The tip jar is going electric with DipJar, a new product being tested for coffee shops and other counter service businesses. Here's how it works: the owner of the business sets a specified amount for the DipJar — the folks at Bon Appetit found one at the a location of Oren's Daily Roast in New York City that's set at $1 — and then every time a customer swipes their card, they tip that amount. (So you'd have to swipe twice for $2, etc.)
The system then splits the collected tips among employees based on how long they were at work on any given day. DipJar works with credit cards and debit cards and you can even get a refund for a tip within 30 days. Now, no excuses, just because you're out of change, doesn't mean you're off the hook for tipping.