Post by thread:[OT]:Black Liquid

Hello everyone. Ok, I'm wondering if anyone knows of a liquid the darkens color dramatically when it receives electric current. I have this little ideal but I don't know how I could implement it without something to study about it. To tell you the truth I'm thinking about making a window that can be triggered to change from transparent to opaque so no one can see in. Darvell aka Epox spam_OUTspowell5TakeThisOuTneo.rr.com UltraDev Studios Worldwide -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

hmmmm.. didn't really give that much though. Can a LCD become 100% clear, I mean clear as a regular piece of glass? ----- Original Message ----- From: "Dipperstein, Michael" <.....mdippersKILLspam@spam@HARRIS.COM> To: <PICLISTKILLspamMITVMA.MIT.EDU> Sent: Tuesday, July 16, 2002 4:12 PM Subject: Re: [OT]:Black Liquid > What if the window is a giant LCD? Then you can make it opaque or transparent > one pixel at a time. > > -Mike > > {Original Message removed}

The way this typically would work is with the nematic crystal (the same stuff in LCDs) and a polarizing filter. You can use an electric current to polarize the crystal in line with the fixed filter to pass light or 90 degrees to block light. Search for Electrochromic Window, switchable glazing, and/or smart windows. Al Williams AWC * Floating point A/D http://www.al-williams.com/awce/pak9.htm > {Original Message removed}

Not 100%. It'll depend on the setup. One thing to keep in mind is that there are different types of liquid crystal material. I believe all of them are temperature sensitive and one of the reasons we don't see widespread usage of electronically darkened windows is because of this temperature sensitivity. I'm curious to know what resources there are out there for hobbyists to make or purchase their own LC material. A large pane of glass with LC material would be very expensive. Window panes with LC in between and computer screen polarizing filter(s) on either side would be very inexpensive to build if the LC isn't too expensive. It would be very low quality (especially trying to put transparent elextrodes on the glass) but it would be good for experimentation. -Adam Epox wrote: {Quote hidden}>hmmmm.. didn't really give that much though. Can a LCD become 100% clear, I >mean clear as a regular piece of glass? >----- Original Message ----- >From: "Dipperstein, Michael" <.....mdippersKILLspam.....HARRIS.COM> >To: <EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU> >Sent: Tuesday, July 16, 2002 4:12 PM >Subject: Re: [OT]:Black Liquid > > > > >>What if the window is a giant LCD? Then you can make it opaque or >> >> >transparent > > >>one pixel at a time. >> >>-Mike >> >>{Original Message removed}

There was an article on using large surplus laptop LCD panels like this in (?) Nuts & Volts recently. Basically, you strip off all the driver connections (usually flexi-print) , and connect all electrodes on each of the 2 glass sheets with silver paint or conductive epoxy, and apply a squarewave across these 2 electrodes to switch from dark to light, or vice versa, depending on panel type. Would make a neat 'switchable' window if you used several panels - if you got enough panels maybe you could build a decorative low-res matrix display on your wall - one panel per pixel.... now that would be REAL cool!!!!!! On Tue, 16 Jul 2002 15:56:28 -0400, you wrote: {Quote hidden}>Hello everyone. Ok, I'm wondering if anyone knows of a liquid the darkens >color dramatically when it receives electric current. I have this little >ideal but I don't know how I could implement it without something to study >about it. To tell you the truth I'm thinking about making a window that can >be triggered to change from transparent to opaque so no one can see in. > > >Darvell aka Epox >spowell5spam_OUTneo.rr.com >UltraDev Studios Worldwide -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

>hmmmm.. didn't really give that much though. Can a LCD >become 100% clear, I mean clear as a regular piece of glass? Yes, there used to be LCD panels available which were designed for desk type digital clocks, and had all the connections on one edge. It was possible to mount these with just the connector edge in the "works" and the other three edges of the glass in free air. These displays were clear when powered off, and the operated segments looked like aluminium metallisation (silvery) when turned on. The only disadvantage from your point of view would be that the metallization layers inside are faintly visible, but if your window was done as a large single segment this would not be a problem. Would have some horrendous capacitance to drive though :) -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

On Tue, 16 Jul 2002, Epox wrote: >Hello everyone. Ok, I'm wondering if anyone knows of a liquid the darkens >color dramatically when it receives electric current. I have this little >ideal but I don't know how I could implement it without something to study >about it. To tell you the truth I'm thinking about making a window that can >be triggered to change from transparent to opaque so no one can see in. Try the lava lamp principle. In this case a small pump blows particles into a liquid and keeps them agitated. When you turn off the pump the heavy particles fall down slowly. Peter -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.