Interesting turnout control and panel sensor switches

[cteno4]

Looks like a fairly new group that has an interesting system for doing cap discharge, and other electrical control for most of the spectrum of turnouts out there. their lighted sensor switches can sense your touch thru a piece of paper and or glass so you can make nice smooth glass faced control panels for your layout.

 

http://www.berretthillshop.com

 

http://www.berretthillshop.com/store/products/bipolar-2-wire-snap-action-base/

 

http://www.berretthillshop.com/store/products/touch-triggers/

 

the price does add up quickly with the parts, but if you want more of a quick turn key solution where you get nice lighted sensors on a star trek control board they do look nice! just screw the wires and draw up your control panel underlay.

 

annoying presenter but shows the basics

 

 

prices 

[kvp]

I checked the system and it looks like they have 5V TTL level touch sensors and standard turnout controls using TTL inputs. Nice and clean solution and it's possible to make a Tomix TCS adapter for using the track sensors as touch triggers (momentary on) or two as touch switches (toggle on-off).

 

If someone prefers mechanical switches, then a few resistors (one pull up, one series, switch wired for pull down, leds driven from output) should allow using mechanical switches instead of the capacitive ones but still use the turnout drivers and interfaces like the DCC adapter.

 

ps: My best guess from the interface description is that they use a small capacitive sensor (like a 8 pin pic mcu) and also drive the two led outputs from the read back output level. IO is 5V TTL in Arduino sensor shield format. Nice idea and could be used for home automation too.

[kvp]

More info how the capacitive magic is done:

http://www.bytecraft.com/Touch_Sensitive_Switch

[cteno4]

I used a system maybe 7-8 years back that was a was capacive discharge when an exhibit client wanted to have some control elements on a large silk screened glass panel. Drilling holes was out! At the time there was a system pretty much like these guys with I think with 5 switchs to relays. They were handmade very limited market stuff and over $1000 for the system! Most expensive 3 buttons I've ever installed, but worked great. One touch screen company was willing to come out and mount surface wave acoustic transducers and receivers on the big hunk of glass then would have needed a custom pic programmed or use a small pc to compute touch points at $5k! But cost on all this stuff has plummeted over the last decade.

 

Jeff

[kvp]

Considering the smallest pic which can handle a single button is exactly 10 years old and costs around 0.6 usd, this technology has been around for some time. Capacitive touch buttons for door entry systems are being made since the 1980ies. Only multitouch screens are a relatively new product, but they use a slightly different and more complex method.

 

Personally i dont like touch buttons as they lack physical feedback and hard to use without looking at the control surface. But they are surely popular. The technology behind them is very simple however. In this case 4 resistors, one or two leds and a small mcu is all what is needed. (2 pins for power, 2 pins for capacitive touch with one as analog in, 2 pins for bus io, 2 pins for the leds)

 

ps: if anyone is interested i can draw a full circuit, but getting the off the shelf buttons is imho better costwise