Circuit Lake

Electronic Project and Circuit Collection

Weasure, Smart Weight and Dimension Meter

12/22/2011 Category: Measurement, Project, Renesas

Weasure is M16C/62P-based system that can weigh and measure packages for shipment. Simply place the package on it and both the weight and dimensions are instantly displayed on LCD. If user connects the device to a PC’s serial port using RS232, then the data is uploaded directly to the PC, where a shipping application can send the measurements directly to the shipping company’s web site, further streamlining the process.

Smart Weight and Dimension Meter

The project uses modified existing postal scale, DigiWeigh DW-36XP. The measuring component of the scale is a strain gage. This is a metal bar with a flex point (the hole). A resistive material is coated on the bar above and below the hole. As a load is applied, the bar flexes, causing small changes in the resistive characteristics of the bar’s coating. To measure the size of the box, a row of inexpensive photocell light sensors spaced one inch apart is placed along the axis for height, width, and depth. When a box is placed on Weasure, examining which photocells show a “dark” reading determines the size.