AVR-Chat

About 20 years ago I help a young guy design a Hot Tub controller.

At the tub was an LCD display and a few buttons that show the user what was going on, at the equipment room (high voltage) were pumps, heaters, blowers, relays for lights.

The guy wanted to use two 68hc05 controllers, one at the tub end and one at the high voltage room.

The two schematics were laying side-by-side on the table with a connector on each page with the same signal names.

I asked if the two chips were side-by-side on the PCB.

He proudly says, "there will be 200 feet of wire between them."


Same problems, same solution.

Two micro controllers with a rs-485 chip between them.

Each chip talks to the other chip via their async serial ports,
the same way you talk to a PC.

An rs-485 chip can drive 1000 feet of cable, and properly terminated can withstand a low voltage lighting hit.

A 18-pin PIC on the LED end and what ever you want on the controlling end.

Simple call-and-response system will give you more then enough communication to light up a few LEDs.

After you do this for the first time, you will have a library of functions to use again and again.

Robust and simple, cheaper then you think.

After you replace a few processor boards, the cost of doing a real design is better then fixing an on-going problem.

don