Programmable LilyPad EL-Wire Dress
Intro: Programmable LilyPad EL-Wire Dress
Nicole A. Wolfersberger and I, with support from Prof. Kylie Peppler at Indiana University, made a LilyPad Arduino-controlled EL-wire dress. With a few extra components we were able to control the blink frequency of the EL wire. This introduces the new possibility of controlling the EL wire via sensor (button, touch, temp, light, etc.). Now the EL wire doesn't simply have to be either on or off--it's ready to be programmed!
The LilyPad Electronic Platform is an electronic platform designed to be easily sewn into fabric using conductive thread, which provides designers freedom from the traditional construction method of soldering.
EL wire (electroluminescent wire) is a thin wire the glows when an AC voltage is applied. The wire is often wrapped in a colored transparent tube and is quite pliable. Many people often outline clothing (hats, pants, jackets, etc.) with EL wire, giving the garment an interesting colored glow. We, however, want to not only outline a garment but also control when the EL wire is lit.
Controlling the EL wire is not difficult but it does require some electronic pieces that everyday crafters may not be familiar with.
The LilyPad Electronic Platform is an electronic platform designed to be easily sewn into fabric using conductive thread, which provides designers freedom from the traditional construction method of soldering.
EL wire (electroluminescent wire) is a thin wire the glows when an AC voltage is applied. The wire is often wrapped in a colored transparent tube and is quite pliable. Many people often outline clothing (hats, pants, jackets, etc.) with EL wire, giving the garment an interesting colored glow. We, however, want to not only outline a garment but also control when the EL wire is lit.
Controlling the EL wire is not difficult but it does require some electronic pieces that everyday crafters may not be familiar with.
STEP 1: EL-Wire Difficulties
As mentioned before, the EL wire is only illuminated when an AC voltage is applied. Most, if not all, suppliers of EL wire also sell inverters necessary for this task. The inverter has a DC input and an AC output.
This is the beginning of our problem: how can we use the LilyPad to turn the EL wire on and off if the EL wire is controlled by an AC signal and the LilyPad uses DC? And the problem is often even more difficult, because the LilyPad board can be powered between 2.7-5.5 V. Inverters often have input DC voltages of 1.5V, 3.0V, and 12V, though input voltages range between 1.5V and 18V. Furthermore, if there is a spike or surge with the inverter it may damage the LilyPad.
This is the beginning of our problem: how can we use the LilyPad to turn the EL wire on and off if the EL wire is controlled by an AC signal and the LilyPad uses DC? And the problem is often even more difficult, because the LilyPad board can be powered between 2.7-5.5 V. Inverters often have input DC voltages of 1.5V, 3.0V, and 12V, though input voltages range between 1.5V and 18V. Furthermore, if there is a spike or surge with the inverter it may damage the LilyPad.
STEP 2: Optoisolator
First, let's tackle the voltage issue. Ideally, we would like to isolate the inverter and its power supply from the LilyPad and its power supply. That way, any surges in the AC line will stay on the EL wire side.
Luckily, good electrical engineers invented the optoisolator. Simply put, the optoisolator uses an IR LED to send an photon to a detector to control other side of the circuit. I used an NTE3044, which is an optoisolator with a Darlington pair. The Darlington pair is just two transistors in series.
If we connect the anode to a pin on the LilyPad, the cathode to GND of the LilyPad, and the collector to the Plus side of the inverter power supply, then we have effectively isolated the LilyPad from any dangerous spikes. The emitter will used as the trigger for the Triac.
Luckily, good electrical engineers invented the optoisolator. Simply put, the optoisolator uses an IR LED to send an photon to a detector to control other side of the circuit. I used an NTE3044, which is an optoisolator with a Darlington pair. The Darlington pair is just two transistors in series.
If we connect the anode to a pin on the LilyPad, the cathode to GND of the LilyPad, and the collector to the Plus side of the inverter power supply, then we have effectively isolated the LilyPad from any dangerous spikes. The emitter will used as the trigger for the Triac.
STEP 3: Triac
A triac is solid state device which allows for control over AC loads. If you apply a voltage at the Gate (G) relative to MT1 the triac will conduct from MT1 to MT2 as long as the current through the triac doesn't dip below a threshold hold value. I am using a MAC-97A triac which has a holding current of 5mA and a gate voltage of 2.0 V.
Every time I send a signal from the LilyPad to the optoisolator, that pulse is translated to a 2V pulse from the Darlington Pair. That pulse then opens the gate and grounds one side of the EL wire. That's okay, because we are going to connect the copper core directly to inverter. If you hold one line of the EL wire at GND and the other line receives the AC signal, the EL wire will still work because the AC signal will still be oscillating relative to something--in this case, the GND of the battery.
Every time I send a signal from the LilyPad to the optoisolator, that pulse is translated to a 2V pulse from the Darlington Pair. That pulse then opens the gate and grounds one side of the EL wire. That's okay, because we are going to connect the copper core directly to inverter. If you hold one line of the EL wire at GND and the other line receives the AC signal, the EL wire will still work because the AC signal will still be oscillating relative to something--in this case, the GND of the battery.
STEP 4: EL Wire
There are a number of Instructables dealing with the stripping, prepping, and soldering of EL wire. This is my favorite. I stripped off the blue plastic from the EL wire, revealing a copper core and a smaller clear plastic tube housing the angel wire. After carefully removing the clear plastic tube I glued some copper tape to the EL wire and soldered the angel wire to the copper tape. If I had some shrink wrap tubing I would have inserted that over the copper tape for protection.
After soldering test that the EL wire illuminate when connected directly to the inverter and the inverter is powered by the appropriate source.
After soldering test that the EL wire illuminate when connected directly to the inverter and the inverter is powered by the appropriate source.
STEP 5: Electronic Parts
We need the following:
- perf board
- solder
- soldering iron
- 330 Ohm Resistor
- NTE3044 Optoisolator Darlington Pair
- 6 or 8 pin socket
- Triac MAC-97A4
- 2xAA holder with 9V plug adapter
- jumper wires
STEP 6: Solder Components
Before soldering it's always a good idea to lay out your components on the board and see how they will fit together. I made a number of mistakes and had to solder on jumper wires.
Notes: I curled up one end of the resistor so that I could sew from a pin on the LilyPad to the resistor.
A cartoon diagram is provided below. I soldered the DC inputs of the inverter to the resistor, triac, socket, power supply connecter, and two jumper wires: one for the minus side of the LilyPad and one for the copper tape on the EL wire.
I will provide an eagle file soon.
Notes: I curled up one end of the resistor so that I could sew from a pin on the LilyPad to the resistor.
A cartoon diagram is provided below. I soldered the DC inputs of the inverter to the resistor, triac, socket, power supply connecter, and two jumper wires: one for the minus side of the LilyPad and one for the copper tape on the EL wire.
I will provide an eagle file soon.
STEP 7: Sewing and Soldering EL-Wire
Parts needed:
First decide on where the EL wire is going to be attached. We decided to simply outline the button of dress with the EL wire. Next sew the Lilypad and Power Supply to one another on the dress. Attach the perfboard with components, 3V power supply, and inverter to the dress (I used sticky back velcro). Lastly, solder the EL wire copper core to one side of the inverter and the angel wire to the jumper from the perfboard.
- LilyPad
- LilyPad Power Supply
- Conductive Thread
- El Wire
First decide on where the EL wire is going to be attached. We decided to simply outline the button of dress with the EL wire. Next sew the Lilypad and Power Supply to one another on the dress. Attach the perfboard with components, 3V power supply, and inverter to the dress (I used sticky back velcro). Lastly, solder the EL wire copper core to one side of the inverter and the angel wire to the jumper from the perfboard.
STEP 8: Testing and Finish
Once everything is connected, upload a simple code that pulses a pin on the LilyPad HIGH and LOW every 2 seconds. If the EL wire doesn't flash, first check that the voltage from the optoisolator's emitter pin is between 2-3 volts. If it's still not working double check that the EL wire is illuminated when connected directly to the inverter.
When it's done, you'll be able to control the flashing of the EL wire!
This material is based upon work supported by the National Science Foundation under Grant No. 0855886. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
When it's done, you'll be able to control the flashing of the EL wire!
This material is based upon work supported by the National Science Foundation under Grant No. 0855886. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
7 Comments
ShortedOut 13 years ago
FIRST QUESTION. Sorry, but it's really hard to look at the bunches of wire and soldering connections on the bottom of the perf board. Especially helpful is the diagram in your pics for Step 6, second picture from the left (the one with white background that shows the connection layout of the components). What I need to know, that isn't labeled in that diagram, is the purple and black lines going to the TRIAC---which is MT1 and which MT2 (assuming the center one is gate?)---and also the wires on the EL wire---which one is the purple line, the copper core or the angel? And is the bronze/brown-colored rectangle between the Lilypad and pin 1 of the optoisolator denoting the resistor? Sorry, this was a complicated first question!
SECOND QUESTION is how would you modify this project if the inverter takes a 12-volt power source instead of 3 volts? Any idea how to do that? Would the optoisolator and/or TRIAC have to be a different ones, or just set differently? Right now I am using a 12-volt 500 mA transformer, your basic wall wart, to provide power, rather than using batteries. I have the power going into a mini-plug jack (switched). Thanks for any help!
quasiben 13 years ago
FIRST ANSWER:
Looking at the triac with the flat side facing you the pins outs are:
1) MT1
2) G
3) MT2
Therefore, the black line, which is the the ground of the battery connected to the inverter is connected to MT1
It doesn't matter which lines go to to the copper core or the angle wire. One line will be grounded and the other will be alternating. That's the great thing about AC!
Yes, the bronze/brown colored rectangle is suppose to denote the resistor. See pic 3 on Step 6. I believe it's a 330 Ohm resistor.
SECOND ANSWER:
You may not need to change anything. For the optoisolator you need to make sure that you are getting around or above 2.0V from the emitter (pin 4) to get the triac to switch on. I would suggest putting in a resistor to limit the current. The first thing I would do is set up the circuit and measure the voltage coming from the emitter relative to ground of the wall wart.
Give me a few days I and will have a more proper answer for you.
chrisk364 6 years ago
hey. Great project. just one thing that I keep thinking about. Wouldn't this project still work with only an opto-isolator ? Whats the reasoning for the Triac, if you don't mind me asking.
alftonic 8 years ago
Nice..... any fire risk?
Jimmy Proton 13 years ago
mariosquad 12 years ago
ShortedOut 13 years ago
The reason for the 12-volt supply is that I bought these lights as computer case-modding supplies, and have been cutting off the molex connectors. Power from the 12v/500 mA transformer goes to a mini-jack, then plus-side goes to SPST rocker switch.
I'll have to do some thinking about how to power the LilyPad. My project is inside a case, which will make the LilyPad power supply hard to access...