Rostock MAX Training Class!

There will be a class for Rostock MAX machine operation real soon now!

This class will teach users the basics of machine operation, including:

  • Slicing a model
  • Starting up the machine
  • Changing filament
  • Printing
  • Finishing a print
  • Shutting down the machine
  • Troubleshooting and error recovery

Need to Test Some LEDs?

I’ve been buying some 3W LEDs from various sources for a project.  Each of those sellers makes wildly improbable claims about the brightness and chromaticity of their LEDs, but I didn’t have a good way to verify them and see which are best.  I found a light meter in the i3 Detroit eLab, but getting consistent readings from that was difficult.  The readings depend upon ambient lighting, angle to the LED’s axis, distance from the emitter, etc.  I finally came up with an idea for a (relatively quick) little jig to get consistent readings which at least allow me to compare LEDs to each other.  As a bonus, the materials are very cheap and it’s easy to build.

Complete LED tester

Complete LED tester

LED mounted on the base of the jig.

LED mounted on the base of the jig.

The LED is mounted under a piece of shim stock cut to form electrodes.  The electrodes can either contact the pads on the heatsink, or the leads on the LED itself.

This is the view from the end where the light meter probe fits into the laser-cut opening.  Because no problem worth solving cannot be solved with a laser cutter.

The interior of the chamber is painted with flat black paint to reduce the effects of any light leakage at the joints and reflections from the walls due to angle of view of the LED.

View of LED from the business end of the jig

View of LED from the business end of the jig

This jig is easy to connect to a current-limiting power supply, and it blocks out ambient light well (the meter reads 0 lux with the power off).  What it does not do well is provide removal of heat from the LED’s heatsink.  So it’s important to run the LED at a current level that does not generate a lot of heat, possibly wrecking the chip.  I used 600 mA for an LED rated at 700 mA and wavelength of 660 nm.  Blue LEDs generate more heat, so they would have to be tested at an even lower power level.  But the point here is to compare LEDs within the same lot or between lots, not to get calibrated readings that can be compared to standards.  That would require a much more expensive meter.

Why buy all these LEDs?  I’ll save that for a future post.


Yuri’s Night Celebration 2015

Yuri’s Night celebrates the first manned space flight. i3Detroit is hosting a Yuri’s Night event on Saturday April 11th starting at 5PM, open to the public. Come to i3 and join the celebration. We will have demonstrations of planetary dynamics, observation of the night sky, water rocket launches, space themed refreshments, videos, and games!

Mike Kirkhart, our feature guest speaker, is giving a talk about the $50 Satellite Eagle 2. We’re going to have DIY rocket fuel, liquid nitrogen ice cream, and more!


Click on the Read More link to get a ticket.

Read more

Spring PotLock this Saturday. March 21st, noon – 6pm.

New here? What the heck is a potlock?

It’s an i3 tradition, “potluck” because folks bring food, and “lock-in” suggesting an all-night party. Although lately we’ve realized that all-afternoon works better. (Having an official tools-down, pat-each-other-on-the-back time is important.)

It’s also the best way for new members (and non-members) to get more involved and connected! Because a lot of members will be around at once, but NOT debating policy, it’s as socially useful as a meeting, but we actually get physical things done. Potlock is a perfect opportunity to work alongside a bunch of other members, learn where things are and where things go, take some ownership of your favorite zone, and make the space better for yourself and others.

What’s the task-list this time around?

Potlocks traditionally center around the ToDo list in the wiki:

Being that this potlock is scheduled for the second day of spring this potlock will likely focus around the things we neglected to do over winter because it was cold out.

How can I help?

Show up and be your awesome self! Seriously, that’s it.

You could also sign up to bring some delicious food here:

Want more details?

Members can find discussion on the private list here: