Camera Obscura

I had a great deal of difficulty with this project. I used my guest room which had only one window and once I had the room blacked out was completely dark. The walls were a light color as well. To cover the window I used black contractor garbage bags and taped it over the window, allowing the room to be completely blacked out. For my lens I used a 50mm from my Cannon T3i. I cut a small hole in the middle of the window and placed the lens in the hole, I played around with moving the lens facing inwards and outwards but overall I did not have really any luck. Overall I did not have much success with this project. I do want to attempt this again and would like hear some feedback and recommendations. I feel that I had the room blacked out enough, I had a decent lens to use, the bedroom I used had a light colored wall and was blacked out but I still did not get any sort of image though the lens