Roomba-Bot!

Today, I stopped in at the Makerspace with the plan to work on a small project for a Halloween party this Saturday.

The plan was to take a “Roomba” robot vacuum cleaner that I got for $1.00 at a rummage sale, and covert it into the robot base for a giant spider or some other scary creature that could wander around at a Halloween party.

I started pulling screws out of the bottom to figure out how to remove the brushes and vacuum blower. It took some tinkering to figure out what I could and couldn’t remove and not cause a fault. In the end, it didn’t look like I could remove the blower motor and still have the thing run, so I simply removed the fan blades from the blower.

By that time, I was now thinking about video cameras and how easy it would be to run a 1/4-20 bolt right through the plastic. A bolt and two nuts quickly made a camera mount.

In the other room were some ping-pong balls, and I had a black sharpie. A little hot glue and Roomba-cam has some personality.

Look for Roomba-cam running around the Milwaukee Makerspace and please treat Roomba-cam nice – he is watching you and WILL upload to YouTube!

-Ben Nelson

MegaMax Lives!

The video shows the last few layers of the calibration cube “printing” at 414% speed (according to my LCD display).

The Bucketworks 3D printing meet-up on 8/12 paid off big-time!  Gary Kramlich helped me debug a problem that was preventing me from flashing the firmware on the controller board for the MegaMax 3D printer.  After a few tweaks I was able to get it moving.

Android Blue or iOS Purple? Update on the OOMA project

The Object Of My Affection Lamp   I thought I would jump in and blog on my current progress at the Makerspace with a lamp called OOMA, or The Object Of My Affection. It’s a lamp that is shaped like a GPS Navigation pin that rotates to always points toward the one you love… as long as they allow you access to their Google Latitude account :). I am finalizing hardware designs and now moving into writing the software and how it talks to the Internet.

Initially I would have waived it off as using WiFi, or Ethernet, but work on another project (Marco) has illuminated several obstacles over multiple use cases (configuring Wi-Fi, closed networks, IP addresses); instead I think the approach will be to opt over USB (via Arduino Leonardo). I figure, if people will load up a coffee cup heater or foam missile launcher to USB, than there is no issue with port scarcity.

It’s not a lamp without light, and at some point OOMA will light up in either Android Blue, or iPhone Purple. Lighting the lamp will, however, have to relegated to a v.2 build, due to some complexity in the diffusion of light in such a cramped space. Additionally, I’d like to investigate EL panels to light it up.

Finally, I am coming up on the decision to be a DIY offering, or to design it to be marketable - do I build as a one off and just offer the blueprints to others or build an end-to-end consumer solution complete with potentially an NFC tag to tap and pair a user and their lamp.

MegaMax 3D Printer

MegaMax 3D Printer

MegaMax 3D printer based on MendelMax but bigger and minus plastic parts.

This is my on-going project at the Milwaukee Makerspace.  It is a 3D extruded plastic printer with about 1 cuft build envelope.  I want to print life-size human skulls (among other things) from CT scan data.  The printer is made mostly from salvaged parts and materials so the cost has been very low.  When it’s finished it will have a heated 12″x12″ bed (13″x13″ if I can find an aluminum plate that big) and dual extruder so it can print in two colors.

I have learned a lot on this project- some things that work and others that don’t work so well, and how to use a milling machine to drill holes precisely and square the ends of the 8020 extrusion pieces used to build up the frame of the machine.

I could not have done any of this without access to the people, materials, and tools at Milwaukee Makerspace.  Every time I go there to do some work on this project someone says something that gives me new ideas for improvements to the design.   I frequently find materials and parts left for me on the machine’s cart by other members who know what I’m trying to do.  If you have a project idea find your local Makerspace and get busy- there is nothing that will get your creative juices flowing like being around a bunch of people with similar interests and different skills and experience!

My neverending quest for quick turnaround prototype PCBs

For years I have dreamed of a fast way to prototype PCB for projects I am designing.

20 years ago I was using rub on drafting tape and stencils – slow and spotty results.

I tried to modify a plotter to plot resist directly to a PCB – no luck.

Magic markers – I’m no artist.

5 years ago I hacked a laminate router by tapping into the stepper controllers and adding a better Z axis – It can rout boards ok, but takes some tweaking.  It only does fairly wide traces.  But its great at drilling holes!

2 years ago I tried the inkjet printing systems – lots of smeared wet ink and poor registration, not very effective.

I opened up a laser printer and tried to get a board to go through it – almost worked, but the fuser was to narrow to take the board.

Although I haven’t found a fast system yet, I get by with the PNP Blue material and a good laminator.  Although I am regularly disappointed when dust, not quite clean boards, minor wrinkles and other issues leave gaps in traces that need touching up.

Which brings us to the latest attempt:

Now that the maker space has a small laser cutter I am trying to find something I can coat a board with and either burn away or melt onto the board to act as an etch resist.

Early attempts with paint had moderate results – our laser cutters on only 25W so it didn’t burn it cleanly.  I have heard that using flat black paint and a more powerful laser works.

Paste wax and markup fluid weren’t dark enough for the laser to vaporize (thinking of trying black crayons)

The latest attempt uses laser printer toner (just like the PNP only skipping the printing and iron on steps.)

The problem is how to get an even coat on a board without it blowing around.  Static electricity has potential (just like what they do inside a laser printer) but I don’t like the idea of a 5KV power supply exposed and handling powered toner is an automatic mess.

So for the first attempt I mixed the toner with rubbing alcohol (30% water).

Messy stuff!

I painted it on with the tongue depressor but it seemed to coat evenly and took only a few minutes to dry:

It mixes well and paints on fairly easily, here are some sample prints I did at various power and speed settings.  I cleaned the board fairly aggressively with paper towel and rubbing alcohol.

None are quite clean enough to become PCBs but they are getting close.

Although the toner paint looked dry, it may still have had some water in it.  I plan on trying a batch with denatured alcohol (100% – no water) and see if it works better.

 

2/16/2012

Updated progress

I have been trying a number of materials and methods to make my fast turn circuit boards.

I’ve decided that last toner is too messy and there are too many variables to create a repeatable process.  So now I’m trying various other masking materials:

 

Black and white spray paint – it works ok, but the ash left behind by the laser resists the etchant and leaves you with a poor etch.

I also tried tape:  Painters tape, electrical tape, clear and brown box tape.  The masking tape worked ok until the etch was slow and the tape started to dissolve.

I held a few of the boards up to the light so you can see how it etched:

 

 

 

 

 

 

One of the other members of the space found someone who had made the black paint work.  The process is to do 2 passes with the laser – the first burns off the paint, the second burns off the ash!  Then you wipe the board down with rubbing alcohol to clean off any residue.   Here is a set of 3 projects I lasered and etched at once:

This board turned out rather well, I had some trouble with the etchant taking for ever so lost some of the detail on the lettering, but the boards came out nicely.  I should get even better results on the next project.

In an attempt to speed the entire process up I tried to drill holes with the laser cutter from the back of the board:

   Not very good results!  After about 6 passes it still didn’t cut through thin PCB material and stunk and smoked the whole time!

 

 

 

 

 

 

So instead, I used the laser to cut wholes in a small piece of acrylic to use as drill guide:

 

 

 

This gives you a pattern to follow using a Dremel and the holes wind up in the right places and nicely lined up.  I drilled 2 holes in opposite corners of the board and used the leads from resistor to line up the template and board and hold them together while drilling.

 

 

 

This image shows the template attached to the board and about half the holes drilled.  This worked very nicely!  The only problems was small disks of acrylic getting stuck to the drill bit (you can see little craters on the left side of the board where these came from)  I had to clean the drill bit twice to drill the whole thing.  Either bigger holes or a different plastic might fix this.

 

This is first of the 3 boards I put together and it works just fine.  It is a level translator for the encoder you see in the holder.  The encoder will be attached to the drive motor in my electric car and feed back motor position to the controller.  The encoder is 5V and the controller wants a 15V signal.  The test bed uses a 15V power supply and LEDs on the 4 quaderature outputs.

Encoder test video

Project Roundup 5/12

It’s been one month since our Grand Opening.  We’ve added a few new members and some new equipment!  Here’s a quick trip around the shop to see what’s going on:

Brent and Jackie are building a vacuum forming machine to mold plastic.
David has a quad copter kit he’s building that when done will be able to lift 1.1 kilograms! 


Richard used the jig saw to cut out wood blocks for a Daft Punk helmet prop he’s making.

Kevin and friends spent time welding metal to a bicycle wheel as part of an joke gift sculpture.