I am currently working with a Texas intruments lightcrafter evaluation module and I would like to get the projector and psycopy to display my stimulus at 180hz. I have enabled the FramePacker functuion and if I run scripts with psychopy’s internal frame counter enabled I do get a readout of about 180 fps. Regarding the projector itself, I enabled it to run in monocrome mode with a grayscale depth of 7bits, which gives it an output of 180hz. I varified if the the projector is really displaying psychopy stimuli at 180hz, by running a script that displays a simple gray bar with an opacity of 0.8 and then measured the refresh rate with a photodiode. This is the reading from the photodiode:
The lenght of a single frame appears to be 5.55ms which corresponds to a refresh rate of 180hz.
I also tried this script, which makes a flickering rectangle, which I got from another post:
mywin = visual.Window([912, 1140], fullscr=True, monitor="DLP", units="cm", screen=2, useFBO= True) framePacker = ProjectorFramePacker(mywin) photodiode = visual.Rect(win=mywin, width=10, height=10, pos=[0, 0], lineColor=[1, 1, 1], fillColor = [1, 1, 1]) while True: photodiode.contrast *= -1 photodiode.draw() mywin.flip()
And got this output, it flickers at 180hz it seems.
The last thing I did was to check how many frames it dropped during use. I plotted the graph and got quite the surprise:
From the graph it looks as if it draws one frame really slowly (frame interval = 15ms) and two really quickly (frame interval is less than 2ms).
My question is if I evaluted this correctly, it seems to be running at 180hz but I can’t be sure. I really don’t get the frame inteval plot, why is it doing that, is it normal?
Also is it possible to somehow “trick” the projector to display double the amount of frames, thus raising the frequency to 360hz?