Synthetos

PCB Cyborg Art

So I had some free time while waiting for Alden to proof my xproto breakout board I designed for the tinyG system that we are working on.  So I took some time to try to mimic the results that Joe Grand of Grand Idea Studios did on his professional PCB mill.  I think the results were pretty good.  In fact they were even better than you see on the final version.  I say this because currently I have a very coarse wire brush on my grinder and did not take the time to switch it to a much finer wire gauge.  I was lazy.  As you can see some of the building is coming off.

Also in the middle there was some “over burn” where I left it in contact too long.

This has kind of inspired me to do some neat graphic / electronics.  Not sure what I am going to do but this would have been much cooler if the cyborg’s eye lit up and would blink faster / slower based off of the temp in the room etc…

Tags: art, defcon, etching, laser, pcb

First steps to a complete robot arm

The oomlaut open source robot arm base assembled easily and looks slick and professional.

Thanks to Riley, I am the proud owner of a pile of lasercut parts for the uber-cool oomlaut open source robot arm. The details can be had from both the original blog post and a thingiverse.com post that has the necessary design files (nicely laid out for the lasercutter, although Riley was able to get the layout down to a single 12×24in sheet, which was great. He said he will upload it as a derivative on thingiverse ASAP, so others can benefit, too.) My daughter and I both thought watching it cut was the coolest thing ever. She has taken all the scrap and has it proudly displayed in her room, too. It helps that the color we chose was bright red- gives it a gem-like (and somewhat sinister!) appearance. Can’t beat that!

I have most of the electronics already- I will be using a barebones Arduino as the controller, and a Pololu servo interface board to maximize the precision. I did have to order some good metal-gear servos, which I got for a steal at dealextreme.com The total cost of the project will be about 70$US, and if I had to buy everything fresh, closer to 100$US. Pretty good for a flexible robot arm and experimental hacking platform. My intent is to incorporate it into some work that colleagues and I have been doing around automated lab testing. I intend to borrow an existing reverse kinetics framework and use that for path planning. I am also going to rework the gripper, as I think it is the weakest part of the design.

Next up will be an illustrated build diary, here on the Synthetos blog, and a compete set of instructions, ordering guide, etc., over at Instructables. The goal is to get the arm built and tested, and to validate the design, as well as get others interested in building their own. Who knows- if it works out well, I may even take a crack at a derivative design that can be built using only RepRap-ed parts!

Tags: robotics arduino lasercut

MUSAMP

I was browsing G Randy Slone’s High-Power Audio Amplifier Construction Manual (great resource!) when I noticed he had some sample PCB layouts in the back of the book. Although he mentions that the layouts are dual sided, they’re really single sided, with components on the other side. The PCB layout sheets are a bit confusing because of this. He has a negative of the ‘top’, ‘bottom’ and combined top and bottom which is really the see through of the two layers.

I picked the ~250w amplifier for musical instruments (short circuit protection, etc) which is not the best performing of the bunch but is a good compromise between complexity and performance.

This is probably copyrighted, but it just to get the idea (fair use)

Armed with some copper clad and spray paint, I went over to the Synthetos Laboratory for some rapid prototyping of this 0.05% THD amplifier. Step one is to paint the copper clad with spray paint primer. Step two is to import the layout (scanned at 1200 dpi-native res for the lazor etcher), cleaned it up a bit in Photoshop then presented it as a print out to the Laser Etcher.

Laser Etcher about 50% through the Copper Clad

As you can see, the laser etcher prints on the copper clad by removing the spray paint primer, which exposes the copper. Next up, is the traditional Ferric Chloride solution which removes the copper from the clad material.

Removed Copper

After etching, the exposed copper dissolves in to the Ferric Chloride solution (oxidation/reduction?) and what is left is the covered copper (with spray paint primer) and the see through clad material. At this step, I tried to use Paint thinner to remove the spray paint.

Notice the Sponge Brush

The sponge brush that I got from the paint section at Home Depot is a great tool. Along with a plastic/rubber paint tray, I was able to use only a small amount of Ferric Chloride to remove the copper. Basically I poured a small amount in to the plastic tray, and brushed the copper clad continuously until the copper came off in about 15 mins. No heating was required, and compared to the amount of Ferric Chloride saved (vs using complete submersion), this was well the effort.

Unfortunately, the paint thinner didn’t quite work, or maybe I didn’t rub it hard enough. I then used some nail polish remover (Fisher Scientific acetone passed away) and some #0000 steel wool to remove the paint. Below is whats left.

Close Up of the Finished Board

A nice feature of the laser etcher is that it works on so many different materials for just as many uses. Below is the ‘top’ side print of the components.

Components Side Print on the Single Sided Copper Clad Board

The beauty of this is that all of this was done, in one evening!

And now, I’m off for some classical music!! Ciao.

Magnetic Linear Encoder – and it works :)

For awhile now I have been meaning to try to find a way to close the stepper motor “loop” on CNC devices.  What started as an need / idea turned into reality last night.  A few weeks back cruising thingiverse.com I found a post where Zach had created a magnetic linear encoder.  However his design was off and needed fixing.   Instead of re-inventing the wheel with a different linear magnetic chip I decided to use the same setup as Zach.  I contacted him about fixing the problem with the board (the footprint was off) and in about 3 hours after emailing him he had it fixed.

I have blogged about laser etching PCB’s in the past (you can read about it here).  The inherit problem with laser etching PCB’s is that is it very hard to get aligned if its a double sided board.  So I modified Zach’s design to be a single sided board.  Its tight in some spots but if you use the solder mask I created and have a somewhat steady hand its doable.  Here are some pictures of the process and a video of it working!

The AS5306 can be found here:
http://www.austriamicrosystems.com/eng/Products/Magnetic-Encoders/Linear-Encoders/AS5306

Thingiverse entry and files here:
http://www.thingiverse.com/thing:1409

Tags: arduino, AS5306, austria micro systems, linear encoder, linear motion, makerbot, pcb

Laser Cut End Mill Holder

As you know I recently purchased a milling machined to be able to do some custom PCB stuff along with some intro level metal working.  Well today I thought that I would try to create a collet holder that would have its sizes clearly visible.  However being short on time and on a break from some “real” work I made an end mill holder for my 10 piece set from grizzly instead.

I am using a method that I invented I termed:  Self threading square tube insert method. Whats so cool about this is it combines fairly easy cuts of aluminum that pretty much anyone can do with a band saw, hand saw or rusty pocket knife… Well not the last one and I don’t suggest you try it.  But is very cool.  Basically its all in the spacing of the 4 holes that were laser cut that the aluminum sits below.  Its a very tight squeeze which allows the screws to “self thread” inside the square tube’s inside.  Hence the name.  Not super witty but it describes it nicely.   Comments, questions or concerns always welcome.  Next thing to make is the collet holder.

Here is the final results:
http://www.thingiverse.com/thing:1393

Thingiverse Links as always here:
http://www.thingiverse.com/thing:1393

Tags: DIY, end mill, laser, Laser Cutter, Metal Working, mill, useful

Laser Cut Cleaning Tool

So my workshop was begining to become littered with metal bits from my new Grizzly G0463 Metalworking Mill.  So I got a good deal on a iROBOT dirt dawg.  This little guy has been great.  I have been a long time consumer of the iRobots but have found that having 3 100lbs+ dogs tend to “tire” the robots out faster than normal.  That being said this shop cleaning robot seems to preform as expected cleaning the workshop.  In all honesty I am very impressed with it.

However, My metal cutting table has clamping T’s that little bits of metal would fall down into and become very much of a pain to clean.  So I decided to fab a part in google sketchup for the T slots to help extract the junk.  So a few quick measurements with my digital caliper and I was good to go.

Thingiverse Part Here: http://www.thingiverse.com/thing:1372

Here is the final product:

Tags: G0463, Grizzly, laser cut, Laser Cutter, laser cutting, metal mill, mill, News, workshop

Bus Pirate V3 Enclosure – Alpha

This is my first attempt at creating a custom enclosure for the Buss Pirate V3. I think these plexi-glass cases are pretty awesome. They take very little resources to make and can be pumped out pretty quickly. On the opposite side (see below) I etched a “cheat sheet” on the bottom for quick commands.

I could not find my spray paint last night (due to re-organizing my workshop.. I guess a little too well ) so I used a magic marker. This provided ok results for the prototype but if you zoom in perhaps you can see that the letters “bled” a bit. I will fix this on the next version. I like the size of this enclosure but I am thinking that the top might benefit from 1 more 1/8 layer or possibly a 1/16 layer to cover the USB connector. I will post this on Thingiverse in the next few days.

–Ril3y

Tags: buss pirate, laser cut, plexi-glass

Laser Etched PCB’s Take 2

UPDATE:  I forgot to attach the image file I created to allow for the laser to cut the holes in the PCB.  I will attach it later today (5 – 6PM EST).

As promised I was going to continue to research ways of using the laser cutter to make custom PCB’s quickly.  The results from the last trial were very good.  However, I thought that I could do better by having the laser cut the holes for the components also.  The problem with this is epilog c02 lasers (the one at least I have) do not produce high enough energy to “react” with copper.  So over every trace I have embeded a small circle that allows during the time of ferric chloride etching will remove some of the copper as well.  You can see this here.  What this does is make a very small circle that does not have any copper on the top.  This will allow the laser to cut the 1/32 silicon PCB board.

CONSTRAINTS:

Alignment, alignment and  alignment – I have not come up with a good “template” or “jig” yet to allow for hole cutting once the PCB copper has been removed.  Also this precludes me from using double sided designs as well.  After talking to Dr. Mark Adams he has proposed an interesting solution to this problem.  His idea was to, through eagle regenerate the bottom side of the PCB by changing the rules so that the traces are larger and would allow for higher offset tolerances.

Rack and Pinion Attempts…

My first attempt at a rack for a rack and pinion setup on the laser cutter.. All by hand in sketchup.. not super great so far but getting close… Once more unto the breach..

Tags: laser, laser cut, Laser Cutter, laser cutting, lasercutter, pinion, plexi, plexiglass, rack, rack and pinion

608 Bearing Wrapper and Gear

I got this idea from the makerbot guys.  They used 1/8 plywood to create theirs however I went ahead and tested with superglue and 1/8 plexi glass.   This method seems to work very well.  Here is the link the thing on thingiverse: http://www.thingiverse.com/thing:1203
Here is the link for my flickr page on it:  http://www.flickr.com/photos/31697990@N00/sets/72157622572234151/

Tags: 608, 608 bearing, bearing, rotation, rotational