These are my preliminary e-textile notes and they are a "work in progress."
- Nancy
Definitions
- Voltage (V) is analogous to pressure on a water system.
- Current (mA) is analogous to flow on a water system.
- Resistance:
- The flow of current is limited by resistance.
- A resistor can be used to control the flow of electricity (like a fawcet).
- When working with wires, you tend not to worry about resistance because the resistance on a wire is extremely low.
Resistance is a factor in e-textiles because the greater resistance values associated with conductive thread serve to limit the flow of electricity (like the interior quality of a water pipe).
- Circuit:
- Every circuit consists of a power source (battery) and a wire that supplies power to the LED and a wire running back to the battery as ground.
- Resistance must be calculated on the entire circuit (including round-trip on the conductive thread).
- Planning:
- Every LED has a minimum and maximum voltage rating and a current rating.
- If you install a series of lights on a wire, by definition, the first light will be the brightest and the last light will be the dimmest.
- Resisters are used to control electrical flow towards the impossible goal of making the light at the end of the wire as bright as the first light in the series.
- Threads used to create eTextiles have resistance so you need to calculate the resistance introduced by the distance electricity travels on the thread.
- You can make all of your LEDs the same brightness by running multiple wires of the same length in parallel from the power supply to individual LEDs. The ground wire can be shared.
- IR = E where
- I = Current
- R = Resistance
- E = Voltage
E-Textile Links
Supplies
- LEDs
| 1.8mm blue Led 1600MCD 80° Viewing Angle (Diffused) |
|---|
| Parameter | Min | Max | Unit |
|---|
| Luminous Intensity | 1200 | 1600 | MCD |
| Viewing Angle | 80° | 100° | Deg |
| Forward Voltage | 2.9 | 3.5 | V |
| Reverse Voltage | ~ | 5 | V |
| Forward Current | | 25 | mA |
| Wavelength | 665nm |
| Operating Temperature Range | -30° C to 80° C |
| Storage Temperature Range | -30° C to 80° C |
Lead Soldering Temperature
(4mm from body) | 260°C for 5 seconds |
| Color | Blue |
| Source =
http://www.unique-leds.com |
| 1.8mm white Led 5800MCD 30° Viewing Angle (clearwater) |
|---|
| Parameter | Min | Max | Unit |
|---|
| Luminous Intensity | | 5800 | MCD |
| Viewing Angle | | 30° | Deg |
| Forward Voltage | 3.0 | 3.5 | V |
| Reverse Voltage | ~ | ~ | V |
| Forward Current | | 20 | mA |
| Wavelength | --nm |
| Operating Temperature Range | -40°C to 80°C |
| Storage Temperature Range | -40°C to 80°C |
Lead Soldering Temperature
(4mm from body) | 260°C for 5 seconds |
| Color | White |
| Source =
http://www.unique-leds.com |
- Conductive Thread & Wire
- Numen Trace offers low resistance (9.5 ohms/foot or 38 ohms/meter) Conductive Thread
- ArtBeads.com offers 20 Gauge Bare Copper Artistic Wire
- Metal Crimp Beads: