Detour

Pasted to a wall of the city, this module simply indicates a direction with an arrow of LEDs. A button allows the person who installs it to select among the following:

1. Left
2. Right
3. Random change (50% chance to change direction every five minutes)

The object is completely self-sufficient. During the day, it goes into standby mode and ceases to emit light. A solar panel recharges the batteries. At night, the module awakens and uses the energy stored in the batteries.

Currently at the prototype stage, Detour is intended to be produced in large quantities in order to create networks that can reveal the unusual ways of passing, even absurd, through the city pathways.

Ingredients

• 10 x LEDs
• 10 x resistor (approx. 330 ohms)
• 1 x solar power circuit (see this page)
• 1 x ATMega8L
• 1 x button + 1kOhm "pull down" resistor
• 1 x photoresistor + 1 x "pull down" resistor (to be adjusted) or a potentiometer (optional)

Instructions

Circuit

Note: A detailed schema has not yet been produced, it is possible that these instructions are not completely accurate.

1. Place the 10 LEDs on a mounting plate so as to reproduce the shape shown in the image DiagramArrow.png.
2. Connect each LED to a digital I/O pin of the ATmega8 excepted PD0 and PD1 (which are used for interrupts). Put a resistor between each LED and pin. See this page for a detailed description of the correspondence between the pins available on the ATmega8 and those of the Arduino.
3. Connect the push-button to pin 2 (PD0) with 1kOhm "pull-down" resistor (ie. the reverse circuit presented here) .
4. Connect the photoresistor to pin 3 (PD1) with a "pull-down" resistor. This resistor must be adjusted so that the object is activated only at dusk. You can alternatively use a potentiometer (variable resistor).
5. Build the solar power supply and connect it directly to the circuit (we used in the initial solar battery of 4-5 V and 3 NiMH rechargeable batteries of 1.2 V, 3.6 V total).

Programming

1. Copy the attached files detour.pde, arrow_animation_data.h and Makefile.txt in a directory. You must have installed the Arduino libraries.
2. Change LED_PINS array to contain, in order, the numbers of the pins associated with each LED.
3. Compile: make
4. Configure the ATmega8 fuses with: make writefuse
5. Send the program to ATmega8: make upload

Each time you press the button, the object changes mode (left, right, random).

Attachment	Size
DiagramArrow.png	2.17 KB
detour.pde	9.51 KB
arrow_animation_data.h	2.42 KB
Makefile.txt	7.76 KB