Part Review – Freetronics TwentyTen “Duemiladieci”

Hello readers

Today we are going to examine the Freetronics “2010″ (Duemiladieci in Italian). This is a 100% Arduino Duemilanove-compatible board with some very neat enhancements. It was conceived by two Arduino experts here in Australia, Jon Oxer (co-author of the fascinating book “Practical Arduino“) and Marc Alexander. These two gentleman have formed Freetronics to help people build the projects detailed in the Practical Arduino book, assist people in releasing their hardware designs and generally help accelerate the open-source hardware movement. Jon and Marc were recently interviewed about Freetronics and the 2010 by Marcus Schappi, a copy of which can be viewed here.

But for now, back to the 2010. First of all, let’s have a look:

At first glance you may think “oh, just another Arduino clone”. Not so, however it is 100% compatible with the Arduino Duemilanove, so you can use the 2010 without any modification. Nevertheless upon closer inspection there are several small and large differences. The first thing to notice is the prototyping area. By doing some clever PCB routing, the designers have made space for a small but handy area for you to add your own circuitry. Here is a close up look:

Furthermore the corners have been rounded off, a small but thoughtful modification. The designers have also made the effort to label everything clearly, including the voltage and socket polarity for DC input, very handy for the beginner. And to make life easier, those large copper pads on the rear are for the 5V power and GND, so voltage supply is taken care of for you.

For an example of the prototype area use, check out my DS1307 real-time clock modification!

It is obvious that this board has been designed by people who use the Arduino system and not some knock-off manufacturer from eBay. The next visible differences are around the USB socket:

Those four holes are the X3 programming pads, much easier to use than the solder pads on the original Duemilanove. The purpose of these is to allow you to use your 2010 board as an AVR programmer, in order to program the bootloader into the microcontroller. Speaking of which, this is the ATmega328, identical to the Duemilanove’s chip. Next to the X3 pads is a mini-USB socket. In my case I love it, as when making my own shields I often need all the under-shield space I can use. For example:

And don’t worry about not having the correct USB cable, as one is supplied with the 2010. Subjectively, being one metre long, it could be longer. But you cannot please everyone!

Also note that the 2010 board has another mounting hole just behind the DC power socket, which increases stability if used in a more permanent situation. Moving around to the tail end of the 2010, the four LEDs have been placed here – allowing them to stay visible even with shields on top.

The power LED is a nice blue colour as well, TX is yellow, RX is green, and D13 is red. The circuitry for the D13 LED has been modified slightly, it will not come on when digital pin 13 is used as an input. Otherwise, everything else is in the correct, identical position to the Arduino Duemilanove. So all your shields will work, the ICSP (in circuit serial programmer) pins are in the same spot, and the pin current ratings and board input voltage range is identical. The complete specifications can be found here: 2010.pdf.

Another TwentyTen user has even over-clocked their board to 22 MHz. Amazing.

In conclusion, this is a board that is faithful to the Arduino design and improves on it. After using this board over the last ten days I can happily say it has worked flawlessly and all my sketches and shields have been compatible with the 2010. If you need another Duemilanove board, I can honestly recommend this one as a product of choice.

It is available directly from Freetronics, or other retailers including Little Bird Electronics.

High resolution photos are available on flickr.

As always, thank you for reading and I look forward to your comments and so on. Please subscribe using one of the methods at the top-right of this web page to receive updates on new posts. Or join our new Google Group.

Getting Started with Arduino! – Chapter Eight

Please note that the tutorials are not currently compatible with Arduino IDE v1.0. Please continue to use v22 or v23 until further notice. 

This is part of a series titled “Getting Started with Arduino!” by John Boxall – A tutorial on the Arduino microcontrollers, to be read with the book “Getting Started with Arduino” (Massimo Banzi).

The first chapter is here.

Welcome back fellow arduidans!

This week we will continue to examine the features of the DS1307 real time clock, receive user input in a new way, use that input to control some physical movement, then build a strange analogue clock. So let’s go!

Recall from chapter seven, that the DS1307 is also has an inbuilt square wave generator, which can operate at a frequency of 1Hz. This is an ideal driver for a “seconds” indicator LED. To activate this you only need to send the hexidecimal value 0×10 after setting the date and time parameters when setting the time. Note this in line 70 of the solution for exercise 7.1. This also means you can create 1Hz pulses for timing purposes, an over-engineered blinking LED, or even an old-school countdown timer in conjunction with some CMOS 4017 ICs.

For now, let’s add a “seconds” LED to our clock from exercise 7.1. The hardware is very simple, just connect a 560 ohm resistor to pin 7 of our DS1307, thence to a normal LED of your choice, thence to ground. Here is the result:

Not that exciting, but it is nice to have a bit more “blinkiness”.

Finally, there is also a need to work with 12-hour time. From the DS1307 data sheet we can see that it can be programmed to operate in this way, however it is easier to just work in 24-hour time, then use mathematics to convert the display to 12-hour time if necessary. The only hardware modification required is the addition of an LED (for example) to indicate whether it is AM or PM. In my example the LED indicates that it is AM.

Exercise 8.1

So now that is your task, convert the results of exercise 7.1 to display 12-hour time, using an LED to indicate AM or PM (or two LEDs, etc…)

Here is my result in video form:

and the sketch.

OK then, that’s enough about time for a while. Let’s learn about another way of accepting user input…

Your computer!

Previously we have used functions like Serial.write() and Serial.print() to display data on the serial monitor box in the Arduino IDE. However, we can also use the serial monitor box to give our sketch data. At first this may seem rather pointless, as you would not use an Arduino just to do some maths for you, etc. However – if you are controlling some physical hardware, you now have a very simple way to feed it values, control movements, and so on. So let’s see how this works.

The first thing to know is that the serial input has one of two sources, either the USB port (so we can use the serial monitor in the Arduino IDE) or the serial in/out pins on our Arduino board. These are digital pins 0 and 1. You cannot use these pins for non-serial I/O functions in the same sketch. If you are using an Arduino Mega the pins are different, please see here.  For this chapter, we will use the USB port for our demonstrations.

Next, data is accepted in bytes (remember – 8 bits make a byte!). This is good, as a character (e.g. the letter A) is one byte. Our serial  input has a receiving buffer of 128 bytes. This means a project can receive up to 128 bytes whilst executing a portion of a sketch that does not wait for input. Then when the sketch is ready, it can allow the data to serially flow in from the buffer. You can also flush out the buffer, ready for more input. Just like a … well let’s keep it clean.

Ok, let’s have a look. Here is a sketch that accepts user input from your computer keyboard via the serial monitor box. So once you upload the sketch, open the serial monitor box and type something, then press return or enter. Load this sketch. Here is a quick video clip of it in operation:

Notice in the line Serial.print(character, BYTE); that we force the display to byte, this is to show the value as the matching ASCII character; otherwise it would return the ASCII value of the character instead. For the young ones out there, please read this for an explanation of the ASCII table.

So now we can have something we already know displayed in front of us. Not so useful. However, what would be useful is converting the keyboard input into values that our Arduino can work with.

Consider this example. It accepts an integer from the input of serial monitor box, converts it to a number you can use mathematically, and performs an operation on that number. Here is a shot of it in action:

If you are unsure about how it works, follow the sketch using a pen and paper, that is write down a sample number for input, then run through the sketch manually, doing the computations yourself. I often find doing so is a good way of deciphering a complex sketch. Once you have completed that, it is time for…

Exercise 8.2

Create a sketch that accept an angle between 0 and 180, and a time in seconds between 0 and (say) 60. Then it will rotate a servo to that angle and hold it there for the duration, then return it to 0 degrees. For a refresher on servo operation, visit chapter three before you start.

Here is a video clip of my interpretation at work:

and the example solution sketch.

So now you have the ability to generate user input with a normal keyboard and a PC. In the future we will examine doing so without the need for a personal computer…

Finally, let’s have some fun by combining two projects from the past into one new exercise.

Exercise 8.3

Create an analogue clock using two servos, in a similar method to our analogue thermometer from chapter three. The user will set the time (hours and minutes) using the serial monitor box.

Here is a photo of my example. I spared no expense on this one…

My interpretation of the answer is here. And of course a video demonstration. First we see the clock being set to 12:59, then the hands moving into position, finally the transition from 12:59 to 1:00.

If you had more servos and some earplugs, a giant day/date/clock display could be made… If you like different clocks, have a look at these kits.

Nevertheless, we have had another hopefully interesting and educational lecture. Or at least had a laugh

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