To pay by weight, you need to have a NTEP certified scale. That means that the scale indicator/head needs a certificate, and the load cell / platform also needs a certificate. Once you have the hardware, you are required to calibrate your scale once a year with your state weights and measures commission.
Here are some links to state Weights and Measures Programs:
We have developed a relationship with a company called Rinstrum. They are based out of Australia, but have offices in the US. Their US telephone number is (248) 680-0320. The local sales rep is in Post Falls Idaho. To purchase a Rinstrum scale, please contact them directly, or let us know and we'll put you in direct contact with the local sales rep.
Rinstrum has many solutions that are all compatible with our software including platform scales, pallet scales, hanging scales, etc. If you have your own scales / load cells they can sell you just the scale indicator to make your scale compatible with Harvest Clock.
In particular, we have tested with the Rinstrum R320 Indicator. It's capable of handling almost any load cell with a 4 or 6 wire interface. For blueberries, we use a 14"x16" platform load cell with a Rinstrum R320 indicator.