Cell Phone Interference

[ibrandt]

Hi,

Just wondering if anyone else has issues with cell phones inducing spurious key presses when used in proximity to their TouchStream? I have a Nextel i1000, and if it gets within about 1.5 feet of my LP whilst transmitting things go haywire.

Regards,

Ian

[Patrick Bennett]

Just think... you put that thing next to your skull. :eek:

[ibrandt]

Originally posted by Patrick Bennett
Just think... you put that thing next to your skull. :eek:

Heh, right. Ever noticed the immense drop off in I.Q. the average person suffers when getting one within 1.5 feet of their head? There must be some correlation. ;)

[-jeffB]

I wish FingerWorks were in a position to release more info about the internal construction of these products.

I'm not at all surprised that the keyboard is susceptible to cell-phone interference. Whatever specific technique they're using to detect finger proximity, it has to be detecting pretty small signals, and it's likely (although not guaranteed) that these signals are traveling over wires several inches long. Sounds like a recipe for RF interference to me!

(Hmm... maybe I'll play around this evening with a small loop and an oscilloscope, and see if I can figure out anything about what the KB is doing. :))

I'd also expect that there might be interference from cordless phones, baby monitors, and (maybe) WiFi transmitters. On the other hand, most of these use lower transmit power than cell phones, and they're a bit less likely to be within 1.5 ft of the KB.

Is there anything the FingerWorks folks would care to divulge about all this?

[nomaded]

Originally posted by ibrandt
Hi,

Just wondering if anyone else has issues with cell phones inducing spurious key presses when used in proximity to their TouchStream? I have a Nextel i1000, and if it gets within about 1.5 feet of my LP whilst transmitting things go haywire.

Regards,

Ian

I used to have this problem, quite acutely, in fact, and it was also caused by a Nextel phone (the i90c). I carry 2 cellphones on me, regularly, to work - the work provided i90c, and my own. Before getting the i90c, my TS Stealth had no such problems, but when I got the phone, the keyboard would start spewing extra keystrokes. It was also the beginning of winter, the air was fairly dry, so I was getting a lot of problems with interference from static electricity.

The solution to all of this? I ended up getting a replacement Stealth (or ST as they were called before being discontinued). Apparently, my original Stealth was an old "analog" model. The replacement is a "digital" model that's supposed to deal with static and interference from the i90c a lot better, according to Customer Support. And in my experience, since getting the replacement back around New Year's of 2003, it's all been true. All the problems I had been having have pretty much gone away. I still have some static problems where when I first sit down, the ST would be unresponsive, but a quick flat palm tap usually fixes it. I think the best thing about getting the replacement ST is that now I have the programmer's pad silkscreened on the appropriate keys (tho a couple of them are marked wrong).

Great keyboard. Great technology. Great service. I'm really looking forward to receiving my MacNTouch.