The website will have 1) His history/ current situation/ goal. 2) A set monetary goal and its uses - and an online counter. 3)Donation page and download of free content (art by him or coupons from near by establishments. What would move you to support and donate? An awesome website? A great video? Really fun perks?
Fun perks? Hell no!
Most people don't give because there's no assurance that money will be used properly. It may simply be feeding a habit or going down a bottomless pit.
If a homeless person were raising money not for himself directly but for a reputable charity, then that might motivate contributions. So if the QR code led to a local charity website – one that gives him a place to stay, rehab resources (if needed), counseling, job placement, etc., then someone like me would be much more likely to give.
Where I'm located at the moment, 2 or 3 homeless people per day approach me asking for money. Without assurance that the money would be used to help that person, I don't give. If he held out a QR code that took me to the local charity that's helping him out, that would be entirely different.
He'd become a nonprofit fundraiser rather than a beggar.
And that's a crucial difference – not only for getting results (i.e. money) but also for his self-respect.
Holding out an empty hand = begging.
Holding out a QR code as a fundraiser = employment.