Archive

Resistor "Pull-ups" and "Pull-downs" serve many purposes in electronics. A pull-up is a resistor with one end wired to a positive power rail. A pull-down has one end wired to ground or a negative rail. Here is a basic introduction with schematics. A wikipedia entry covers this but is full of arcana like ttl logic gates.

The basic design pattern for shunt-mode pressure sensing with piezo resistive materials is illustrated with fabric.

A second sensor improves on this design by interdigitating the conductors.

How to build a Tablo fabric gesture controller

This illustrates how to use malleable conductive materials and office supplies to make your own potentiometer any size you like.

A fabric pressure/touch sensor you can build yourself in seconds.

This kit for the 2008 class included materials for scratch assembly of sensors, a CUI board running uOSC and a few tools such as scissors.

The majority of acceleration/tilt sensors used these days are single integrated circuits MEMS devices. The cheap ones are made for air bag and other high volume applications. Although the chips are cheap ($5-10 Retail,<$1 in quantity), they are usually sold in surface mount packages that are inconvenient to work with without industrial quality tools.

Most sensing applications of e-textiles use switching, piezoresistivity or optics for direct touch sensing. This instructable shows you how to start exploring another approach - capacitive sensing to measure touch and proximity. It is based on the easy-to-use, cheap capacitance sensing chip evaluation board from Atmel/Qtouch and takes only minutes to create.

This is a strong fast and connection for prototyping with the Lilypad.

Dismantle 3 Gametraks and remove the pair of joysticks in each.
Ream out the paddle hole to match the diameter of conductive chord you selected for the strings. I used standard chandelier wire which required a slight enlargement of the hole.
Install the joysticks on the bridge, according to the height and string spacing you have chosen.
Drill the holes in the bridge to pass the chord through.

This digital multimeter is useful for evaluating textiles and thread for conductivity and electrical resistance.
Because each colored led have a different forward voltage different "scales are provided", Blue is good for low resistance,
Green for middle, and red for higher resistance.