MAKE: PROJECTS Eccentric Cubicle Figure 09.27: I am unabashedly enthusiastic about the glories of simple, linkage-based mechanisms. receiver on the (still undetermined) base, I drilled and tapped three ¼-20 holes, with an additional ¼" hole dead center to run the air pump power cord through. Worked like a champ, looked like something from Professor Zork's lab. [Figure 09.26] Thoroughly splendid. Air Supply 3 I wanted a pair of reciprocating bellows for the air supply sub- assembly, which meant fabricating a mechanism to convert rotary motion to vertical reciprocation. The drive motor I 3 No, not that insipid band from Australia. used was a 6 RPM animatronic gear motor pulled from an animated Christmas lawn ornament, where it had previously seen duty making Vacuum Molded Santa's arm wave cheerily to passing carolers. The two figures show you the actual motions involved in the mechanism and detail the measurements I used to get the mechanism turning over at a smooth, relentless and mathematically satisfying rate. [Figure 09.27, Figure 09.28] Having massaged the measurements to an apparently functional point, I prototyped the movement to test the results, using aluminum flatbar and 3 / 8 " square steel box channel "reclaimed" by disassembling one of those articu- lated arm desk lamps (a common dumpster commodity and excellent source of useful raw material). 266