On Wed, 4 Feb 1998 21:38:49 -0500 Frank Mckenney writes: >I'm working on my first PIC project, an X-10 data logger based on the >16F84. Since I'm not in a position to design or etch my own circuit >boards, I went looking for pre-designed boards on the 'web. You don't need an etched circuit board to make a small PIC circuit work. Nearly all of my prototypes are on perforated board (available at Radio Shack at astronomical markup). It's low cost, infinitely rewirable, and usually has room for last-minute changes. Good soldering skill is required. If you don't have it, you ought to learn sometime anyway. Here are some general practices. - Use good IC sockets. The plastic ones with dual leaf contacts are fine. There should be metal on both sides of where the pin would go looking into the holes from the top. Stay away from plastic ones with just a simple single spring contact, they fall apart. Machined-pin ones (gold, of course) can be used if there's a big surplus in the budget. There isn't much advantage to them for general hacker work. - Glue the socket that will contain the PIC to the board. I use hot-melt glue. This saves stress on the wiring when the PIC is repeatedly removed for programming and reinserted. - Put a 0.1 or 0.22 uF bypass capacitor at the top or the bottom end of the PIC, and run its leads directly to the Vdd and Vss pins. Of course when using larger PICs that have multiple Vdd and/or Vss pins, connect them all together. Wire ground and power to all the ICs using #24 bare copper wire before installing any other wiring. Put capacitors near the other ICs as needed (Sequential circuits, like shift registers, memory chips, counters, etc. definitely should have them). - Put the crystal and its capacitors right next to the PIC. The wires need to be short and direct. The midpoint of the 2 capacitors can be connected either to Vdd or GND. - Use wire-wrap wire for the signal wires. Cut it to length, and strip 1/8" off of each end. Bend a hook in the end and wrap it tightly around the pin, then solder. This takes some practice. A medium sized pair of "forcepts" or "hemostats" or whetever the doctors that use them call them, is very good for bending the wire. Circuits made this way can be the same size or smaller than printed ones (of course, not if SMT parts were to be used) and quite durable. It only takes a couple of hours, and no special materials, to make a one-of-a-kind circuit with 3 or 4 chips. _____________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com Or call Juno at (800) 654-JUNO [654-5866]