Not getting DLP-Link to work - Page 1
Forum section: electronics / projects

author: HeartOfGermany
author_rank: Newbie
timestamp: December 12, 2018, 10:30:42 pm
content: Hello,I am trying to let 3D Glasses with DLP Link react to a bright led flash that is triggered by the VGA Vsync signal. It pulses as intended. The strange thing is, it does not shutter, even when getting close. I tried different Vsync frequencies (60hz, 100hz and 120hz). Last of the 2 should definitely do the trick, since the frequency is officially supported. To verify the signal I hooked up a wide range speaker. It definitely works putting out nice squares as intendet (tested in simulation). My mobile camera proofes the signal is correct, since the brightnes also hard cuts off. (Using exposure timing to verify frequency and waveform)Hm.... So now I do not know what should work. The manual states, that some 50/60hz lights will false trigger the glasses, so it should actually not be toooo picky about the signal. Tested on my 4W chinese LED which also flickers at 100hz (50hz 230V in germany) it also does not darken the "lenses".Since I cannot find ANY information on how this works, I have no clue what to do. I definitely need the glasses to shutter at the Vsync frequency.But what timing does the white flash need to have? If I am not wrong, the Vsync pulse is 64us long. This seems like a nice short, bright flash. What is possibly wrong with this technology? o.O

author: HeartOfGermany
author_rank: Newbie
timestamp: December 15, 2018, 12:20:13 am
content: Ok, other way...I want to switch the LCD of the shutter glasses. At 5V DC it is completely black, but 800hz and als 150hz 50/50 square wave at 5 or 10 or even 12V (all AC, Vp-p)only leave it half "closed". Even more strange. I removed the output resistor and went straight in with capacitors. 1nF. Nothing... 10nF. Still nothing. Now strange! 100nF (or even 11uf!) added to the circuit (while running) results in darkening of the LCD. When removing the capacitor it gets brighter. Than add the cap back it gets darker again. Now randomly, when removing the capacitor, it becomes darker! WHAAAT? How that? Reducing the current carrying capability randomly either results in brighter OR darker LCD? Please explain if you can...BTW: The LCD isapproximatelya 2x5cm square. I don't know, what to do. I want to quickly and relianly change the display to either 100% bright or 100% dark... I don't get it.

author: HeartOfGermany
author_rank: Newbie
timestamp: January 02, 2019, 01:18:52 am
content: Will push this again... Enought people on this forum. Someone needs to be able to know something.

author: ruffy91
author_rank: Regular Contributor
timestamp: January 02, 2019, 08:23:24 am
content: "Because the TSOP75D25 and TSOP35D25 operate at a carrier frequency of 25 kHz with a signal pattern featuring a minimum burst length of 6 cycles, a very high signal to noise ratio is achieved."http://www.vishay.com/company/press/releases/2010/100802optoreceivers/

author: HeartOfGermany
author_rank: Newbie
timestamp: January 02, 2019, 11:23:25 am
content: Well I don't have the IR version though.I am getting some sort of synchronization working with my VGA signal processing. There is a Red, blue and green LED on it, reacting to the Signal. Blue is 1/2 of Vsync pulse. Green is Vsync. The red is... I forgot. It actually does not create that much light though.It seems it reacts to blue/green pulses somehow. My theory is: It is for projectors, where the light comes in a specific order. On an LCD it is all colors at the same time. I guess that is the problem. These glasses are not meant for LCD DLP. Guess I found the problem.Bluetooth and IR also is no option, since I am not able to send the specific signal. I don't know the signal. So that means, I will change the setup to a wired 3D-Glasses and make a circuit that is unfortunately a bit more complicated, but should do the trick.