So lately in 2016 (and quite a bit today) i’ve taken a look at revisiting my original DIY Taffy Pulling Machine from 2012. There was a lot of interest in the 2012 version, and i did try to provide enough information and detail in open source fashion for others to build their own, but i guess things just didn’t work out the best for that to happen.
The biggest reason i revisited it is because it just didn’t quite feel finished, and quite frankly those big gears posed a pinching hazard. Plus many people didn’t know where to get their own. So in an effort to solve both problems in one i decided to make internal gears, but to do that successfully i had to shrink them down. In the process i decided it was time to make the gears 3D-printable thereby speeding up my own design process, but also opening up this design to a whole new set of people that otherwise would not be able to make one.
I hereby am pleased to announce the re-releasing of my Mini Taffy Machine as an Open Source Hardware project. I have improved the CAD files and PDF assembly drawings with good blueprint title blocks (a skill i obtained from my recent machining courses this semester). So i hope you all enjoy and i look forward to seeing more of these in the wild and new iterations and modifications that people come up with!! (http://www.thingiverse.com/thing:1659568)
So despite the blog and my internet presence being quite mute as of late i actually have been up to quite a lot. My homemade Lulzbot Mini 3d Printer this summer was a success, amd i have constantly been improving it. At some point i will take some photos of it’s final progress. A few of my pea breeding crosses from last year were successful, including one i’m excited to grow again which is a cross of the Purple Passion dark purple seeded pea (which is a small genetically weak pea variety) with another stronger pea variety. That should produce something really cool in the coming years. And this fall and next spring i’m experimenting with school by going through a Precision Machinist course and am learning how to use milling machines, lathes, and CNC equipment to produce Aerospace quality components. Not sure if that’s something i want to do long term, but they are skills i’m interested in and can use throughout my life. So that’s new.
Anyway though, as a throwback or a revisit to my post in 2010 titled “Do Plants Really Need Sunlight?“, which has actually been one of the most visited posts on my blog over the years, i finally got around to building a few of those coils that sounded so interesting.
So the basic premise or idea behind using a coil of wire with electricity is that it produces a small amount of electricity or a magnetic current through the air. This is the same idea Nicola Tesla was after all those years ago when his imagination was captured with the idea that everything could have wireless electricity. And in many cases his dream has come true with an ever increasing amount of technology these days using induction to wirelessly power or heat things. The basic premise of applying this technology to plants comes from an articlei read once that talked about how researchers were able to measure a small direct current from trees in a forest by placing nails in them. They then had ideas about placing nails in many trees and hooking them up together to power small electronics like a battery or cell phone charger, or a smoke alarm. Basically all plants (and maybe all living things) produce a bioelectric field of energy. If one can tap this field to harvest electricity, then why cant we tap into it and feed these plants with extra electricity to help them grow.
One question i asked in my old blog post was if plants even need sunlight at all as long as they are getting some form of energy to grow. I still haven’t done an experiment to test that idea, but it’s still an interesting question. Because it makes me wonder if there are ways plants could be grown in complete darkness.
Regardless, this summer i finally built a prototype plant coil. I built it rather late in the season, so i really wasn’t able to give it a good test. My original plan was to plant 3 or 4 genetically identical tomato plants near each other in the relatively same soil with at least one plant being the control. I was then going to observe over the course of the summer f the tomato plants within the coils had larger and better growth than the control. That was plan anyway, i just didn’t quite get to it.
You can see here we were trying to use a volt meter and another coil to see if we could detect that our coils were working. We weren’t having much success with the meter in the beginning and i don’t remember if we did later after increasing the power supply a bit. But in theory you should be able to measure with a second coil.
I placed it on three smallest tomato plant clusters in the very late planted tomato patch. Interestingly enough, the three plants it happens to be on might be the only three blue tomato genetic varieties that survived my haphazard tomato disasters this year. Since placing the coils on these plants i have noticed an improvement in them and they have since catched up to the growth of the other tomato plants in that spot. Although at the same time i did also make a furrow and started watering them more. But even so i’d be willing to go out on a limb and say that the coils did help them go from “runt” status to catching up to the others. I may yet get a few tomatoes from the larger two before winter hits. Thanks to Gilbert for providing the motivation to actually build this project. And a thanks to the Homegrown Goodness plant breeding forum where i get so many of my adventurous gardening and plant breeding ideas. You guy’s are the best and a continual inspiration to me. Read more: http://alanbishop.proboards.com/thread/8623/breeding-tower-potato-ideas-wanted?page=13#ixzz4LoiDtFZE
So, while my experimentation was a bit haphazard this year i think i still did ok. It was a fun project that went from an interesting patent to a cool project idea in my head and at the back of my mind, to a fully functional project / prototype. Plus i think these coils look cool. haha.
But it makes me wonder what other cool patents are out there that i can exploit, reverse engineer and build to experiment with. One of my next projects i think will go the opposite route and will be heavily steeped in Open Source as i think i will try and build a “Food Computer“. Basically it’s a small climate controlled aeroponic grow box. It should allow me to continue my plant breeding efforts even in the winter which is really what i want. Plus it will allow me to learn more about this “urban gardeng”, “vertical gardening”, and “aeroponic” stuff. I can’t wait to get back to pea, bean, and tomato breeding even though the summer and fall are waning fast. I think i’m going to repurpose my 2ft x 2ft t-slot frame that i was intending to turn into a large 3D printer and/or CNC mill. But it’s still going to be a long time before i finish that project, so i figured hey why not actually use it for something useful in the meantime! So.. that’t the plan.. 😀
So recently i’ve finally gotten my homemade / homebuilt Lulzbot mini working. And it’s working pretty good. The most critical problem i was facing was that my 3d printer would start printing either too close to the heat bed (or if i added extra bed leveling washers) it would print too far away. This was a critical problem as the first few layers are the most important and if you can’t get you prints to stick to your print bed then the rest of the print will usually unstick and fail. Thanks to some helpful people on the Lulzbot forum i was able to adjust my z-offset to the correct height that worked for me.
The second issue is that recently i’ve noticed my large and tall prints failing miserably at a certain height and the filament not coming out thick enough and the top gets all cob-weby like a spider web, but worse. Apparently this is called “Heat Creep”. The problem in part may be caused by the tiny blower fan on the Lulzbot mini not providing enough cooling and heat slowly rising in the hot end until the filament actually melts too soon and cannot be extruded properly. This makes sense as the problem only occurs after a long time printing. So the logical step was to replace the tiny blower fan (or squirrel fan) with a larger fan that will do the job. The new Taz 6 has obviously taken that tiny fan into consideration and has changed it to a large 40mm fan.
EDIT: The failing on large prints may be due to me using a half-size stepper instead of a full size stepper motor for the extruder. This means too much voltage is being applied to the motor and it is getting super hot. Over time this means the motor looses steps and probably causes my printing problems.
Unfortunately the Taz 6 x-carriage and modifications are not a drop in replacement for the Lulzbot Mini i decided to make my own. This is what i came up with and it seems to work beautifully. http://www.thingiverse.com/thing:1587110
I have only tested this on HIPS so far, but it has eliminated the heat creep i was getting with HIPS. PLA apparently suffers more from heat creep problems than other filaments, but this mod will likely help with PLA heat creep issues as well.
Today i made significant progress on building my own Lulzbot Mini 3D printer from scratch. Technically i now have two 3d printers i’m building from scratch, but the other one is bigger and one i’m designing myself. Just like me to not finish one project before starting another. At least i’m going to work on this one and finish it before continuing on my other one (which might be converted into a homemade CNC mill).
Today was a major milestone because most of the components are put together and i finally was able to test part of the electronics i wired up myself. I was able to test the Y-axis motor and limit switches as well as the X-axis stepper motor. All seemed to function correctly using Lulzbot’s Cura software. The software did have an unexpected safety feature however, it wouldn’t let me turn any of the motors on without the bed thermistor wired up. So i had to wire up a temporary 10k thermistor for testing purposes. It worked great. I was running the Cura software under Ubuntu Linux. The Cura software gave me an error that it could not autodetect the serial port or something like that, so i ran it as the root super user and that fixed the problems.
Since i’m building this thing from scratch instead of buying one premade i’m trying to find ways of cutting costs. Although i think i will end up spending more than i hoped. But anyway, part of that is looking into ways that i might be able to replace expensive commercial products like the IGUS bearings and the Leadscrew nut. I’ve already drafted up a 3d printable version of the leadscrew nut and posted it here on Thingiverse. The nut has yet to be tested, but i’ve also had some RJM-01-08 IGUS bearing replica prototypes made in Nylon. The RJM-01-08 IGUS replica bearings turned out to be too tight, but with a drill i was able to make them usable. They are currently being used to remove the wiggle and slop i was experiencing from using the 1mm too small LM8UU ball bearings.
I originally got the LM8UU bearings as a cheaper alternative to the commercial RJM-01-08 IGUS stock bearings the Lulzbot mini uses thinking they would work. They work, and i am currently using some, but the stock STL files from Lulzbot have holes that are 1mm too big because of the slight size difference between them and the LM8UU. I might try to modify the STL files [i have modified the lulzbot solidworks files] to make LM8UU compatible parts in the near future, but for now i’m happy with my 3d printed nylon ones. I’ve heard PLA might work too, so i will experiment with that in the future as well.
So today i had an interesting experience. As i have been lately, i sometimes go to the library to print out parts I’ve designed for my custom 3D printer project. While they print i use the time to crunch out upcoming essays for for school.
But this time instead of the printer happily moving along and producing perfect parts i got a rude awakening. The parts that came out looked like picture #3. Instead of my corner pieces being printed with two triangular pyramids and four “arms” they printed with one triangle, a “tail” and two “spaghetti blobs” on the side in a mess. It looked more like a deformed geometric fish instead.
Looking for info online i found helpful information on the Ultimaker Forum. It seems if i go into Layer view beforehand i can see what it will print out like and see any obvious gaps before hand. X-ray mode is even more helpful in a situation like this because if there are any faces or walls that have problems they get highlighted in bright red.
As you can see on mine, the bad models have several red triangular “internal” walls. The models have internal walls because they were created in Solidworks as assemblies from smaller parts and “digitally glued together”. Normally that shouldn’t cause a problem, but for some reason it did.
Currently i’m using Solidworks 2007 to create my 3D models. I wish i could use a good Open Source CAD program that works in Ubuntu Linux, but sadly none really exist. Not to my liking anyway. FreeCad has potential, but has a long way to go. OpenSCAD looks decent, but is for people who have mathematical minds. Sadly i don’t. And Blender has amazing graphics, but is not a CAD program. If someone could combine the beautiful elegance of Blender while stripping out it’s over-complexity and merging it with FreeCAD, and taking the user friendliness of Solidworks it would be perfect. Oh, and it has to be cross-platform (meaning runs on Ubuntu Linux). So until that day i’m forced to use a proprietary CAD program on a otherwise useless proprietary operating system, either on it’s own machine (or run in a virtual machine like Virtualbox). Far from an elegant solution. -End Of Rant. lol.
For me my problem was some sort of issue with the internal walls. Normally this should not be a problem. Since my version of Solidworks does not export whole assemblies as STL files (instead each separate part is exported into STL), I’ve been using 3dContentCentral to convert my CAD files into single STL files. Apparently the issue i ran into arises when i export my assemblies into single part files before converting them to STL. If i instead upload the entire assembly (and dependencies) and convert those to STL files it seems to work fine. Somehow that makes a difference when fixing whatever was wrong with those internal walls/faces. Whatever. At least i’m happy to find a solution.
I wanted to fix my bad CAD models from the beginning, but for example if i had a bad STL file that was not created by me and i still needed to print it, i could turn to Cura’s expert settings. In Cura’s expert settings there are some tools that attempt to “fix horrible” models that would otherwise fail to print correctly. I could have gone that route to print them anyway, but for me the better solution was to fix the source of the problem which was a bad CAD model.
So, all in all, check your parts before you print them. Cura’s x-ray mode and layer mode are invaluable tools that can help you avoid problems with your 3D printing endeavors.
This site also gives some good tips on bad edge geometry and bad STL meshes.
One of my newly resurrected projects is my ambition to deign and build my own functional 3d printer. Eventually i’d love to just purchase a nice one, but i’d also like to build my own (besides i already have most of the parts and mine would be bigger too). The pre-made model i would buy is the Lulzbot mini. Mainly because they are fantastically built machines, but also because they are produced by a company here in my own town! Plus they have a philosophical commitment to open source which i love.
Anyway, building off of my original post in 2011, I’m designing from scratch a 2ft x 2ft 3d printer. I’ve been steadily making good progress piece by piece, step by step. My main design criteria are: as close to a 2ft x 2ft build area as possible (maximizing build area vs machine footprint), using 1″ 10 series 80/20 t-slot extruded aluminum, minimizing unneeded parts by using t-slot linear bearings (real aluminum ones and 3d printed working replicas), and trying to just have a simple design by default. I’ve had fun these last few weeks by printing out working 80/20 linear bearing CAD models into working plastic prototypes. My next step is to print out some motor mounts. I’ve designed two motor mounts so far. The first one is a snug mount that shapely fits around a motor and has built in t-slot mounts intended for the z axis lead screws. The second is a simple right angle slotted mount for y-axis that has a belt drive. I have them modeled in Solidworks 2007. I just need to print them out to see if they will work.
I think i’ve finished the design for the XYZZY Motor Controller, which for me is a big statement. I embarrassingly probably even said it before too. But anyway both the top board and the bottom board are done in Eagle Cad and i think i’m satisfied. The top board relatively stayed the same since it’s design was fairly sound. All that was needed was a few safety diodes for the mosfets, some led’s, and some minor resistors which were not critical. The bottom board was another story however.
It required a complete redesign except for the basic underlying parts. Many of the items i had on the board were just potential “goodies” that were extraneous and non-critical, so i removed them. Not only did it help remove extra unrouted wires, it helped clear up some much needed room. In the end i ended up with some extra room that i turned into a tiny proto board area that i’m quite pleased with. Along the way i fixed a few errors on the schematic and routed things nicer than they were before. I think all that it needs now is to order up some PCB’s and do some more testing and programming.
The only things i would like to change are the screw terminals. The ones that are on the schematic now are much too small for a large amp motor. The problem is i can’t seem to find an Eagle Cad footprint for one. I may have to end up creating my own part in eagle cad eventually. If you know of one please let me know in the comments below! I’m looking for something like these: photo1, photo2, photo3.
The XYZZY Motor Controller is a modular open source hardware mosfet speed controller h-bridge. It has been designed to be able to handle high current motors with the parallel mosfet design. It has been designed to be hackable and DIY accessible (hence the all through hole design). It has been designed for flexibility. Since it has been created with the hope in mind of a built-in arduino brain it can be easily programmed for many things. I’ve routed one PWM capable I/O port to function as a PWM directional input (modeled after the IFI Victor 884 servo input design). But one feature i’m happy to include is an easily accessible I2C port. This port gives the motor controller many potential abilities. One idea is to use the I2C port to expand it’s capabilities (such as a current sensor), or i think it would be cool to use I2C to daisy-chain several motor controllers together to help save wiring and to provide real-time feedback to a master microprocessor or computer. Another cool “feature” is that possible boards could be fixed with half the parts. If for example the mosfets died for some reason, but the bottom components were fine (or vice versa) you could use the good parts with other good parts. Since my old top board is basically the same i plan to test it with a new bottom board sometime in the near future. I expect it to work fine.
The schematics are somewhat rough. I’ve tried to clean them up as best i can. But don’t expect them to be pretty. The reason one schematic has floating wires going nowhere on one side is that at one point these were part of one schematic. To create the two board system with the pluggable pin headers i had to split them into “two projects” at one point in time.
If you would like a copy of the current Eagle Cad files please let me know. This is an Open Source Hardware Design. I would love to see these in the wild or even improved versions of it. Perhaps someone with surface mount experience can create one with smaller parts. More prototype testing to come soon, i hope! 🙂
Update (9-15-15): I’ve updated it again only slightly. I’ve changed the resistors to have bigger pads using the adafruit eagle cad library parts, and instead of screw terminals i’ve decided to use spade connectors or quick disconnects. These make it less cumbersome to disconnect motors and power and no loosing of screws, but also saves space (which was more critical). I couldn’t find a library that had a spade connector already, i had to make it myself. It actually wasn’t too hard.