We [Rob + Janet + Zach] walked up the hill behind 21 Western Cove on Monday morning to pay campus a visit prior to driving inland to the Haystack winter office. As we reminisced about times spent in workshops past, the bell tower stood as a silent reminder of breaking bread with colleagues and friends.
above, the Haystack bell tower as seen from the Flag Deck.
The tower, designed by George Greenamyer in the late 1960s, is an iconic fixture at Haystack used to pry the community away from their respective work and into the cafeteria. Its sound represents the arrival of culinary delight and good conversation. We decided to build a representative and functional model of the tower for the winter office. Before leaving campus that day, our group recorded several audio clips of the ringing bell, taken from the cafeteria deck, the long stairs down to the flag deck, and the boardwalk outside the jewelry studio.
above, the finished Haystack Winter Meal Annunciator (henceforth H.W.M.A.), basking in the Friday evening light of the winter Fab Lab. Note binder clips, which are used to temporarily clamp reinforcement strips during glue-up, a last-minute addition to reduce buckling during activation.
above, a video clip of the Haystack Winter Meal Annunciator in action. Make sure to turn your sound on to hear the tiny click of the microswitch, the ringing bell, and the ensuing delight from across the lab.
The H.W.M.A. is mostly constructed from two types of parts: thin chipboard panels and white plastic clips that hold the panels together, which I call Clip-Os. The panels were laser cut out of 1/32” stock and have a 5x5 mm cutout 10 mm from an edge to connect to adjacent panels. Clip-Os, which were developed while at Haystack for this project, are 3D printed out of PLA filament and include a flexural locking tab which reversibly secures the panels during assembly. Prior to designing the complete tower model, I tested the concept with a simple button box that Tina, one of the Creative Makers, helped assemble during the Tuesday afternoon session.
above, the 5-button box, assembled during the second Creative Makers session, was used to control Rob’s laptop which hosted trigger-able student recordings. It used ten 90-degree Clip-Os and a few bits of chipboard to test the Clip-O concept.
A “standard” Clip-O, if there could be such a thing, has a 90 degree included angle and accepts identical 1/32” stock, chipboard or otherwise, from each open end. The tabs are oriented on the outside, so disassembly is simple even if the parts are used to build a fully enclosed box. The ends of the chipboard are offset, which leaves a gap at the corners that reveals the inner workings of the structure.
above, a render of a “90-degree Clip-O” snapping onto a waiting test 1/32” test coupon.
The H.W.M.A. required many weird Clip-Os due to its various corner angles, along with the other parts I wanted to integrate into the Clip-Os. For example, it was important that the speaker itself live near the bell, so I placed it in the iconic sloped roof and supported it using a modified offset Clip-O I had previously designed to hold the roof panels in place.
above, a “180-degree-wobble-speaker Clip-O”, used to hide the speaker in the roof of the H.W.M.A.
Another roof Clip-O included a press-fit mounting slot for a snap-action switch along with a flexural spring, which provided the return force for the lightweight plastic bell.
above and below, a “180-degree-switch-flexure Clip-O”, which connects to the H.W.M.A. actuation string and tells the audio board to play back a bell recording.
In total, the H.W.M.A. required 38 Clip-Os spanning 11 variants:
| Clip-O | quantity | notes |
|---|---|---|
| 45-degree | 1 | top of roof |
| 90-degree | 12 | “standard” |
| 90-degree-chonk | 4 | connects tower to 3 mm plywood base |
| 90-degree-chonk-signpost | 1 | holds sign, mounts to base |
| 92.39-degree | 4 | for bevel below bell housing |
| 135-degree-jog-rope | 1 | back of roof, hole and guide for rope |
| 168.23-degree | 8 | above and below bevel, below bell housing |
| 180-degree-switch-flexure | 1 | roof support, holds switch and return flexure |
| 180-degree-wobble | 1 | roof support, wobble to center roof |
| 180-degree-wobble-speaker | 1 | roof support, holds speaker |
| stubbyleg | 4 | legs for base, single sided |
I used a single-ended Clip-O in the Onshape model that I copied into each new Clip-O design, which kept the model relatively clean and made deploying fresh Clip-Os quite fast. If you have Onshape and the model still exists in the CAD cloud ether, you can visit the original Clip-O design files here.