Most people who use Bristol Pounds (£B) pay using the TXT2PAY system. This is where the customer sends an SMS to the £B people that reads
pay <pin> <business_to_pay> <amount>
E.g. in the video, the txt reads
pay 1234 watershedtratest1 12.60
The £B people then send an SMS to the business’ phone to confirm payment – that’s the only way a business can tell if a customer really has paid them.
We have a few problems with this workflow:
- Our bar is quite big: only having one phone to receive payments will be troublesome
- Phones can break easily, and our bar is a very unfriendly environment for any technology
- Phones are easily stolen, and it’s inconvenient to lock one down because ideally it would be moved up and down the bar to wherever the transaction was taking place
- SMS messages can, on occasion, take a while to arrive
- An SMS message can be faked trivially, so a confirmation SMS is no guarantee that payment has actually been made
So, we decided to create till displays that show payments made, with data driven entirely by accessing the APIs of £B servers. The workflow here is that when a customer has sent a payment SMS, the cafe/bar staff serving the customer hits “refresh” on the till display, and the display then shows any new payments on-screen.
I’ll write some more details about how this will work later on, but for now, here’s a video showing our first working prototype.
At the moment, this is no more than a glorified/secure/rugged mobile phone: there’s no integration with the tills as such. At some point, when we have new till systems in place, it would be nice to learn how to talk to them, and so integrate payments properly.