The Yard-Stick is a tool for the landscape planner, landscape gardener, builder, architect, accident investigation professional or anyone that needs to measure and record the outline of an irregular area. The device combines the familiar rolling wheel measuring instrument with an accurate digital compass, internal memory, display, processor and RS-232 interface. The resulting tool can measure and record the outline of multiple areas, measure distances and direction between these areas and then transfer this information to a PC for displays and calculations. The landscaper or home gardener can use this information to plan the landscaping of a new area or record the landscaping of an existing area. Areas can be displayed and the amount of fill required for each area can be quickly calculated. An accident investigator can measure and record the distance and direction between significant points at an accident investigation scene. This information can then be used to produce both graphical and textual description of the scene. This data can be overlaid on photographic information to produce a complete record of the accident. Paving companies can use the device to measure driveways or parking lots to estimate the amount of material required and to price the work to the customer. The graphical output gives the bid additional credibility and provides the company with the security that the bids are accurate.

The Yard-Stick is built around the Philips 87LPC764 20 pin microprocessor. It uses a Vector 2X compass module to sense direction and a 2 line by 16-character LCD display to interact with the operator. Memory is 8K bytes of I²C EEPROM and the interface to a PC is through a Maxim MAX202 level converter chip. Operating modes are selected by a single front panel switch and single letter commands from a PC. Software occupies the entire 4K ROM space of the microprocessor and provides the real time operation of the unit, the transfer of data to a PC as well as a number of diagnostic modes that can be activated through the PC interface. The rolling wheel is designed to produce a measurement every 6 inches which allows the unit to record up to 2048 feet. The unit allows the operator to select "sections" for recording so multiple areas can be measured and stored. Data is transferred in a text format to the PC that makes it compatible with a number of software packages that can display or calculate area or volumes from this data. The unit is battery powered with low power devices used throughout to provide many hours of operation from standard AA cells.

Microprocessors have changed many things in our life to make them easier or better. The 51LPC steps into the garden and converts a familiar tool into a much more useful and powerful device. The implementation of the Yard-Stick was fun and easy and its operation is even more fun and easy. It’s a tool that’s going somewhere and it’s smart enough to tell you where its been.