Lot’s of people are excited about the Raspberry Pi®, a complete computer for $25 (or $35 with ethernet).
The initial shipment is entirely sold out, and there are 200,000 more on order. Lots of people have been saying that this is the end of the Arduino, as it’s about the same cost, a full linux system with keyboard, mouse, and hdmi video output.
I think this is an oversimplification. Arduino is fantastic at interfacing to the physical world in a way that no linux (or Windows) PC could hope to approach at any cost.
The Pi does have a GPIO connector, but it pales in comparison to the humble Arduino. No built in PWM (servos anyone?) and no Analog to digital conversion.
Why throw the baby out with the bathwater? How about some delicious ice cream with your Raspberry Pi?
As a member of the amazing Open Source Hardare collective Wyolum.com, I’m working with Justin Shaw and Anool Mahidharia on “à la mode”: an Arduino clone specifically for the Raspberry Pi (That rendering above is courtesy of our fabulous EE Anool) . You can of course connect an Arduino to a Pi USB port, but when you want a turnkey solution, how about an Arduino compatible “plate” (what the Pi folks call shields) that fits right on top of the Raspberry Pi.
You can plug your existing shields right in, and you can even run the Arduino IDE on the Pi. Since the Pi’s core mission is to provide equal access to computing to all children, this will also give the kids the opportunity to mix it up “Arduino-style” with real world hardware.
We couldn’t have a vanilla add-on, so we added:
A battery backed real time clock: RTC: DS3231 (same as ChronoDot)
uSD card for logging
Socketed Atmel Atmega 328p in case you make a wiring mistake and need to replace it.
We’re sending off for prototype boards soon, so if you have feedback, let us know! Join the conversation at the Wyolum.com forums.
I’m a big fan of Scratch, the educational programming language created at MIT. International Scratch Day is coming up, and when we went two years ago, we had a blast. Last time, I added a distance sensor to an Arduino, made it emulate a Scratch Sensor Board, and put it under a trampolene. This year, I decided to document the general process of making your own scratch sensors and bring a compact sensor module for the kids to play with.
At one point during our research at work, we needed a way to measure the movement and relative distance of a camera platform, so I designed, and my tech put together a combination of a Teensy (Arduino Compatible microcontroller), an Adafruit ADXL335 Accelerometer breakout, and a Sharp IR distance sensor.
I dug up my old code for the trampolene hack, which was based on some code I got off the Scratch forums. It didn’t work!
What we are actually doing is emulating what was originally called a “Scratchboard” and now produced by a company called the Playful invention company and called a “PicoBoard”.
Turns out, the platform used to be more forgiving, and now it expects a report of all the sensors (whether we are using them or not.)
The IR distance Sensor outputs an analog voltage proportional to the distance to the nearest thing in it’s path, and likewise the accelerometer outputs a voltage proportional to the acceleration (including gravity). I mapped the distance sensor to the “slider” sensor, and the X, Y and Z outputs to the Resistance A, B and C sensors.
Here’s a demo video:
I’m planning on re-working the interface code into an Arduino Library, and I’ll post that here when I get it done.
In the meantime here’s the Arduino code:
// Scratchboard emulation
// by Kevin Osborn
// http://baldwisdom.com
// Feel free to use this code in any way you wish! (Though if you want to link
// to my blog, that would be cool)
// The Scratchmote has a sharp ir distance sensor
// and a 3 axis accellerometer
#define DISTSENSE A0
#define ACCELX A1
#define ACCELY A2
#define ACCELZ A3
#define TESTMODE 0
// Format output for ScratchBoard emulation
// sensor=0-7, value=0-1023 (rescaled by Scratch to 0-100)
// 0="A", 1="B", 2="C", 3="D",
// 4="Slider", 5="Light", 6="Sound", 7="Button"
void ScratchBoardSensorReport(int sensor, int value)
{
Serial.write( B10000000
| ((sensor & B1111)<>7) & B111));
delayMicroseconds(400);
Serial.write( value & B1111111);
}
int flatx,flaty,flatz; // might be used to set midpoint
int maxX,minX; //testing purposes
int lastx,lasty,lastz;
void setup()
{
pinMode(DISTSENSE, INPUT);
pinMode(ACCELX,INPUT);
pinMode(ACCELY,INPUT);
pinMode(ACCELZ,INPUT);
lastx =maxX= minX = flatx=analogRead(ACCELX);
lasty = flaty=analogRead(ACCELY);
lastz = flatz=analogRead(ACCELZ);
Serial.begin(38400);
}
void loop()
{
int distance = abs(map(analogRead(DISTSENSE),0,650,0,1023)-1023);
//experimenting with the ADXL335 gives us readings between low single digits
// and < 700 for human powered movements int x = map(analogRead(ACCELX),0,700,0,1023); int y = map(analogRead(ACCELY),0,700,0,1023); int z = map(analogRead(ACCELZ),0,700,0,1023); int rx = (x +lastx)/2; int ry = (y +lasty)/2; int rz = (z +lastz)/2; lastx = rx; lasty = ry; lastz = rz; #if TESTMODE Serial.println(distance); /* Serial.print("x,y,z= "); Serial.print(x);Serial.print(","); Serial.print(y);Serial.print(","); Serial.println(z); */ if (x > maxX) maxX=x;
if (x< minX) minX=x;
Serial.print("maxX = ");Serial.println(maxX);
Serial.print("minX = ");Serial.println(minX);
delay(500);
#else
if (Serial.available())
{
if (Serial.read() == 0x01){
ScratchBoardSensorReport(0,rx);
ScratchBoardSensorReport(1,ry);
ScratchBoardSensorReport(2,rz);
ScratchBoardSensorReport(3,0);
ScratchBoardSensorReport(4,distance);
ScratchBoardSensorReport(5,0);
ScratchBoardSensorReport(6,0);
ScratchBoardSensorReport(7,0);
}
//ScratchBoardSensorReport(1,analogRead(POT2));
// ScratchBoardSensorReport(7,digitalRead(BUTTON1)?0:1023);
delay(30);
}
#endif
}
Charlotte, Mason and I hopped into Cambridge last Friday for the Mini Maker Faire at the Cambridge Science Festival. They helped me set up a table to introduce DuckyBots! to the attendees. We had probably close to 500 kids (and a few adults) making ducky bots in the 4 hours of the Faire, and almost got into trouble because people didn’t want to stop. We were the last ones to shut down. An unqualified success! (more details after the picture)
Photo by Chris Conners
The idea for duckybots started from a conversation at the Boston Robotics Meetup with Meredith Garniss. In addition to trying to involve kids in robotics, we thought it would be good to inspire the adult robotics crew to create for kids.
Programs like FIRST robotics, and school programs are already full of people interested in STEM and robotics, and we wanted to find something that would turn kids on to the joys of Science and Engineering.
The basic idea is to use turning rubber ducks into robots as a platform for experimentation, creativity and learning.
We thought we could apply this at many ages and levels. Really young kids can exercise their creativity by decorating ducks (drawing, gluing on.)
The middle level would concentrate on mechanical physics, making ducks move, maybe racing (but also have to offer non-competitive challenges for kids scared of competition.)
To keep the ideas coming in, we can also have an advanced level, perhaps Sumo ducks (on water!)
For their first appearance, I needed an activity that could be be done by hundreds of kids in a short period of time, so I focused on “making them Move”
Rather than presenting them with a blank slate, I put together some modules that represent different propulsion types.
I created a fan unit from a toy motor, a AA battery box (with switch) and a fan propeller sold as a spare for snap circuits.
I also had some playmobil underwater motors, and lots of Duck(!) tape (especially yellow).
As kids strapped on the motors, and found the ducks tipping over, presenting an engineering challenge! I also had some closed cell foam (from packing materials) that they could use for floats, and outriggers.
There was lots of inventing, trying, doing things “wrong” (turns out those air fans work fine underwater!)
I was thinking that this was a good test to see if I should spend any more time on this, and I think the answer is yes!
