Over the weekend I met the incredible Maurice Blackburn. He is a weaver that has built 2 looms from scratch. He then built a computer controlled system for one of them using an Arduino. He wrote and article on it that appeared in the Oct 2012 Complex Weavers Journal.
I ran into a snag on my loom build. I have it set up for 16 shafts, but it is only 22" wide and that doesn't leave me enough room for more than about 12 treadles. Adding an electronic dobby will solve this dilema for me! I plan on building one for my loom the winter.
You could build or buy a mechanical dobby system, one with bars and pegs, or you could build or buy a computer-assisted module. However, the term "compu-dobby" has been trademarked by AVL Looms so the only actual compu-dobby is one of the models manufactured by AVL. I think there are 4 different models now. Besides using bars and pegs, there is another mechanical dobby that uses heavy paper or plastic with holes. Cyrefco used to make these in California to fit Scandinavian style looms. I have seen looms with plastic sheets in Vaxbo, Sweden, weaving table linens. Any of these styles of dobby loom can have one or two treadles.
I'm sorry for stepping on a sensitive naming issue. I end to refer to cola flavored drinks as "Coke" and facial tissues as "Kleenex" as well. I ment no offense or trademark infringement and have edited the post.
You could build either kind of dobby. (I just happen to know that compu-dobby is registered by AVL and they can be sensitive on this issue; I don't work for them but I own 3 of their looms and have taught at their factory-classroom in Chico, CA.)
A 16-shaft loom of this width could work with levers, as a table loom, but of course it slows your progress on the cloth. Even if you had space for 18 treadles, that can be a severe restriction when there are more than 2000 combinations available. Making or buying a dobby head of either kind would be great!
I got nearly finished on a dobby controller last summer, but final year and work stopped the project in it's tracks.
I used servo motors with a dedicated servo control board. They don't get heated up like solenoids, they're also easier to bvuy as a normal consumer on ebay or whatever. On top of that, servo projects are very common in the hobbyist RC car/Robot builder community so there's a wealth of information on how to use them.
I have also been considering a countermarche style system whereby the shafts are at rest in the centre of the shed and a circular chain with both a lifting and lowering bar attached raise and lower the shafts.
Each shaft would be having a flat steel bar protuding from it's lower portion, with a doublefaced hook on it, which can be pushed or pulled to one side or the other. In this way the raising shafts can be balanced against the lowering shafts and you eliminate problems associated with having to lift all shafts against the pull of gravity, and can do away with systems of leverage or large scale mechanism.
I have woven on looms using a system similar to the one I described and i feel they are vastly superior in both mechanical simplicity and ease of use to the top or side loading dobby which lifts all shafts from a lowered position
Maurice has passed on. I am _not_ a weaver, but a computer engineer. Have been asked to help confirm his loom still functions--and get it back into use with other loving hands of one of his friends... The loom has pins (screws) on the 12 shafts, that catch when solenoids thrust into the path, controlled by a custom circuit around an Arduino Mega, connected to a Windows PC. It seems the Arduino just sits in a loop that interprets a serial feed into the shaft pattern to activate. The pattern seems to come from a Windows program PixeLoom on the PC. It should send a pattern, then wait for the treadle acknowledgement back to trigger sending the next pattern. We can "see" the Arduino on Com5. We can re-load the Arduino sketch (program)....during which we see the TX/RX flash on the board. We can move the treadle on the loom, which triggers a LED flash on the board, and shows up in the Serial Monitor of the Arduino on the PC. But never seem to get connection from the PixeLoom software....nothing shows in the Serial Monitor, so no Arduino triggering of the solenoids. My next thought is to re-load a mod of the Arduino to include a "BIOS Self Test" sequenced strobing of the solenoid shafts at startup. I have sent a "Contact Us" form submission on the PixeLoom website. But the site doesn't seem to be complete/maintained... So not sure if/when we'll get a response. Your thoughts? Many thanks in advance.
Also, the way weaving software works is that you develop your pattern in the software (I use Weavepoint). You set the options of your software to communicate with your loom (most software requires drivers for the particular loom). You bring up your pattern file, and select the menu options to open communication with your loom and start working on that pattern. There are people in the chat group that I mentioned above that build and repair dobbies.