Picture of Curved Circuit Board Art: Make a Touchless Touch-Switch LED Lamp
With a wave of the hand, turn on a USB powered touch-switch LED Lamp. You do not have to actually touch the sensor. It is so sensitive, it will activate by the presence of a finger an inch or two away. While the circuit described here is shown activating an LED Lamp, with the addition of a relay, it can be used to activate almost any electronic device when you turn on your PC.

This instructable also details how to make functional curved circuit boards that can serve as a case and a circuit.

It also shows a fast, easy and inexpensive way to etch patterns and solder able traces on any simple circuit board.

The video shows how the lamp is turned on and off.

The intro Pic shows the touch switch lamp on the left and some other etched curved circuit boards that await components.

Step 1: How It Works

Picture of How It Works
The touch switch circuit is based on the QT-113 integrated circuit. It works by detecting changes in capacitance. When it is first turned on it measures capacitance at its sensor plate. When a human touches or comes near to the metal sensor plate the capacitance is changed and the circuit turns on.

The sensitivity is adjustable so that at a lower setting it will require you to directly touch the sensor plate. At its most sensitive setting, it will detect your finger through paper, plastic, glass, or even a brick.

The larger the sensor plate the more sensitive the switch. The sensor plate is the triangular circuit board at the front bottom of the lamp.

1-40 of 61Next »
rodriyrex5 years ago
Hello, I have a question. Can I use the QT100A instead of the QT113?
mikey77 (author)  rodriyrex5 years ago

It appears that the qt113 is now only available in quantities of 4000 or more.

As of now, you can still get the qt100 in small quantities. I finally got a chance to try one out and it is as sensitive as the qt113 and works fine. You can get a sot23-6 version here: http://www.saelig.com/IC3/IC3029.htm

jeff-o is right. You will have to add an additional circuit such as a microcontroller or another toggle circuit to keep the lamp on as the qt100 does not latch on and off.
The QT100 would not be a suitable replacement. The QT113 has a "toggle on/off" function, where the output from the QT110 is only active when touched. So, to use the QT100 you'd also need to add something like a flip-flop to toggle the LEDs on and off.
mikey77 (author)  rodriyrex5 years ago
I do not know, I have not been able to try the qt100a. I ordered a couple and they came as a leadless IC about 3mm x 3mm. It is so small, I have so far found it impossible to solder to it.
ohh :s but the QT113 SOIC version it's still available isnt it?
KOTSOS59 months ago

i know this article is old and QT-113 has stopped, but is there any other replacement with so low price?

This is awesome! i've made a switch like this once by accident, it was also touchless, i couldn't figure out what is going on :D thanks for sharing
M0HIZ2 years ago
What a brilliant idea! I might make a modification and try to power it wireless using homemade 'Witricity'.

Thanks for the inspiration!
ripper2.03 years ago
Cool!!! Very nice project
Tomfhowe3 years ago
this just looks so sick
cmarciales4 years ago
Both the QT113 and QT100A are obsolete. But the toggle functionality is available in the AT42QT1012-TSHR, available on DigiKey.com for less than $1, part number AT42QT1012-TSHRCT-ND. Enjoy!
Thanks a lot, I was looking for both and couldn't find them anywhere. The AT42QT1012-TSHR looks also very nice with auto power off. :)
Blue_Flame4 years ago
Many aplogies for my incompetence, but will this work off of a 12V supply? Or, alternatively, be modified to give out 12V? Looking to drive many (56) LED's - using this as its switching circuit.

sporkmasta4 years ago
Looks like an alternative to the IC that this instructable uses:

$2.48 on digikey.... Going to test it out
reecesrcool5 years ago
i must say very nice, and with a big enough imagination (which i have) and funds (which i dont have) this could be used for some sort of home automation. considering you dont actually have to touch the metal to control a relay you could lay thin strips of the sensor plate (or if possible just plane wire?) under your floor to detect where you are in your house and when you leave one room turn off all electronics or atleast a light in that room and turn everything on in the next room. it would be a pretty good energy saver for someone with kids who never remember to turn off their lights.... sorry you're ible just sent my brain into overdrive with ideas
mikey77 - great 'ible from both technical and artistic viewpoints as far as the eyes of this beholder see! Thanks!

reecesrcool - Sorry it's many months before commenting, but just saw this. You have a great idea in theory and I do believe you could make it work. Just a couple of cautions that you may have already considered. Whenever you go to the work of putting something under the floor you want to test it oh so very thoroughly before tearing into the floor. To avoid embarrassing anyone, let's just say I've heard that's the case. Secondly, this actually takes a bit of inventive programming and possibly more hardware than originally planned to come up with the right combination of sensors and a reliable algorithm to tell whether EVERYBODY is out of the room yet before turning off the lights. For example, was that 1 person who entered, or 2 side-by-side? Best of luck if you tackle it.

daniel254 years ago
This is a very elegant and fantastic design. I hope I could also make one out of Printed Circuit Boards.
vya_73914 years ago
excuse me, where can i find the curved circuit board, i've been looking for it but i just can't find it
bull6604 years ago
very very nice. what gave you the idea of making such a magnificent piece of work? if you don't mind me asking.
Copper gets ugly if exposed for a long time, specially if someone is touching it regularly or if someone tries to clean it with something wet. So I'd suggest using some kind of spray coating to avoid that.
nice work..congrats
ap19225 years ago
Hi, Is there any other IC that could be used?, Because I cant seem to find the QT113.
razz19695 years ago
I have seen this circuit incorporated in a table saw once. When you finger or any other piece of your body comes near or touches the blade, the blade retracted at a blink of an eye. The inventor was using hot dogs to simulate human flesh. Every time the hot dog touch the spinning blade the blade stopped and retracted instantly. So fast that you could not see the action, and every time the hot dog came away without a mark.
Yea it was n timewarp on discovery
Taost5 years ago
in that case, would a QT118HA-ISG be a viable replacement, I cant find a qt113 that isnt either out of stock, or that you need to call the company to buy it. http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=427-1139-1-ND thats the link to the ic
zappotek5 years ago
I can't seem to find the IC from a supplier in the UK, and am having trouble finding a replacement. Even the IC you used seems to be obsolete in the states also. Thanks to any who can help :) Very nice instructable by the way, will try and finish it when I can finally get all the parts :P
jam BD zappotek5 years ago
It is very elegant =D As for the IC Qt113. The circuit can be replaced by a 555 timer with the capacitance change changing the frequency and use a band pass filter to detect the change of frequency to turn on the light.
mikey77 (author)  zappotek5 years ago
The Qt113 is not obsolete. I am so sorry that you did not bother to read as far as step 2 where I gave everyone a direct link to where you could buy the QT113. Its true, the Dip version is no longer available, but a SOIC version is available. There are also improved versions of this type of circuit available. While SOIC sized ICs are a little tricky to solder, here is a link to where I have detailed a fairly easy way to solder them: http://www.instructables.com/id/Make-A-Remote-Control-Ring/step4/Picaxe-Microcontroller/
Sin7423 mikey775 years ago
Hello Mikey Excuse me for my english i'm from holland. I wanted to ask you where i can by the touch sensor QT113. And witch one is the best solution for the job? I have searched and found a couple but i dont know if it wil work. Thanks in advance.
I did say 'in the UK' but there you go, the manufacturer's site lists the chip as obsolete. I suppose if this is the only source then I shall have to get it from there. Thanks for the SOIC soldering method by the way, good idea :)
NoPinky5 years ago
Very nice instructable, I would like to make one, but I haven't found this kind of thin copper clad here in europe yet. You said you saw it on ebay, can you please give me a link, or the name of the seller? Thank you!
mikey77 (author)  NoPinky5 years ago
Here is one: http://cgi.ebay.com/24-shts-Copper-Clad-Laminate-FR-4-008-4-5-x-8-DS-/310216528371?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item483a5891f3 If you search ebay for pcb boards or pcb laminates you can find others.
NoPinky mikey775 years ago
Thank you!!!
shadleyhax5 years ago
well done for winning mate. Well deserved. I saw this and was instantly wowed to the point of thinking of applications that I could use it for. this will be my intro to PIC's I think :)
manish635 years ago
Hey really love ur design and want to try it out but just a few questions... 1.could you please include a tip, step or instructions of any kind on how exactly to mount the circuits to the bendable board 2. and another angle shot of the triangular mount to the lamp so we can see how it is done...
mikey77 (author)  manish635 years ago
The circuit board is mounted to the lamp body with two 22 gauge solid wires which are stiff enough to hold it in place when soldered to the front copper traces that go to the LEDs. A third solid insulated wire goes through a hole in the lamp body to the front triangular sensor board. It is longer than necessary to allow adjustment of the sensor plate. You can see the solder joint at the bottom front of the triangular sensor.
lanre5 years ago
Just want to know, do you have to torch the switch to turn off the lamp? Some explanation will be appreciated. Thanks.
mikey77 (author)  lanre5 years ago
If you bring a finger or hand near the lamp it locks it on. If you do it a second time it turns it off. It does not have to be touched.
gloflyer5 years ago
Your design is beautiful and elegant. Almost like jewelry.
MARIUSBMX5 years ago
Awesome work!!!!. I think this is one of the best and creative stuff I've seen :)
1-40 of 61Next »