How do touch lamps work?

SteveSkid

unread,

Mar 22, 1995, 5:48:01 PM3/22/95

to

I have a touch lamp in my bedroom that turns on at the spookiest of times.
Can someone fill me in on how these things work and how I may prevent its
untimely operation.

Thanks
Steve Skidmore
Stev...@aol.com

David Kramer

unread,

Mar 23, 1995, 9:29:00 PM3/23/95

to

In <3kq9f1$n...@newsbf02.news.aol.com> stev...@aol.com (SteveSkid)
writes:

Touch lamps, and other touch switches like on elevators etc, work by
looking for a 60HZ signal. What happens is that all electonic devices
emit some electronic interference. The switch is a 60HZ receiver with
no antenna. When you touch it, or anything large enough and conductive
touches it, the receiver can now pick up a strong enough signal to cross
some level that tells the switch to turn on the lamp.

If you're really interested I think I have a schematic for one. E-mail
me a fax number.
--

DDDD David Kramer
DK KD dkr...@ix.netcom.com
DKK D 72310...@compuserve.com
DK KD
DDDD "I keep pressing the ESCape key, but I'm still here!"

John Lundgren

unread,

Mar 23, 1995, 9:48:43 PM3/23/95

to

SteveSkid (stev...@aol.com) wrote:
: I have a touch lamp in my bedroom that turns on at the spookiest of times.

: Thanks
: Steve Skidmore
: Stev...@aol.com

You might have a local CBer or radio station that sets it off
occasionally. Or the local electrical equipment could be producing EM
interference that's triggering it.

A filter in the incoming AC line could help, or if the problem is CB or
other transmitting equipment, then getting the dimmer RF proofed by the
local ham might be possible.

Adrian Jansen

unread,

Mar 24, 1995, 12:23:45 AM3/24/95

to

Touch lamps work on a high impedance input, expecting to pick up a
hum field or electrostatic DC field from your hand, so any excessive
hum field from leakage around the contact point, or ESD will set
them off.

I made lots using a Siemens S566 chip years ago, but found theyre
more nuisance than worth it, especially for a bed lamp - throw it
out and go back to conventional switch - st least its reliable !

In article <3kq9f1$n...@newsbf02.news.aol.com>, SteveSkid

--
Regards,

Adrian Jansen aja...@adelaide.DIALix.oz.au
Design Engineer J & K Micro Systems
PH (08) 271 4126
Microcomputer solutions for industrial control

Ralph Landry

unread,

Mar 25, 1995, 9:00:49 AM3/25/95

to

SteveSkid (stev...@aol.com) wrote:
: I have a touch lamp in my bedroom that turns on at the spookiest of times.

: Thanks
: Steve Skidmore
: Stev...@aol.com
Steve I also had the same problem and it was a CB'er driving by my house
on a daily basis. I have a small amp plugged into the PC and I can hear
him BS`en and bingo the lamp would go on. I used a clamp on ferrite bead
around the 120v line and have never had the lamp come on in the last 2 months
since putting the filter on. Only when I touch the lamp does it go on/off.
Yet I still hear that CB`er go by the house.

--
Ralph Landry rla...@medar.com

Ted Timmons

unread,

Mar 27, 1995, 12:18:39 AM3/27/95

to

> Can someone fill me in on how these things work and how I may prevent its
>untimely operation.

: Touch lamps, and other touch switches like on elevators etc, work by

: looking for a 60HZ signal. What happens is that all electonic devices
: emit some electronic interference. The switch is a 60HZ receiver with
: no antenna. When you touch it, or anything large enough and conductive
: touches it, the receiver can now pick up a strong enough signal to cross
: some level that tells the switch to turn on the lamp.

: If you're really interested I think I have a schematic for one. E-mail
: me a fax number.

Yeah, if you don't have a schematic, I have one that operates off of a
555. A more simple explanation for the lamp simply turning on is power
fluxes - if you unplug and plug the lamp back in quickly, it will often
turn on. Power outages are fun at my house ;)

E-mail to ted...@teleport.com
--
-=TED=-
ted...@teleport.com Not affiliated with Teleport

Andrew Hana

unread,

Mar 29, 1995, 3:00:00 AM3/29/95

to

SteveSkid (stev...@aol.com) wrote:
: I have a touch lamp in my bedroom that turns on at the spookiest of times.

: Thanks
: Steve Skidmore
: Stev...@aol.com

I have built a very successfull touch sensitive dimmer switch for my
bedside table lamp. It is based on the SLB0586A from Siemens.

I have found the design to be very reliable. However, one does have to
be careful with the senor lead. All the electronics for the dimmer is
built on VERO and is housed in a plastic box under the bedside table.
The inner core of a long piece of coax is connected to the sensor input
on the VERO and the outer shielding is connected to a ground point on the
VERO. The coax leaves the box and is routed to a suitable point on the
bedside table. I have made a small sensor plate from aluminium foil to which
the inner core of the coax is connected.

It is all very neat, and no cables can be seen. It is also very reliable and
the light does not come on without the aluminium sensor plate being touched.

Andrew