Tuesday, May 24, 2011

3D Printing

I've been working on a project involving numerous small PCBs being deployed in high-traffic industrial areas. I really need enclosures for these devices that can be robust enough to handle some bumps and bruises. Unfortunately, custom enclosures are very Expensive, so I talked my Boss into buying a Thing-O-Matic from Makerbot.com !! YAY!This is a 3D printer. Basically that means it has a CNC platform that moves around while molten plastic is extruded in a pre-defined path. Kind of like at the beach when you dripping wet sand from your fist to make a tower. This technique allows you to make a drawing in some free modeling software like Google's Sketchup and then print the actual object out in real life. In the image above, the printer appears to have just finished printing out a baby rabbit. How cute.

I received the printer a few weeks ago and have been working furiously at assembling the thing, learning how it works, and making some test objects. Here's a video of the Printer cranking out some custom enclosures.

When I say "Cranking out", I really mean "piddling along at a snail's pace," because that's what these 3D printers do. Fortunately, however, there's a conveyor belt on the printer, so you can just set it to print 50 units and then walk away for a couple of hours. When you come back, you'll have a neat little pile of them sitting in front of the printer.

The tech is similar to stereolithography, which is an incredibly expensive process involving a vat of photoactive chemicals and lasers and stuff. The Thing-O-Matic is only about $1300, though, plus there's this really cool community called Thingiverse where you can download designs for all kinds of stuff you might want to make, like the Gothic Cathedral Playset.

Unfortunately, after a couple of weeks of printing, one of the stepper drivers blew out. This appears to be a very un-common problem, but Makerbot was kind enough to replace the device for me, and I should be back up and running any time now.

Here's my Thingiverse page:
You can see the auger I designed and printed for pushing cat food through a pipe.


So we're calling it the BrickShield now. Don't want to get an angry phone call from the lawyers at Lego, or even worse, some kind of cease and desist.

But it's done! I actually got the PCB back from batchPCB a while back, but have been a little too busy to post about it. Here it is, Start slobbering.

Power select jumpers on the right

You can see it has the Mindsensors NXT port I posted about earlier. This is connected to the TWI pins for "easy" communication with standard NXT devices.

Yellow wire coming from the V+ line

One of the big things I wanted was MORE OUTPUTS, so now we've got simultaneously:
-4 Amplified Digital outs (total of 4 pins on left)
-4 Amplified Motor Outs (total of 8 amplified pins on right)
-4 Servo Ports (below the NXT port)
-Digital lines 0 and 1 available for communication with PC or Radio
-Header for BlueSmirf at top
-Passthrough headers for mounting another shield on top
-Integrated V+ port for higher voltage in drivers
-5V/V+ selection for each via jumper (Servos, Digitals, Motors)
-Optional ICSP pass through for powering additional boards with the 5V line
-Offset header slot on the digital side to allow use with standard perf-board
-Extra 5V an 0V lines by the analog inputs for easy sensor powering

Anybody recognize the LED board on the right?

Below you can see what it looks like with the Libelium Xbee Shield (which I use frequently for RC Projects). If you so choose, you can forget the communication shield on top and just control the Arduino and Brickshield straight from your PC using Arduino Animator.

So I'll be sending these off to a couple of distributors to see if they're interested in selling them. Probably will start with Sparkfun, Makershed or Mindsensors and see if they are interested.
If you'd like to see this as a product you can buy, leave a comment.

New Cabinets = New Workshop

So we're having my friend Josh build custom cabinets for us. All we've got left is the doors to wait for. As soon as he's done, we'll be putting in wood floors, but so far I think things are looking good.
The real point here is that we had a bunch of old ugly cabinets waiting to be thrown out. But I decided to do what any self-respecting maker would do:


Monday, February 28, 2011

LegoShield Fabrication

I sent off the newest version of the LegoShield PCB to BatchPCB this weekend, so We'll be getting the first few pieces back in a couple of weeks. At that point, I'll assemble them and see if any distributors are interested in taking part.

I decided to use the official NXT RJ12 (modified phone jack) for the NXT connections, so now you can either plug in a mindsensors multiplexer or plug the device in directly to the shield.

As before, the shield is compatible with the Xbee shield for double-stacking.
Also, there's a blueSMIRF port now, so you can use sparkfun's bluetooth module instead of xbee if you so choose...

Should be interesting!

Monday, February 7, 2011

LegoShield Updates

Sean and I are currently working on improving our Lego Compatible Shield.
Here's an early look at the PCB.

This version will sport:
  • Voltage jumpers rather than switches. I noticed the switches I used on the last version were way underrrated.
  • Can type Capacitor for battery stabilization
  • NXT Header for connecting to the mindSensors NXT host cable. This will make it easy for anyone to connect their arduino to the NXT Sensors.
  • Reset Button Brought to top
  • 5V and 0V Rails next to the Analog In bank
  • BlueSmirf Header for Bluetooth Connectivity (not shown in photo)
  • Pulldown Resistor on the Enable Line
  • VRaw will be connected to external power (don't reverse the leads, folks!)
  • adjustments to the Lego Hole Sizes
Hopefully we'll be ready to send them off for fabrication soon!

Tuesday, January 25, 2011

Meccano is Great

Meccano/Erector is a great prototyping and one-off construction tool.
Here's a device sitting on my desk that I use almost every day.

The mount is resizeable so that any ipod case can slide in and out and be held in place only by friction. This allows me to quickly insert/remove the Ipod before I head home from work.
The back also has a vertical slider so that the viewing angle can be changed.

I enjoy the look of the newer, more industrial looking meccano pieces.