambridge Calculator Kit

At this point it turned out the all but one of the resistors were anywhere near the specified values in the instructions, and I wasn’t going to trust those electrolytic capacitors after 39 years. The replacement parts were in stock – including the original 1n914 diode that was missing from the kit. Thanks Clive. There was also a coil of unknown value:

Sinclair Cambridge Calculator Kit coil

… and the ICs, which included the brains of the operation – a General Instrument Microelectronics CZL-550:


… and an ITT 7105N:

ITT 7105N

… a bag of battery clips, buttons and adhesive-backed foam (which deteriorated nicely):

Sinclair Cambridge buttons battery cliips

At this point it was time to fire up the Hakko and start soldering, not before giving the PCB a good hit with the Servisol cleaner spray. I was worried about the tracks lifting while soldering due to heat and old-age, however the PCB held up quite well. The first step is to solder in the clips that hold (just) four AAA cells:

Sinclair Cambridge battery clips

… then the resistors and diodes:

Sinclair Cambridge calculator resistors

… followed by the transistor, ITT IC, ceramic capacitor and coil:

Sinclair Cambridge calculator assembly

Uh-oh – that ceramic went in the wrong hole. One leg was soldered where the coil was to sit. Without wanting to damage the PCB, de-soldering it was a slow, slow process. Then of course I didn’t have a ) 3.3nF in stock, so a quick spin to Altronics solved that problem (I bought 50) – one of which finally went in:

Sinclair Cambridge assembly

The transistor was also a bit of a puzzle, I hadn’t seen that enclosure type and the manual wasn’t much help, so the semiconductor analyser tester solved that problem:

transistor analysis

The next step was to fit the display, which is wedged in the large gap at the top of the PCB. The tracks on the PCB are supposed to meet the display, however time had affected the tracks on the display module, so I soldered small wire links across the gaps:

Sinclair Cambridge Display installation

Following the display were the two (new) electrolytics:

Sinclair Cambridge electrolytic capacitors

And now to the main IC. There wasn’t any second chances with this, and after some very gently pin-bending it dropped in nicely:

Sinclair Cambridge CZL550

After a short break it was time to assemble the keypad, which went smoothly. After cleaning all the foam dust off the buttons, they dropped in to their frame which in turn dropped into the enclosure, followed by the keypad layers:

Sinclair Cambridge keypad installation

You can also see in the display window and shroud have been fitted. From here the PCB is inserted:

Sinclair Cambridge assembly

… and a sticker from years gone by, as well as the metal clip over the bottom of the power switch. At this point a quick test with four AAA cells showed signs of life on the display, so the rear enclosure could be fitted:

Sinclair Cambridge Calculator

Now for the battery and final cover, and it’s ready to go!

Sinclair Cambridge Calculator

The digits are quite sharp, but very small – and set back from the window. This makes photography quite difficult. At the time if your calculator didn’t work, you could send it off to Sinclair and they’d repair or possibly replace it for you:

Sinclair Cambridge return form

Using the Cambridge

Well it works, so you have a calculator which is genuinely useful. However the Cambridge has a few quirks, which are attributed to the basic functions of the main IC. For example, when entering numbers the screen is filled with leading zeros until you select a function, however by using the manual you can complete complex work including square roots, percentages, loan repayments and much more.

Furthermore the Cambridge is quite the silent achiever, you can work with numbers as small as 1x10E-20 and up to 9.9999999E79. You simply enter the numbers in decimal form (e.g. 0.000000000123) … even though the display won’t show all the digits, they’re being stored in a register. To then extract the result, you continually multiply or divide by ten (making note of how many times you do that) until the digits appear on the screen. It sounds nuts today – but in 1974 it would have been a cheap way of avoiding a more expensive calculator. In the following video you can see th Cambridge in action, plus the results of dividing by zero:

More about Sinclair

The following video is a BBC dramatisation of the rise of the home computer in the UK market, and the competition between Sir Clive Sinclair (Sinclair) and Adam Curry (Acorn Computers) – which is quite entertaining:

You can find out more about the history of Sir Clive Sinclair here, and the calculator range here. If anyone can connect us with a Science of Cambridge MK14 computer, contact us.


From a 1974 perspective, that would have been a great kit to make, with some love and care it would have been successful. By today’s standards it was quite average – however you can’t really judge it from a 2013 perspective. Nevertheless, kudos to Sir Clive Sinclair for his efforts in knocking out a useful product as a kit. If you’re a collector, and see a sealed unit on ebay or elsewhere, give it a whirl. Just take your time, “think before doing”, and replace as many of the components as possible. I’ve put all the images in full resolution up on flickr, so you can follow along in more detail.

And while you’re here – are you interested in Arduino? Check out my new book “Arduino Workshop” from No Starch Press.

In the meanwhile have fun and keep checking into Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column? And join our friendly 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 Kit Review – Sinclair Cambridge Calculator appeared first on tronixstuff.

With the dispatch of the AuroraWatch schools' magnetometers imminent I have implemented a  Python  toolkit to process the data. The numpy and matplotlib modules are used extensively. The toolkit provides an API to load data and perform various processing actions on it, such as plotting data. The concept is influenced by my previous Multi-instrument Analysis toolbox for Matlab. In addition to the loading and processing of magnetic field data auroraplot allows other data types to be added later.

Loading data

Data can be loaded with arbitrary start and end times very simply:

md = ap.load_data('AURORAWATCHNET', 'LAN1', 'MagData',

In this case the selected portion of data crosses midnight and two data files must be loaded, concatenated and trimmed to get the desired time range. This is performed automatically by auroraplot, the user need not be concerned with the format of the files or where they are located. It is even possible for the files to be downloaded on-the-fly using FTP or HTTP transfer protocols.

load_data returns an object (of type MagData) to the user containing the actual magnetic field data and various other metadata, such as a timestamp for each sample and the data units. Each object can store more multiple data channels but all data points must share the same timestamps, be of the same type and share the same units. Therefore it is not possible to store operating temperatures (units °C) in an object holding magnetic field strength (units tesla). The operating temperature data can be accessed as:

td = ap.load_data('AURORAWATCHNET', 'LAN1', 'TemperatureData',

Battery voltage (data type VoltageData) can be accessed in a similar same way.

Plotting data

High-level plot functions enable the data be be plotted very simply, for the magnetic field data loaded previously


will produce a matplotlib figure with a title and the axes labelled with the correct units. Temperature and voltage data are plotted in the same way.

I have created some tools to make working with numpy's datetime64 and timedelta64 objects more convenient, including rounding functions (round, ceil and floor) which round to an interval. They are useful for finding the start of an hour, or the end of a day. I have also created Locator and Formatter classes to sensibly label time axes using datetime64 times and timedelta64 intervals. Tick marks are located on the nearest second, minute, hour, day, month or year boundary (or multiple thereof) depending on the time interval being displayed. Thanks to matplotlib's structure the labels are automatically regenerated with the most appropriate time units when a plot is zoomed.

Other operations

Quiet-day curves

Other operations include the generation of quiet-day curves. These are the curves from which we measure geomagnetic activity and are of critical importance for AuroraWatch UK. There are are not flat but have a daily variation caused by the equatorial electrojet. The empirical algorithm selects the days (typically 5) with the least geomagnetic activity. A truncated Fourier series is used to guarantee that the quiet-day curves are cyclic, with the start and end points having the same magnitude and slope. This is essential otherwise our rolling plots would show up the discontinuities in the QDC at midnight, and would falsely cause step changes in the geomagnetic activity. An example QDC is shown below.

Quiet-day curve for magnetometer at Lancaster ,UK. This is derived from recorded data
and clearly shows the Sq current system caused by the equatorial electrojet.

From this we can see that even on a geomagnetically quiet day we would expect a 30nT variation in field strength seen by the magnetometer. The AuroraWatch threshold for minor geomagnetic activity is 50nT so this shows the importance of using a quiet-day curve instead of a flat line when calculating geomagnetic activity.

Stack plots

Stack plots (also called magnetograms) are a convenient representation for magnetic field data from a set of magnetometers separated in latitude.Data from the northernmost instruments is placed at the top and that from the southernmost at the bottom. An example stackplot is shown below:

Stackplot showing data from two Lancaster stations and from Ormskirk.
The magnetometer at Ormskirk is operated by the Met Office as part of a test. The stackplots will be more interesting as the network grows.

Open source

The source code is available under a BSD-type license from Github.You will need python, along with the numpy (version 1.7), matplotlib and scipy python modules.auroraplot has been tested under Debian Linux (64 bit version) and Raspbian on the Raspberry Pi.