Author Archive

RFID Logic Puzzle

Posted in 9. Project Proposals on November 3, 2009 by ndoiron

Hopefully I can present this Thursday, as I haven’t had time to do the “hardest part” portion since I thought of the concept. Also would like more time to think about the technological part.

The idea is a logic puzzle where the objective is to find the correct pattern, sort of like MasterMind. The game would be a box. There are multiple ways to insert a piece into the game box (pushing through a door, revolving wheel) and the Arduino will sense how the player added a piece. Then, RFID technology reads the piece as it slides into a holding area. This means a game can be based on order of pieces, order of insertion, or a combination of the two.

To be honest, I need to design a better use of the RFID reader. I just realized that the reader handles one at a time, and am working on a number of ways that pieces could be used inside or outside of the box.

The hardest part will be designing the mechanical parts of the puzzle, because it involves building the components and designing them so that they compose a game.

Update: got RFID reader and tags in the mail, used to get it working. Reads all 4 tags that I have currently.


State Machine: Trick or Treat

Posted in 8. Finite State Machines on November 2, 2009 by ndoiron

This Halloween themed state machine has two of the more obvious states (trick vs. treat) and a third, more passive state (no one is at the door).

The planned sensors and actuators are shown in this Paint diagram:
Oreo Trick or Treat

When someone arrives at the door, the program leaves the passive “no one at door” state. The visitor makes their intentions clear with a switch (trick vs. treat) which is displayed on a lit sign. In the “treat” state, the dispenser rolls out a tray of Oreo cookies. When the visitor leaves, the passive state resumes and the tray retracts. The “trick” state isn’t particularly useful with the current actuators; mostly it waits for the trickster to leave or request a treat.

I built all of the parts and programmed them, but the Oreo-dispenser doesn’t work on its own.

The Oreo Dispenser
Oreo-Serving Servo

The Door
Picture 24

The Circuit Board
Picture 25

Download Code

Assignment 6: Frownobot

Posted in 6 Form & Motion on October 8, 2009 by ndoiron

Frownobot’s body is made up of a steam strainer (kind of a collapsible metal thing) and a light-up face. When the IR sensor detects a source (most likely from a TV remote), it runs a servo which turns the strainer until the remote control’s signal stops. If the servo turns too far and could twist the wires, Frownobot lights up his frowny face (to let the user know why it isn’t responding) and reverses direction.
Arduino board
A cardboard disk connects the little feet on the steam strainer to the servo shaft
Funny story about the strainer – when I was little, I would play with our strainer because the circular folding mechanism was just fascinating. My mom would always say, “you can’t play with that, it’s for the kitchen.” It was like Christmas morning when I found one for this project.
I originally wanted the strainer to be opened and closed by the motor, but I couldn’t find the right mechanism. Instead I added a bend sensor to the basket to detect whether a person has left it open or closed.
Dish and Remote
It looks like a jellyfish.
Code in comments. Servo, sensors, and LED are all wired directly to Arduino ports so the circuit diagram isn’t particularly interesting.

Analog I/O Project

Posted in 4. Analog Input-Output on September 24, 2009 by ndoiron

OK, I made the analog and serial port programs, and demo’d them.  They’re clearly lacking the spirit of color-mixing, though, as I’ve forgotten to have a translucent bulb-thing for them!  This’ll have to do until I do a retake, probably tomorrow.

Code Parts: 1, 2, 3, and 4.

Digital I/O: Box Switch

Posted in 3. Digital Input-Output on September 17, 2009 by ndoiron

I made a switch (SPST) from the small box my Arduino charger came in.  When the box is closed, the switch returns 1.  When the box is open, the switch returns 0.

The step/reset and counter programs are demonstrated in the YouTube video.  My second switch was a large toggle switch that I bought.

I probably should have used a sturdier box for my switch, or made it activate by flattening it to one side or the other.  Also, I learned that you can’t upload to the Arduino while digital ports 0 and 1 are connected to sensors.

“Inverse Alarm” Clock

Posted in 2. Buttonless Clock on September 8, 2009 by ndoiron

This buttonless alarm clock is set by ringing a small gong.

When the gong is hit with the attached mallet, the time begins moving forward rapidly (essentially “set” mode).


As the gong sound gets quieter, the time increase slows down…

until the sound diminishes to nothing or is silenced by the user (returning clock to “display” mode).


I call it an “inverse alarm” clock because the noise it makes is intended for the clock, not the user.