LulzBot… Soon!

LulzBot

LulzBot is know for producing and selling open source 3D printers, and in the spirit of open source, they do their best to give back to the community. In the past they’ve helped make Slic3r better, and more recently they’ve done a printer giveaway to hackerspaces… and yes, we’ve been chosen!

We are one of the LulzBot Hackerspace Giveaway 2014 Winners, and we’re pretty excited about it!

We (as a space) acquired a 1st gen MakerBot Replicator (the one with the wooden frame) and it’s served us well (ok, we never quite got the second extruder working, and it was down for repairs more than a few months last year.) Anyway, the MakerBot has been our best 3D printer to date, but with a LulzBot TAZ on the way, we’re really hoping to up our 3D game to include bigger and better prints, and hopefully explore new materials like Nylon, wood, and NinjaFlex. Being fans of open source ourselves (a makerspace is all about sharing!) it’ll be great to have a high-quality printer for our members as well as events like the Milwaukee 3D Printing Meetup.

Once we get the TAZ in and up and running, we’ll share the results. Thanks again, LulzBot!

Table Saw Guard

guard04

 

This started out as an experiment, but it’s working well enough that I might as well call it permanent.

Our table saw came with a blade guard that was attached to a splitter, and every time someone moved the guard, they’d bend the splitter out of position, so it didn’t line up with the blade. Instead of bending it back, people would just remove the guard and put it in some random place where we couldn’t find it, so a lot of the time we were using the saw without a guard.

Over-arm type guards are available, but some people have built their own, so I decided to give it a try. The Lexan sides and the spacers between them were cut out on the CNC router. Everything else was sized to fit the saw. (It’s made for a 10″ blade, but for some reason we have an 8″ blade on the saw right now.) A giant washer acts as a counterweight (it weighs about a pound).

I thought we’d have to fabricate a cantilevered arm from welded steel, or maybe some of the carbon fiber tubing that’s laying around. But first I built a prototype out of 2x4s, and it worked well enough that I decided to leave it that way (I replaced the two clamps with nuts and bolts after the picture was taken.)

splitter02

 

The new splitter was cut from 16 gauge sheet steel on the vertical bandsaw in the metal shop, then filed to fit, and bent with a pair of pliers to line up with the blade. It has slots in the bottom, so it can be removed by loosening the bolts with a 10mm wrench (for certain kinds of cuts that it would interfere with, such as dados). Since it’s not attached to the guard, it doesn’t get bent as easily as the original one.

For more info (including DXF files), see the wiki page:

http://wiki.milwaukeemakerspace.org/projects/guard

Camera Accessory Mounting System

CAMS pieces

Those who know me know that besides being cheap (hey, it’s part of being a maker and being DIY) I tend to use cameras a lot. Well, on occasion camera related things break, or I’ll need a part that doesn’t exist yet, or exists, but it too expensive, or isn’t designed right, or whatever.

All of the issues mentioned above lead me to create “CAMS” the “Camera Accessory Mounting System”, which will be a modular system that allows me to mount things to cameras, and mount cameras to things.

The connecting pieces of CAMS are 3D printed, and design is happening in OpenSCAD. The other parts of CAMS consists of standard 1/4″ hardware, nuts, bolts, screws, etc. There are also knobs that fit onto the nuts to allow for easy finger tightening.

CAMS Arm

There’s a wiki page for CAMS, which doesn’t have a ton of info yet, but you can also check out blog post #1 and blog post #2 about the arm.

Electric Ice Scooter

DSC_0424

When I recently was at the thrift store and saw a pair of ice skates next to a kick-scooter, it got my mind going. “What would a scooter look like with skates in place of wheels!?”

The next time I was at the Makerspace, I saw my old electric scooter over on the Hack Rack. This was a scooter I originally rescued from a dumpster. Although it didn’t have batteries, just adding power and a little tinkering got it up and running again. A few of the EV Club and PowerWheels Racing guys played around with the scooter a bit, but eventually the controller got toasted, and who knows what happened to the front wheel.

Oh well, I’d be replacing that front wheel with an ice skate anyways.

Turns out that the heel of an ice skate is actually sturdy enough to drill right through and use as a mounting point. I simply  drilled through the skate, inserted a spacer, and then ran a 3/8″ bolt through the skate and the front fork of the scooter. I finished it off with a couple of washers and a nut.

Then next thing to fix was to get the  motor going again. Turns out that it’s a brushless motor. While I have a fair amount of experience now with BRUSHED motors, this was my first experience with brushless. I did a little research, and then ordered a 24V, 250 watt generic brushless controller from a mail-order scooter parts company. Unfortunately, it used a different style of throttle than what was already on the scooter, so I had to order a throttle to match.

Connecting the controller was pretty easy, three wires to the motor and the black and red one to power. I first bench-tested it with an old printer power supply, and once everything was working right, bit the bullet and bought a brand new pair of 12ah SLA batteries. The two batteries are wired in series, along with a 20 amp fuse, and then go to the controller.

I still needed a deck for the scooter. I dug through some scrap materials and found a pair of cabinet doors that were about the right size. I cut them down just a bit and bolted them to the scooter. I even re-mounted a cabinet door handle to have as an attachment point for towing a sled.

With that, I was ready to go for a test ride, so it was off to the lake. Once I was on the ice, I turned on the scooter and gave it a go! What fun! It really zipped along, but it was almost impossible to steer, as the back tire would slip right out from under me! Time for more traction!

I decided to make a spiked tire. I removed the rear wheel, then disassembled the two-part rim and removed the tire and inner tube. I stuck 1/2″ self-tapping, pan-head, sheet-metal screws through the tire from the inside, so that their points stuck out.DSC_0394 I evenly spaced out 24 screws and alternated them to be slightly off-center side to side. Next, I put some old scrap bicycle inner tube over them as a liner to protect the scooter tire inner-tube. After that, it was just a matter of reassembling everything.

Now for test #2 out  on the ice. Remembering how much it hurt to fall on the ice, I was prepared this time by wearing my motorcycle jacket (which has padding built-in) and my helmet. Good thing too, as I would learn while steering with one hand and holding a GoPro camera in the other…. (Note to self, keep both hands on handlebars at all times.)

Overall, the Ice Scooter works great! I still have a few little things to do on it. For example, the motor is running “sensor less”, and I’d like to learn about how brushless motors use the sensor system. I’d also like to get a small 24V dedicated charger. As it is right now, I have to remove the deck and manually charge with a little 12V charger.

From thrift store idea, to hack rack, to life on the ice, it’s always fun to see what you can do with just a little ingenuity. I hope you like this project. If you want to see more on it, please check out the write-up I did on Instructables. It’s even in a few contests there, and I’d love your vote!

Keep on Making,

-Ben

Open Source Ecology in Milwaukee

Open Source Ecology

Marcin Jakubowski, TED fellow & founder of Open Source Ecology, will be visiting Milwaukee and speaking at three public lectures on the topic of Social Entrepreneurship.

Open Source Ecology is a non-profit organization with the goal of designing 50 industrial machines that it takes to build a small, sustainable civilization with modern comforts. The idea is that true economic power can be unleashed in developing countries when they gain access to the CAD files, how-to videos and other engineering specs required to make tools to build houses, agricultural equipment, etc.

(We’ve got a few members who are huge fans of Open Source Ecology and the ideas behind it.)

Open Source Ecology

Here’s the details on the three lectures taking place:

MSOE Lecture
When: Tuesday, February 18th at 7pm
Where: 1025 N Broadway St. Milwaukee, WI 53202
Multi-Purpose Room, Campus Center Building, 3rd Floor
more info

UW-Milwaukee Lecture
When: Wednesday, February 19th at 12pm
Where: 2200 E. Kenwood Blvd. Milwaukee, WI 53201
ANSYS Institute for Industrial Innovation, EMS Building, 1st Floor
more info

Marquette University Lecture
When: Wednesday, February 19th at 8pm
Where: 1637 W Wisconsin Ave. Milwaukee, WI 53233
WI Energy Foundation Classroom, Engineering Hall, 2nd Floor
more info

And here’s a video of Marcin talking about Open Source Ecology:

Our 4′ X 8′ CNC Router takes a step forward!

With a lot of hard work from Ed H. and Steve P. our 4′ x 8′ CNC router has achieved a milestone, instead of the X axis sitting on the ground it has taken a leap up and is now mounted, ready for the Y and Z axis to be mounted to it along with the electronics and motion control.

beam mounted

The X-axis is ready to be milled here.

The X-axis is ready to be milled here.

How to Build a Kitchen Table in an Assortment of Easy Steps

The Finished Product (so you keep reading)

14 - Finished1

So I moved into a new place and need furniture (which you might tell from the background of some of these photos). But, I kept looking at big box store stuff and it was expensive and poorly made. So I figured I could build something myself for cheaper and it would last longer! Plus I get to build something, which is half the fun.

Step 1: Find Inspiration

Chadhaus Furniture ($6,400)

From Etsy

Step 2: Design Your Own

I drew out a bunch of hand sketches to figure out dimensions and proportions. I actually wandered through a couple furniture stores and checked their measurements for a 6 person table… I also measured the room its going in to make sure I had space to get around it.

Then I pulled out my middle school drafting skills and an engineer’s scale to see if everything would work and kind of went from there.

Step 3: Buy Material

01 - 200 bucks worth of Cherry

This was something like 45 board feet of 6/4 cherry that I had roughly planed. By this point in the project I didn’t really know if I wanted rough cut lumber or if I was going to plane/sand/joint the whole top together as one solid piece.

First part of the bill, $200 for all this wood.

Step 4: Rough Layout

02 - Rough cut to size

I bought most of this material before I actually had a scale drawing I liked and before I had final measurements that I was going to build to. So I rough cut these to 66/68 inches long as I knew I would end up losing a bit of length during glue up.

Step 5: Build the Legs

Substep 5.1: Miter the steel for the legs.

The legs were 1×3 inch steel tube. 24 inch for the width and 36 inch stock cut to 29 inches long. So that plus the ~1.5 inch table top would be right about 30 inches high. (which seems about standard)

03 - Miter table legs

You can also see one of the dimensional sketches I carried around for reference.

Something like $120 for all the steel.

Substep 5.2: Learn to Weld

(Something something, draw an owl.)

My uncle taught me how to weld a year or so ago to build a similar looking entry way table so I had some experience welding before this. Plus I can soldier, which is nearly the same thing.

04 - First pass at welding

This was my first attempt at welding the whole set of legs into a square structure.

05 - Second pass at welding

 

This was the second set of legs. This set went a lot smoother as I figured out the process a bit and got into a groove for welding.

I also welded on the little tabs which I drilled out for 1/4 inch lag bolts.

Substep 5.3: Grind.

06 - Lots of grinding and flap wheel

 

Lots of grinding. Also I ground my name into the underside of one leg to sign my piece. I also finished these with a clear matte finish so that they wouldn’t rust.

Step 6: Assemble the Table Top

At this point I decided that I wanted to edge joint everything together and I wanted the top smooth so I didn’t get little crap in the gaps. So I took it back to Kettle Moraine Hardwoods and had them plane the rough lumber down to 1 3/8 inch and straight edge both sides. Then I put everything together once more for a rough layout.

07 - Last rough layout before glue

Substep 6.1: Biscuits and Glue

A hearty breakfast?

Because the boards were still kind of rough as I didn’t plane them down enough to get all the warp out of them, I decided to use biscuits to help the glue up and keep the top aligned and flat so that once I had to finish it I didn’t loose any more thickness. Also I tried to match up colors a bit differently than when I had rough boards.

(Side note, remember to alternate grain on each board to help prevent cupping)

08 - Give em the CLAMPS

Substep 6.2 Sanding

09 - Blank after glue up

So here it is after glue up. To save myself a bunch of time I took it back to Kettle Moraine Hardwoods as they have a 42 inch drum sander you can use for a couple bucks in shop fees. Then I transported it to the Makerspace to use the panel saw to square up the ends and sand it again to finish. (40 grit drum sander, 80 grit -> 180 grit -> 320 grit on the palm sander)

10 - Rough sanding on belt sander then finished by hand

Step 7: Finish

I really like oil based finishes as they bring out lot of the natural color and figure of the wood. Plus I had some lying around from that entry way table I mentioned earlier so I knew how the finish would turn out. (Velvit Oil)

11 - Oil finish vs raw

You can see the difference in color (sorry for the poor color balance) but the cherry has a beautiful redness to it. I also applied Paste Wax to the top as extra insurance against stains and water, etc.

Step 8: Attach Legs

12 -  Attach the legs

I kind of eyeballed this. But I did use a square and my engineer’s scale to try to align everything as best as possible. I did pre-drill holes for the lag bolts as there would be no way the bolts go in without them.

Step 9: Celebrate!

13 - Celebrate with beer

With beer!

Also I stood on the table to make sure it was stable, and it was. So that worked out.

Alternate shots:

With perhaps more natural lighting.

14 - Finished1

And a close up of some of the figure in the cherry.

15 - Closeup of the figured cherry

Conclusion:

So for $350 in materials ($200 for wood with lots left over, $120 for metal, $30 for shop fees) I built a table I’m pretty satisfied with. Plus its way cooler than MDF crap with veneer or paint to cover up crappy wood. And should last quite a while… I hope.

Robo-Barista – elbow motion added using one of the linear screws a member donated

One of the members dropped off a box of rejected 5 start lead screws. I measured the splines and 3D printed a lead nut that works with them and used it to make the elbow work. The lead nut seems to slide very well. I haven’t measured the backlash but I suspect it could be a bit tighter, or I could make a two part version with some backlash take up if more precision were needed.

The motor already had a drive pinion pressed onto it which I used as a spline by designing a coupling with matching teeth on one end and the rod thread profile on the other. Both ends are notched so they can be clamped down with a hose clamp. It seems to work pretty well. Peviously I was using a 1/4-20 threaded rod, and the motion was a bit too slow. This lead screw has 1.25 inches of travel per rev, and seems to match the other axes far better. Plus I think it looks cooler.

 

As before, if you like the project, please vote for me here (Paul Sisneros – Auto Barista):

http://www.element14.com/community/polls/1692?ICID=PSoc4-topbanner_vote

A robot barista, a new open source robot arm design, and a call for votes

This is a 5 degree of freedom (DOF) robot arm, with wrist tilt optional as a 6th. It is mostly 3D print ready in the way that most rep rap 3D printers are, meaning you still need a few stock pieces of metal, a lot of fasteners and rods, and some motors. I started this design with an all-nighter over thanksgiving break, and it’s nearly done. To explain why it’s called the Auto Barista, this is an entry in a contest called the smarter life challenge (I’m currently in 2nd place by only 33 votes for a trip to Germany and $1500, scroll to the bottom for how to vote) my entry was originally to make a smart coffee maker. I eventually decided that accomplishing the goal simply by piping ingredients from one process to another would be boring, after all this isn’t my work where I have to design the most efficient system possible, this is a contest, I can have some fun with it! So I decided to make a robot arm and have it run a coffee grinder, load the machine, pour the coffee, add cream ect. This approach is also modular since I can add new movements. When I thought of doing it this way it just seemed so much more exciting than doing it by making a big box, they have those at convenience stores, and besides this gives the maker community a new 3D printable robot arm design, and the PSoC platform (which sponsored the contest) software to run CNC machines.

The Design

Besides aiming to be easy for anyone with a 3D printer to replicate once I finish the design, I wanted to use some unique methods that I can’t usually put in my industrial designs, and to make everything reference back to the base. For that reason parallel bar linkages keep the wrist tilt aligned, and a linear rod which is almost a parallel bar linkage moves the elbow. If another screw were added on the linkage you could also motorize wrist tilt. For counterweight the wrist roll and grip motors are behind the elbow. A long drive rod with a 3D printed universal joint I designed runs the roll, through a set of gears, the wrist is held on with a large bearing which is clamped on the outside on one end and on the inside on the other.

To move the first link of the arm I made a large sector of a herringbone gear and mounted a motor on the first link which climbs along it. Besides being cool looking in my opinion, this gives me a 26:1 reduction in relatively little space without using an expensive gearbox. Since it was printed I webbed it out to make it more efficient to produce. Really this doesn’t hurt the strength since there are more thick walls in the directions where force is applied, though I haven’t done FEA to confirm that or anything.

Presentation1.png

exploded hand.JPG

The Build

The 3D printed parts (with exception of two small ones that need changes) are all done. I’ve machine the tubes for the body and cut all the rods, and I’ve wired up and mounted all of the motors. Software is also coming along quickly, the coordinated move hardware settings are working and I’m working on adding a communication stack to stream moves.

robot minimized.jpg

The Robot Arm In Motion

This video shows the robot arm with 3 of the axes of movement running in coordination. The motors for the grip and the upper arm are working, but I need to modify the motor couplers. I like how the parallel bar linkage and bearing on the wrist are working. I took some close-up video of the lower arm tilt gear because it’s one of my favorite details. It’s a 28:1 Herringbone gear, only the sector the robot needs is there and I webbed it out to reduce print time while keeping walls where it needed strength.

Currently the software is pretty simple. It is built on the method Max (an engineer from Cypress Semiconductor) provided in this thread. I haven’t yet added a USB stack or intelligence which would generate the moves. There is just a function called “GetNextMove” which currently gives back two positions alternately for all the axes, to show off the coordinated moves, and will later give back the next move from the com port. It will soon be able to do as many programmed motions as I want, and Coffee making steps will come soon after.

How the Milwaukee Makerspace Was Utilized

Most of the parts seen here were printed on my own 3D printer. Those that aren’t black were done at MMS, but one of the great resources I used was all of the parts I could freely try out to get things to fit. I scavenged most of the motors from the hack rack, got the metal beams from the rack in the metal shop, and pulled nuts and bolts from our hardware store shelves as needed. It really makes it faster (and cheaper) to not need a trip to the store every time you need a different bolt or nut. Plus you come up with some cool tricks, for example, the 3D printed claw is lined with rubber case feet, which give it excellent grip. I also used the mill to precision drill the mounting holes in the square tube, but that isn’t really required, I’m trying to make this design so that I can open source it when it’s done and if someone has a 3D printer and a drill, they can make it. One big change it will need to really work in that regard is a 3D print and off the shelf hardware based turn table, not everyone will be able to salvage a nice (though very used and worn) little one like I’m using. But that could have side benefits as other makers could probably use a design for a 3D printable turn table as well.

Please Vote!

I’m currently about 30 votes from the top in second place of the Smarter Life Challenge. The prize is a trip to Germany and $1500 in parts. So if you can, please take the time to create a user name and vote. It’s such a small margin!

http://www.element14.com/community/polls/1692?ICID=PSoc4-topbanner_vote

Here’s the link to vote (you have to create an account on the forum), I’m 13th down “The Auto Barista – Paul Sisneros”

More on plans to open source it?

Does anyone have advice about how to go about doing this? It seems like something that other people might like to use. I’m happy to share it once it’s all done and make a few modifications to make it more generally usable.