I've made a couple of minor changes to the BeagleBone enclosure kit. First off, they're now available in clear for those who want to admire at their little embedded computer but also keep it in a nice, safe plastic shell.
Next, I've modified the SD card slot to make it easier to insert and remove the SD card and accommodate the changes to the SD slot changes made in the A4 revision.
Finally, I switched to smaller diameter standoffs to avoid potentially hitting R150 on the bottom of the boards.
If you happened to be an early adopter, send me an email (craig@built-to-spec.com) and I'll get you some new standoffs and a new SD card panel!
In other news I've created a new page where you can find all the instructions for the various kits I offer that will hopefully be updating more frequently in the coming weeks.
After the move to the new location the big CNC router started acting up. The problem was eventually tracked down to the Y axis lead screw acquiring a slight bend in the move. Thanks to the efforts of Dave Dalton and Luis Rodriguez (thanks guys!), the lead screw has been replaced and the router is up and churning out parts again. Luis and Nick Woods have been cutting stools for the big room:
The Mehls cut the parts for a Link cosplay sword:
And I cut out the mounts for the R3's hold down rails and the blank for its sacrificial top:
Hopefully we'll be seeing more member projects rolling off the router soon!
I've been a bit busy lately and mainly working on other people's projects, so I haven't had a lot to post lately, but I have been working on the R3 (RepRap Router) again. My laser-strap prototype has taken up residence in the new CNC room at Hamerspace and is now sporting new endstops and tool mounts including a boom for its powerful little flex shaft spindle. I got in a quick test of the tool mount and spindle last meeting and grabbed some video:
Here's some additional pics:
Next on my list of stuff I need to do for this prototype is to get the hold down system in place and mill the sacrificial top flat. I plan on embedding some extruded aluminum T-slot that works with 1/4" hex bots into the MDF work surface like the bigger CNC setup at the space and using standard woodworking hold down clamps for now and maybe design some milled or 3D printed ones as the project progresses.
I got to play around with a borrowed BeagleBone board to get some kernel stuff working for a friend. While playing around with it I decided to throw together an and a for the thing as well. The sled is pretty easy to figure out, but the enclosure takes a little more effort to put together, so I thought I'd do a quick write up outlining how to assemble it.
First off, peel the masking off all your laser cut parts.
Next, you'll mount the BeagleBone to the bottom using 14mm M3 bolts, M3 nuts, and 1/4" OD 1/4" high nylon standoffs. Make sure to mind the resistors on the back side of the board around the power connect (labeled R150 and R189).
Next, you need to partially thread all the remaining M3x14 bolts into the T-slots of the spanning pieces and the end caps. This is physically possible without assistance, but it's hard. You'll want to save yourself some time by using some scotch tape and securing the nuts in place before inserting the bolts.
Once this is done, you can slide in the bottom, sides, and top before finally tightening down the bolts. Don't overtighten the blots, the enclosure is all acrylic and it will crack under extreme stress.
Bottom Installed
Sides Installed
Top Installed and Bolts Tightened
Other Side After Assembly
You can simply leave the top off if you want easy access to the expansion headers. The will even fit with the top off:
Here are some additional pictures of the enclosure with the USB host and peripheral interfaces plugged in (notice that you can see the status LEDs above the peripheral connection):
Grab an including handy hex wrench from my store and you can grab all the design files and BOM from the .
You can grab a there as well, if you feel like your BeagleBone would like a little more of an open air prototyping environment. You can find the design files for the sled, BOM, and instructions on its Thingiverse entry .
Here's a pic of a quick little dongle I threw together that allows you to power up a PC power supply and use it as a bench supply, or in my case, to power a few stepper controllers for my CNC setup. You can also use the dongle to test potentially bad ATX power supplies.
You can find tutorials on using ATX power supplies outside of PCs all over the net but all of them are pretty much a variant of what I have here. To get the thing up and running, you just need to:
Connect the green wire on the 20 or 24 pin connector to ground to power on the supply.
You'll probably want to supply a load to the supply to keep it up and running, usually just a power resistor on the 5V rail, a 10 Ohm 10W resistor is typically used, creating a 2.5W load. I've also seen people simply plug in an old PC peripheral like a hard drive to the supply to provide this load as well.
Attach an LED to the output of the supply OK signal to get a nice "everything's fine" light.
Here's what you'll need:
30 Ohm 5W Resistor - Mouser P/N: - This puts a nice 0.83W load on the 5V rail. Don't worry if this warms up a little bit during operation, that's what a resistive load does. This smaller load seems to work fine for me.
20-Pin Power Supply Connector - Mouser P/N: - Just the socket we need to connect to the ATX supply where a standard motherboard would be connected.
330 Ohm 1/4W Resistor - Just a current limiting resistor, not needed if you don't put a power on light on your dongle.
Green LED - Just a typical LED for your power good light.
Here's a couple close up shots of the dongle on the inside:
Check out the Wikipedia entry for and scroll down to the power supply section for a detailed pinout of the ATX connector. Note that I'm using a 20-pin connector and the connector pin numbers on the Wikipedia article are for a 24-pin. I'm using the pin numbers from the article, so realize they could be different based on which connector's pinout you're looking up, so pay attention to the actual signal names!
Basically I've connected pin 16 (power on) to pin 15 (ground), put a 30 Ohm resistor across pin 21 (+5V) and 19 (ground), making sure that the long exposed lead is connected to ground, and connected the positive lead of my indicator LED through a 330 Ohm resistor (hidden in the heat shrink) to pin 8 (power good) and the negative lead to pin 7 (ground). After testing, I wrapped the whole thing in a little electrical tape and installed it. I'm using the switch on the back of the power supply as my power switch, but if you want to have a more convenient switch wired to your dongle, just replace the jumper between ground an power on with a standard normally open switch.
