A far better strategy (more reliable) would be to simply purchase bitcoins and wait until the double, then sell them. Trying to actively trade and buy/sell on lows and highs is almost certain to leave you penniless.

If Bitcoin catches on, it will do much more than double. So just buy $100 and sit on them. You might be suprised how quickly it happens... could be a week, or a month, or a year.  But most investments require 5-10 years to double in price (and that's if you succeed!)