Stoplight controller details

It’s been a long time since I promised myself that I would post details of the stoplight controller. The controller is based on the Arduino Duemilanove, with a custom shield containing relays and connectors for the sensors.

The lights in the stop light itself are turned on and off by six 3A, 120V relays on the shield. The shield also has an independently controlled set of six LEDs and a few miniature buttons, mirroring the function of the main lights, switches, and sensors. The controller is housed in an 8″ plastic electrical box with a lexan cover. I have a bit of work to do yet to tidy up the wiring and strap down the transformer inside the box, but the  I cut a large hole in the side to hold the connectors for the sensors and button box, which use color-coded cat‑5 ethernet cables.

The distance sensors are Maxbotix LV-EZ1, which put out an analog signal that the shield passes along to the Arduino. The distance sensors fit perfectly inside these surface mount ethernet boxes with a 1/2″ hole drilled in them. Adding keystone jacks to the boxes makes connecting cheap cat‑5 cables simple and tidy. The sensors are mounted in front of each parking space. The Arduino runs a simple serial port interface program that can be used to program the controller with the threshold distances that change the light colors. The threshold distances are saved to the Arduino’s internal nonvolatile memory. The Arduino is positioned in the box such that the USB port is accessible from the outside, making updates and reprogramming simple.

The garage door open sensor is a C&K Components MPS80WGW magnetic switch. When the garage door opens, the magnet attached to the door moves away from the switch mounted by the door track, telling the controller that the garage door has opened. The controller then goes into parking mode, and changes the lights from green to yellow to red as the car pulls in.

A separate button box houses a couple great clicky arcade buttons that can make the controller perform some different light shows. The box is a simple 4″ grey plastic electrical box from the hardware store with a couple holes drilled in it, making it very durable.

links for 2010-07-27

  • The Stoker is a device that controls your cooker similar to the way your oven is controlled. A temperature sensor is placed in the cooking chamber where you want your temperature controlled. A blower is placed so air is blown into the firebox. The Stoker turns the blower on and off to “stoke” the fire to keep the temperature sensor at the set point.
    (tags: bbq)

Separated only by some years

Like father, like son, right?

links for 2010-07-08

  • Mapplers is an atlas of hand drawn maps. It is an ongoing project, continuing to collect maps and adding new areas when there is enough corresponding map data.
    (tags: maps)