Tag Archive | "leostick"

Project – Arduino “Book Monster”


Recently we saw a neat project by the people from Evil Mad Scientist – their “Peek-O-Book“, a neat take on a book with a shy monster inside, based on hardware from their Snap-O-Lantern kit. Not wanting to fork out for the postage to Australia we decided to make our own version, of which you can follow along.

This is a fun project that doesn’t require too much effort and has a lot of scope for customisation. There’s no right or wrong when making your own (or this one!) so just have fun with it.


First, you’ll need a book of some sort, something large enough to hide the electronics yet not too large to look “suspicious” – then cut the guts out to make enough space for the electronics. Then again it’s subjective, so get whatever works for you. Coincidentally we found some “dummy books” (not books for dummies) that were perfect for the job:

dummy book

After spraying the inside with matt black paint, the inside is better suited for the “eyes in the dark” effect required for the project:

dummy book internal

The “book” had a magnet and matching metal disk on the flap to aid with keep the cover shut, however this was removed as it will not allow for smooth opening with the servo.

The electronics are quite simple if you have some Arduino or other development board experience. Not sure about Arduino? You can use any microcontroller that can control a servo and some LEDs. We’re using a Freetronics LeoStick as it’s really small yet offers a full Arduino Leonardo-compatible experience, and a matching Protostick to run the wires and power from:

Freetronics Leostick and Protostick

By fitting all the external wiring to the Protostick you can still use the main LeoStick for other projects if required. The power is from 4 x AA cells, with the voltage reduced with a 1n4004 diode:

battery power and diode

And for the “eyes” of our monster – you can always add more if it isn’t too crowded in the book:

Arduino LEDs

We’ll need a resistor as well for the LEDs. As LEDs are current driven you can connect two in series with a suitable dropping resistor which allows you to control both if required with one digital output pin. You can use the calculator here to help determine the right value for the resistor.

Finally a servo is required to push the lid of the book up and down. We used an inexpensive micro servo that’s available from Tronixlabs:

Arduino servo

The chopsticks are cut down and used as an extension to the servo horn to give it more length:

Arduino servo mounted

Don’t forget to paint the arm black so it doesn’t stand out when in use. We had a lazy attack and mounted the servo on some LEGO bricks held in with super glue, but it works. Finally, here is the circuit schematic for our final example – we also added a power switch after the battery pack:

book monster schematic small

To recap  – this is a list of parts used:

After some delicate soldering the whole lot fits neatly in the box:

Arduino book monster final

Arduino Sketch

The behaviour of your “book monster” comes down to your imagination. Experiment with the servo angles and speed to simulate the lid opening as if the monster is creeping up, or quickly for a “pop-up” surprise. And again with the LED eyes you can blink them and alter the brightness with PWM. Here’s a quick sketch to give you an idea:

You can watch our example unit in this video.

Frankly the entire project is subjective, so just do what you want.


Well that was fun, and I am sure this will entertain many people. A relative is a librarian so this will adorn a shelf and hopefully give the children a laugh. Once again, thanks to the people from Evil Mad Science for the inspiration for this project – so go and buy something from their interesting range of kits and so on.

And if you enjoyed this article, or want to introduce someone else to the interesting world of Arduino – check out my book (now in a third printing!) “Arduino Workshop”.

visit tronixlabs.com

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 forum – 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.

Posted in arduino, evil mad science, freetronics, leostick, projects, tronixlabs, tronixstuff, tutorialComments (0)

Kit review – the Freetronics CUBE4: RGB LED Cube


LED cubes are a fascinating item, no matter where you come from the allure of blinking LEDs in various patterns is always attractive. And making your own is a fun challenge that most people can do after some experience with electronics hardware. However most people use single-colour LEDs, as wiring up RGB units triples the complexity of the circuit. Until now.

After much anticipation Freetronics have released their CUBE4 RGB LED cube kit – a simple to assemble and completely-customisable RGB LED cube:


Unlike other cubes on the market, this one includes an on-board ATmega32u4 microcontroller with Arduino Leonardo-compatible bootloader and a microUSB socket (… and a lot more) – so you don’t need anything extra to get started. And this gives you many more options when you’re ready to expand. But first let’s put it together and then get it working. Furthermore, keep reading to find out how you can have a chance to win your own Cube4.


Inside the box are all the parts needed for the kit, even a microUSB cable to power the Cube4 and also communicate with it:


There’s 64 RGB LEDs in that bag, so get ready for some soldering. The base PCB is well laid out, labelled and gives you an idea for the expansion possibilities:


Plenty of room to add your own circuitry – and the bottom:


As you can see in the image above, there’s an XBee-compatible pinout if you want to add communication via wirless serial link, plenty of prototyping space for your own additions and many other ports are brought out to open pads. There’s even a 5V supply pair to test LEDs, and a blue “power on” LED (which can be deactivated if necessary by cutting a track on the PCB).

The first job is to mount the LEDs on their plane PCBs – there are four, one for each horizontal plant. It’s very important to get the LEDs in the right way round, and there’s markers on the PCB that you can match up the longest leg of the LED with:


From experience I found it best to insert all the LEDs:


…and then do a final mass check of the alignment – which is easy if you hold the plane up to one side and compare the legs, for example:


At this stage it’s a great idea to double-check your LED alignment. After a while you’ll have the LEDs soldered in and trimmed nicely:


The next step was getting the vertical sticks aligned in order to hold the LED planes (above). Each stick is for a particular spot on the PCB so check the label on the stick matches the hole on the PCB. It’s incredibly important to make sure you have them perfectly perpendicular to the PCB, so find something like a square-edge or card to help out:


Once you have a row of sticks in you can start with a plane then insert a stick on the other side, for example:


Note the use of the elastic band to hold things together – they really help. Then it’s a simple matter of adding the planes and holding it together with another band:


… at which point you can do a final check that all the planes and sticks are inserted correctly. Then solder all the copper spots together and you’re done.

Don’t forget to turn the cube upside-down as there’s soldering to be done on the bottom of the planes as well:


 Although it might look a little scary, the final assembly isn’t that difficult – just take your time so it’s right the first time. You can view the following video which describes the entire process:

Once you’re confident that all the soldering has been completed – double-check for joints that aren’t completely bridged with solder as they will affect the operation of the cube. Then you can plug in the USB cable and watch the preloaded test/demonstration sketch in action:

If all your LEDs are working, awesome. If not – check the soldering. If there’s still some rogues – check your individual LEDs. Some of you are probably thinking “well that isn’t too colourful” – the problem is the camera, not the Cube4. If you see it in real life, it’s much better.


There are two methods of controlling the Cube4. It is delivered with a preloaded sketch that runs the demonstration showed in the video above, and then accepts commands over a serial/USB connection. So you can simply plug it in, fire up a terminal program (or the Arduino IDE serial monitor) and send text commands to do various things. If you type “help ;” the syntax is returned which explains how you can do things:


This serial control mode allows control by any type of software that can write to a serial port. Furthermore any other external hardware that can create or introduce serial text can also control the Cube4. For example by mounting an XBee module underneath and linking it to the TX/RX lines gives you a wireless Cube4. By doing so you can control it with a Raspberry Pi or other system.

Furthermore the Cube4 is also an Arduino Leonardo-compatible board in the same way as a Freetronics LeoStick.  With the use of the Cube4 Arduino library you can then create your own sketches which can visualise data with very simple to use functions for the Cube4. There are some great example sketches with the library for some inspiration and fun. Over time I look forward to using the Cube4 in various ways, including adding an Electric Imp IoT device and making another clock (!).

More demonstrations

Check out this Argot IoT demonstration.


This is the most approachable RGB LED cube kit on the market, and also the easiest to use. You don’t need to understand programming to try it out – and if you do it’s incredibly versatile. A lot of work has gone into the library, API and hardware design so you’ve got an expandable tool and not just some blinking LEDs. For more information visit the Freetronics website.  Larger photos available on flickr. And if you made it this far – check out my new book “Arduino Workshop” from No Starch Press.


The CUBE4 in this review is a promotional consideration from Freetronics. In the meanwhile 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? 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.

Posted in arduino, argot, cube, freetronics, jaycar, kit review, LED, leonardo, leostick, rgb, XC4274

First Look – the Arduino Leonardo


Recently the Arduino Leonardo was released, and I’ve finally got my hands on one. Some have claimed that the Leonardo as the successor to the Arduino Uno board, however that is somewhat subjective.  In this article we have a look for ourselves and examine the differences between the Uno boards that we’re used to and the new Leonardo.

The board

Here it is unwrapped from the cardboard packet:

It uses the same physical footprint as the Uno, so no surprises there:

 Now to travel around the board and see what’s new. First is the microcontroller – we have the Atmel ATmega32U4:

There are several pros and cons to using the 32U4. The pros include:

  • More analogue inputs. As well as the usual A0~A5, digital pins 4,6,8,9,10 and 12 can be configured as A6~A11
  • It handles USB. So no more external USB controller MCU or the old FTDI chip. Supposedly this saves money, however the retail price in some markets don’t reflect this
  • More PWM pins – well one more. They’re now on D3, 5, 6, 9, 10, 11 and 13
  • There is a little more SRAM than the Uno, it is now 2.5 kB
  • SPI has moved – they’re now wired to the ICSP pins. So you now have D10~D13 seperate to SPI
And the cons:
  • SPI has moved – they’re now wired to the ICSP pins. So if you have any shields that use SPI – too bad, they’re out. The most common example of this will be Ethernet shields – you’ll need to modify them with some jumper leads to contact the ICSP pins
  • I2C has moved over to D2+3. So if you have any shields using I2C – they’ll need to be modified
  • Less flash memory – the bootloader uses 4 kB of the 32 kB flash (the Uno used 0.5 kB)

However you can get an adaptor shield to use older Arduino shields with the Leonardo.

For MCU to Arduino pin mapping, see here. Next, for more on the USB side of things – as the 32U4 takes care of USB – take heed of the following notes from arduino.cc:

Since the Leonardo does not have a dedicated chip to handle serial communication, it means that the serial port is virtual— it’s a software routine, both on your operating system, and on the Leonardo itself. Just as your computer creates an instance of the serial port driver when you plug in any Arduino, the Leonardo creates a serial instance whenever it runs its bootloader. The Leonardo is an instance of USB’s Connected Device Class (CDC) driver.

This means that every time you reset the board, the Leonardo’s USB serial connection will be broken and re-established. The Leonardo will disappear from the list of serial ports, and the list will re-enumerate. Any program that has an open serial connection to the Leonardo will lose its connection. This is in contrast to the Arduino Uno, with which you can reset the main processor (the ATmega328P) without closing the USB connection (which is maintained by the secondaryATmega8U2 or ATmega16U2 processor).

There are some other changes to the board. Moving on, the next change is the USB socket. Do you recognise this socket?

Yes – micro USB. Thankfully (!) a growing number of mobile phones use this type for charging and USB connection, so you may already have a matching cable. Note that the Leonardo doesn’t include a cable, so if you’re an iPhone user – order yourself a cable with your Leonardo.

Next, the LEDs have been moved to the edge of the board. You can see them in the above image to the right of the USB socket. No more squinting through shields at strange angles to check the TX/RX lights. However this isn’t a new invention, our friends at Freetronics have been doing this for some time. Furthermore, the reset button has been moved to the corner for easier access.

There are also seperate connectors for the I2C bus – next to AREF, which should make modifying existing shields a little easier:

 Finally, due to the reduction in components and shift to SMD – there is what could almost be called a large waste of space on the board:

A few extra user LEDs wouldn’t have been a bad idea, or perhaps circuitry to support Li-Po rechargeable batteries. However the argument will be “that’s what a protoshield is for”. Just saying… As for the rest of the hardware, the specifications can be found here.

Finally, the Leonardo is available in two versions – with and without headers. This makes it easier to embed the Leonardo into fixed applications as you can directly solder to the various I/O pins. An alternative to this would instead be the Freetronics LeoStick, as it is much smaller yet fully compatible.


First – you need to drag yourself into Arduino IDE v1.0.1. Note you can run more than one version of the IDE on the same machine if you don’t mind sharing the same preferences file. Next, the Leonardo doesn’t reset when you open the serial monitor window (from arduino.cc) –

That means you won’t see serial data that’s already been sent to the computer by the board, including, for example, most data sent in the setup() function. This change means that if you’re using any Serial print(), println() or write() statments in your setup, they won’t show up when you open the serial monitor. To work around this, you can check to see if the serial port is open like so:

Using the 32U4, you also have two serial ports. The first is the emulated one via the USB, and the second is the hardware UART on digital pins 0 and 1. Furthermore, the Leonardo can emulate a USB keyboard and mouse – however with a few caveats. There is a section on the Leonardo homepage that you should really read and take note of. But this emulation does sound interesting, and we look forward to developing some interesting tools to take use of them, so stay tuned.


There is nothing wrong with the Leonardo board, it works as described. However you could consider this a virtual “line in the sand”, or a new beginning. Due to the changes in the pinouts shields will need to be redesigned, and for those of you still programming in Arduino v23 – it’s time to get up to speed with v1.0.1. If you need the special USB functions, keyboard and/or mouse emulation, or are happy with the changes and can get one for less than the cost of a Uno – great.

Here’s a video from the main man Massimo Banzi:

However if you’re looking for your first Arduino board – this isn’t the board for you right now. There are too many incompatible shields out there, and the inability to cheaply replace the microcontroller will see some beginners burn out their first couple of boards rendering them useless. Get yourself an Arduino Uno or compatible board such as the Freetronics Eleven.

In conclusion, classifying the Leonardo board as good or bad is not a simple decision. It may or may not be an improvement – depending on your needs. Right now – for beginners, this is not the board for you. For those who understand the differences between a Uno and Leonardo, sure – no problem. Frankly, I would get a LeoStick instead.  At the end – it’s up to you to make an informed decision.

In the meanwhile 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? 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.

Posted in arduino, atmega32u4, DEV-11286, leonardo, review, tronixstuff, tutorialComments (23)

Results – February 2012 Competition

Competition over.

Posted in competition

Is this the world’s smallest Arduino-compatible board?

Introducing the Freetronics LeoStick – one very small Arduino Leonardo-compatible** board, in the format of a typical USB memory stick – the board for integration into smaller projects, on-the-go fun when travelling, or minimalism-enthusiasts:

Whether or not the LeoStick is the world’s smallest Arduino-compatible board – it’s pretty darn tiny – for example:

Note that the length includes the USB plug extrusion on the PCB. A lot of small boards on the market may consider themselves to be fully Arduino-compatible, but with a few minor or major caveats – such as not having full USB interface, or using a cut-down MCU such as an ATtiny, or offer less current handling ability. After comparing their specifications with the LeoStick, you can see how much has gone into such a small board:

  • Native USB port built-in, no need for any USB or FTDI cables
  • Two Full Color RGB LEDs on-board! Drive different colored outputs and fun feedback from your sketch right away. One RGB LED is completely programmable, the other does Power, USB RX and TX indication, the RX and TX LEDs can also be controlled.
  • On-board Piezo speaker element, play sounds, tunes and beeps. Can also be used as a knock/vibration sensor
  • Same I/O pins. The LeoStick provides all the same header connections as larger boards, you can connect all the same sensors, actuators, and other inputs and outputs as typical Arduino models.
  • Breadboard compatible, has 0.1″ pitch pads and header pins can be fitted underneath
  • 500mA polyfuse and protection on the USB port
  • ATmega32U4 microcontroller, Arduino compatible with on-board USB, 32K Flash, 2.5K RAM, 1K EEPROM at 16MHz
  • ISP 6-pin connector for advanced programming of the ATmega32U4 MCU

Here is the underside of the LeoStick , showing the piezo speaker:

And here is a quick video of the LeoStick in action:

** Although this is a newly-released product, it does rely on a modified beta version of the upcoming Arduino Leonardo bootloader. There are some known issues with Windows 7 64-bit drivers and some library functions don’t work perfectly yet. Any firmware or Arduino Leonardo compatible support should not be considered to be final release firmware or in any way an official Arduino. At Freetronics’ request, please don’t hassle the Arduino team with support or requests related to this board – they’re solely the responsibility of Freetronics.

Nevertheless there is a growing and vibrant support forum where you can see examples of the LeoStick in action and discuss other subjects and issues. The LeoStick is also a very complete ATmega32U4 breakout and USB board by itself and the LeoStick can be programmed directly from the supplied standard ISP header by AVR Studio, Mac OSX-AVR, avrdude, WinAVR etc.

The LeoStick  is also new to us here as well, and we look forward to integrating it into projects in the near future, as well as having a board to experiment with when travelling. As we always say – if it meets your needs or you want to try something new, you could do a lot worse than getting yourself a LeoStickIf you are interested in learning how to use Arduino in general – check out our tutorial here. For more discussion and support information for the LeoStick consult the forum or product web page.

Disclaimer – The LeoStick board reviewed in this article was a promotional consideration made available by Freetronics

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.

Posted in arduino, freetronics, leonardo, leostick, review

February 2012 Competition

Competition over

Posted in competition

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