Thanks all, I think a deeper shelf attached with hinges might work, the proper mount looks like the sturdiest solution but this is a mini projector so doesn't have screw holes for a mount (and I'm trying to keep it as close as possible to the ceiling due to low head height).
Thanks, this was helpful because I didn't know my projector had a central hole for mounting - it was hidden by a sticker. I've now ordered something similar to this which I think will work much better than my terrible initial bodge attempt.
Thanks all, I think a deeper shelf attached with hinges might work, the proper mount looks like the sturdiest solution but this is a mini projector so doesn't have screw holes for a mount (and I'm trying to keep it as close as possible to the ceiling due to low head height).