Adjusting tt speed on the cheap:any tricks?

I have a Michell table with HR power supply which has speed adjusting screw on its back.I don't want to spend $100-150 to buy a strobe disc with a strobe light so i'm trying to adjust speed on the cheap.I did some adjusting using a camcorder with a built in stop watch and counted if the table did 33 1/2 turns in a minute.Any other ways to save a buck?Thanks in advance.
The stop watch works well, but average it over 3 to 5 minutes for better accuracy.
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If you want something a little more 'scientific' get the Cardas LP which is great for set up and break-in and also has a device for setting speed with a regular lightbulb. You should have this LP anyway, the speed control is just a bonus.
you can get a free strobe disc here:

No Stobe light is needed, simply use it under a normal incandescant lamp (60hz - use the corresponding disc)