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.

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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.

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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.

MMPIS is fully operational

MMPIS

The MMPIS (Milwaukee Makerspace Pi-powered Informational System) has been moved to its permanent home and is fully operational. Witness the power of the MMPIS!

The MMPIS will let you know about the upcoming events on our calendar, display photos of members, regale you with silly quotes, tell you where to park, and make suggestions on what you should build next.

I can already hear you saying “Well that’s all good, but I need more info!” fear not dear makers, there’s a wiki page for the MMPIS with the BOM, other details, and links a bunch of blog posts about the creation of it.

(Thanks to a donated Raspberry Pi and big TV, minimal parts were needed to complete the build. If you’d like to see more MMPIS installations at the space, donate your HDMI capable TV and we’ll see what we can do.)

The End is Nigh!

Crazy Calendars!

Just a reminder that we’ll be skipping our regular Tuesday Night Meeting / Open Night this week so you can celebrate New Year’s Eve and ring in 2014. We’ll be back with our regular weekly meeting at 7pm on Tuesday, January 7th, 2014. Join us then to find out what we plan to make in the new year, or to share what you plan to make. Meet some members, take a tour, share and learn!

If you can’t join us on the 7th, no worries… We have our weekly meeting every Tuesday night at 7pm, and it’s open to the public to come in and find out what we’re all about. We’ve also got “Builder’s Night Out” every Thursday at 7pm. There’s no meeting, so people generally just focus on their own projects, but you’ll still find plenty of makers to hang out with.

Happy New Year 2014

2014, we’re ready for ya!

Weekend Project — Timed Outlet

I have a cordless drill with rechargeable batteries.  The batteries charge completely in about 20 minutes.  They are not supposed to stay on the charger for longer than that.  However, unless I am standing right there after the charging time, I forget to take the batteries off of the charger.

To fix this problem, I made a timed duplex power outlet out of a countdown timer and a duplex outlet.  I plug the timed outlet into a 120v outlet.  Then, plug the battery charger into the duplex outlet attached to the timer.  Finally, I set the timer to 20 minutes and walk away.  (There are more details about the parts and assembly on the Instructable.)

One problem I had is that the faceplate that came with the timer was too wide.  It covered the timer and a bit of the duplex outlet.  I found a Thing on Thingiverse that uses the Customizer to custom build faceplates that cover from one to five outlets with any configuration.  I used it to make a custom faceplate for two outlets with a single hole for the timer on the left-hand side and holes for a duplex outlet on the right-hand side.  I printed it on the Makerbot 3D printer using black PLA filament.  I used 100% infill to make it solid and durable.

 One problem I had with the print was that the raft stuck to the surface in some spots and would not come off.  So, there are a few rough looking spots.  Another problem is that the hole for the timer knob was a bit too small.  I had to drill it out slightly bigger.

 After attaching the new faceplate, I used my label maker to print the numbers for the dial.

That’s it.  No more ruined batteries due to overcharging.  And, it’s portable!

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Home Environmental Sensor Array (Phase 1) Finished

After six months of working on this on-and-off, I installed my home environmental sensor array (HESA) in my basement. Basically, it looks for water in the basement. If it detects water, it shuts off power to my water softener (assuming that the softener is or will, dump more water into the basement), and sends me an email.  The HESA has a Raspberry Pi to detect water and control the PowerSwitch Tail relay.  It also connects to the internet via my home network.

HESA

This is phase one of my HESA project. The device I built in this phase will only detect water. Future phases will add the capability to detect more things and be more interactive.

This is basically, my first real Maker project.  I learned or practiced many Maker skills like soldering, basic electronics, and CNC routing. I made my own PCB (that I did not end up using). I did some basic metal work with a jig saw. I learned how to use several software tools for CAD and design. I learned to program in Python. And I had a lot of fun doing it.

Several Makers at the Milwaukee Makerspace helped me with this project. There is no way I could have built this without them. Thanks to anyone who took time to help me move this project forward.

Wiki project page

Blog

Argyle Pattern Cutting Board

My latest cutting board is a based on a design I saw online.  It’s built around an argyle pattern that is often found on sweaters.

The first step is to glue a 1.5″ x 1.5″ pieces of poplar and red oak together in a 2 x 2 grid pattern. Additionally, one(1) red oak and two(2) poplar pieces are glues in a “L” shape. Each assembly is about 10″ long. Then, each assembly is sliced into 3/4″ pieces on the table saw or the chop saw. We need eight(8) of the 2×2 pieces and ten “L” shaped ones. The picture below shows the final intended layout.

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In the next step, the hard maple borders are added. The following picture shows some of the earliest glue-ups.

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Then, the edges are trimmed and walnut is added to the outside. I chose to use a CNC router to flatten the cutting board surface.

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I soaked the  board in mineral oil for 24 hours and finished with some butcher block conditioner and voila!

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Aaaaaand… Cut!

Silhouette Cameo

Hey, we got something new! It’s a Silhouette Cameo, which I like to refer to as a “Desktop CNC Cutting Machine”, though you can call it a vinyl cutter if you like. (It can also cut paper and fabric.)

I personally own one of these, and get a lot of use out of it, and I got sick and tired of hauling it back and forth to the space, so after posting a message on our email list to see if anyone else wanted to chip in and get one, we got one. In fact, there was so much interest we also got a bunch of vinyl, and spare blades and cutting mats.

The Silhouette has a wiki page, and we’ve already used it in a class. Now you can make your own crazy signs and other vinyl-covered things.

Further Adventures in CT Scan 3D Ego Printing

 

 

After a long series of manipulations, the CT scan derived  face was successfully used to make a pencil holder (of all things!).  It is about 100mm high and took about 9 hours to print.  You can find files that you can use to make your own mash-ups of my face on thingiverse: http://www.thingiverse.com/thing:203856

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Easy RTC Time Set

RTC Time set

I made a few RTC / LCD clocks and disliked setting the time using an Epoch converter so I found a solution that uses 2 buttons to advance the Hours and Minutes.  I substituted toggle switches for the buttons because I didn’t want to have to hold down the button while the Minutes were advancing, thus enabling me to move on to determining how long it is until Spring!.

RTC Timer