Touch Lamp Technology

[km-r]

i have these schematic of a 3step touch lamp dimmer in a magazine...
as well as a touch-sense switch. its plainly an oscillator and a detector...

[SISKO]

A couple of touch circuits http://www.talkingelectronics.com/te_interactive_index.html ---> GoTo touch circuits

[nelson]

Piezo switches.......

[Paul Marossy]

Capacitive touch doesn't necessarily require you to touch it with your bare flesh... just look at an iPod wheel!

Yeah, but try turning on a touch lamp with gloves on. It won't. 

The iPod wheel is a different technology, and it's akin to the controls on a laptop computer.

[studiostud]

Just get some flesh and glue it to the bottom of your shoe 

It rubs the lotion on its skin or else it gets the hose again.

[space_ryerson]

Is the noise due to the PWM signal?

It depends on the technology being used. In the case of the lamp its the line AC. There are a number of way to sense a body presence. I think somewhere I have a post where I cover the more popular ones. AFAIK no touch sensing technique uses PWM. Many do use a clock source of some sort. Most of the "theremin" circuits use the body's capacitance to alter the frequency of the clock. This can be very tricky which I also discuss in some previous posts and why I don't like this system.

Andrew

I'll do a search and check it out. The only reason I asked about PWM is that it is mentioned in the first link I posted, although honestly, I still have a lot to learn about capacitive touch.

Capacitive touch doesn't necessarily require you to touch it with your bare flesh... just look at an iPod wheel!

Yeah, but try turning on a touch lamp with gloves on. It won't. 

The iPod wheel is a different technology, and it's akin to the controls on a laptop computer.

I agree about the touch lamp. It is different, but I have seen simple capacitive touch circuits work through plastic, which is promising enough for me to want to try to implement it somehow.

The iPod wheel is actually somewhat simpler than a trackpad on a laptop. Check out this link. Pretty neat, right?

On a tangent, I have taken apart a fair amount of cell phones/blackberries/etc. at work, and it looks like the keypads might work via capacitive touch, not mechanical switches. Am I wrong?

Have any of you had a look at the Stribe project?

[The Tone God]

The ipod wheel uses a "burst" system to sense the touch and a gradient pattern on the board to derive the location of the touch on the wheel. Overkill for this application.

Oh and those QTouch ICs AFAIK are no longer availible in DIP packages.

Andrew

[Taylor]

The ipod wheel uses a "burst" system

Oh no... I think I know what's about to happen...

[WLS]

Just get some flesh and glue it to the bottom of your shoe 

It rubs the lotion on its skin or else it gets the hose again.

Just use some Zip-Ups Shoes from the eighties and leave the soles off. For thoughs that never heard of them Zip-Ups Shoes where shoes that the uppers were interchangeable by zipping an upper to the sole.

BIG BUST!!! 

Bill

[Paul Marossy]

I agree about the touch lamp. It is different, but I have seen simple capacitive touch circuits work through plastic, which is promising enough for me to want to try to implement it somehow.

The iPod wheel is actually somewhat simpler than a trackpad on a laptop. Check out this link. Pretty neat, right?

On a tangent, I have taken apart a fair amount of cell phones/blackberries/etc. at work, and it looks like the keypads might work via capacitive touch, not mechanical switches. Am I wrong?

Have any of you had a look at the Stribe project?

Huh, interesting. I guess the plastic must be a conductive type...

Just use some Zip-Ups Shoes from the eighties and leave the soles off. For thoughs that never heard of them Zip-Ups Shoes where shoes that the uppers were interchangeable by zipping an upper to the sole.

BIG BUST!!! 

Bill

I was in high school in the early 80s, but I don't remember those shoes at all. 

[WLS]

I was a Bundie in the eighties and my first job out of college was managing a Pic-Way Shoe Mart. I applogise cause I got the name wrong, they where called Change-Ups. After the ability to change the uppers. Anyways the CEO's son came up with this non-brilliant idea. They had china make them and wasted a lot of time and money promoting a product that just did not fly.


Bill