TL;DR version: I got to borrow the littlebits synth kit, and created a parametric version of the mounting board. The source files are available on github: https://github.com/osbock/Baldwisdom/tree/master/LittleBitsMounts

The Newton Free Library applied for and got a cool LSTA ( Federal Library Services and Technology Act) Grant to do a bunch of STEM related programs, and I have the honor of doing a bunch of coding and robotics workshops there over the next few months.

They got a bunch of cool new equipment to run these programs including Finch Robots, Arduinos (Sparkfun Inventors Kits), a KIBO robot, and … wait for it… a bunch of Littlebits sets. NFL Assitant Director Jill Grabowski was kind enough to lend me the coolest littlebits set: The Korg Synth kit.

If you aren’t familiar, they are modular electronics blocks that snap together with magnets. Unlike earlier “electronics construction sets” these are pretty foolproof, well thought out modules instead of just individual components. As Founder Ayah Bdeir says ,

AT LITTLEBITS, WE ARE ON A MISSION TO DEMOCRATIZE HARDWARE BY EMPOWERING EVERYONE TO CREATE INVENTIONS, LARGE AND SMALL, WITH OUR PLATFORM OF EASY-TO-USE ELECTRONIC BUILDING BLOCKS.

Unfortunately the thing that makes Littlebits easy is also it’s greatest weakness: The magnetic connection system.

Especially when making something you have to manipulate (like a musical instrument), they tend to come apart, you lose power, etc.

Now some of the other (more expensive) sets come with mounting plates (that you can also buy separately. I didn’t have one though, but I do have a laser cutter and a 3D printer. How hard could it be? Well, the devil is in the details.

First I looked to see if it was already done. Thingiverse (I know boo….) has a few designs, including some by littlebits themselves, mostly specific component mounts.

Rex Brodie posted this cool clip that fastens adjacent modules together.

It works pretty well (very solid) but it was difficult to put the two bits in without pulling and pushing and putting a bit of strain on the boards. (Especially scary when the ‘bits are on loan).

I tried just measuring and cutting holes with my laser, or a simple model with Open SCAD but I just couldn’t get the spacing quite right.

Thingiverse user Kris Kitchen had posted this design:

which I printed and actually worked quite well. Only problem was, it was an STL (Surface Tessellation Layer) file, and thus not easily modifiable. I wanted wider, arbitrary shapes, etc!

I could however pull Kris’s design into OpenSCAD, and do a trick to measure the “holes” and spacing.

This little bit of code:
[code]
projection(cut=false)difference(){
translate([0,0,-41])import(“LittlbitsGridthin.stl”);
translate([0,0,-10])cube([250,40,10]);
}
[/code]
cuts off the bottom so the holes will show and projects the outline in 2D.

I then exported this as a DXF file, and used inkscape to make measurements.

If I haven’t lost you by now, the part you are waiting for, the measurements (which I couldn’t find anywhere after much googling!)

• Holes: 6 mm diameter
• Spacing (edge to edge or center to center): 6.63mm
• spacing is also 10.5% of hole
• 1.294mm knockout line

The percentage bit is important (I calculated it, 6.63/6) if you are designing in inkscape because that is how you do a grid of evenly spaced objects.

I made a couple of attempts at a laser cut version, but it was very brittle, and I didn’t take into account the laser’s kerf (width of cut)

The 3D printed version came out pretty well, but the holes were a bit too small, so I enlarged them by .2mm (.1mm on the radius). and it worked perfectly!

Now we can make mounting boards in any shape!

The source files are available on github: https://github.com/osbock/Baldwisdom/tree/master/LittleBitsMounts

While it’s true that I love geeky new toys, I’m not typically an early adopter, preferring to wait until the bugs are worked out. Several of my neighbors got the first generation 3Doodler, and since it first came out, there have been many imitators. I backed the 3Doodler 2.0 kickstarter, and it arrived when I was away visiting family.

Impressions

It was a little annoying that it came via DHL with signature required. I managed to circumvent that via their website though, and it was nice to know ahead of time that I had a package coming.

The new pen is Much Much sleeker and very pleasant to hold. I don’t have much experience with the first edition, but my impression was that it was clunky and it’s plastic case made me hesitate about spending $100 for an educational toy. The new design was a good part of what pushed me over the edge, and the metal case feels much more professional, and the mechanics seem to work really well. It comes with a little screwdriver to adjust the temperature, as well as a wrench to remove the nozzle and a cool spring thing to push through any unextruded plastic when changing colors.

Patience!

My 14 year old daughter initially almost threw it across the room in frustration. I think it was mainly a matter of expectations, as it does take a little while (after heating up) for a newly loaded strand to reach the nozzle. I also initially thought parchment paper (being heat resistant) would be good to doodle on, but it was a terrible choice as the plastic wouldn’t stick to it.

Doodling surface

We tried several other things, and eventually hit upon several good surfaces. It’s important not to doodle on a really cold surface (as our stone countertops are this time of the year in Boston) as the plastic shrinks quickly and comes unstuck. Some scrap acrylic worked really well, as did plain paper.

Once we had things humming along, Charlotte tried again and instantly did the cute baby dragon in the photo above. While it’s not a fast process, its quite meditative.

 3D vs 2D construction and materials

It comes with a nice variety of materials, 2 packs of PLA, 2 Packs of ABS and one pack of flexible filament. If you want to doodle in the air and make 3D objects in place, your only choice really is ABS as it hardens quickly. It would probably also benefit from a desk fan to speed up the process. You can do some vertical stuff with PLA by doodling upside down and let gravity hold things straight for you.

Another option is to doodle 2 dimensional parts and then tack them together with the pen. 3Doodler has a number of fun templates on their website that you can print out, doodle over then peel off and tack together. I did their classic Eiffel Tower.

The first thing you’ll notice is that if you want precision, and a clean aesthetic, you should just get yourself a 3D printer. That said the drippy organic look has it’s own charm.

The second thing you’ll notice is that I made it from Pink PLA, and there certainly wasn’t enough of one color in the packs to do the whole thing. I’m fortunate to have a 3D printer that uses the same diameter (3mm) filament, so I cut some lengths of PLA. Because filament comes on a spool, the radius of the segments turned out to be a problem, causing it to not feed well. Holding the curvey segments over the stove burner (probably not recommended, a hair dryer would be a better choice). and rolling them straight on the counter made quite usable sticks that fed perfectly. There are two tools which are handy (and not included). One is a pair of tweezers to safely remove plastic from the outside of the nozzle,  and a pair of cutters to trim the melty part off the end of a filament you’ve backed out when changing colors.  They recommend you trim the end when reusing filament, but I managed to get the original sticks to feed in fine with little melty blobs on the end, but YMMV.

Accessories

I was already exceeding my budget to buy the pen, so I didn’t opt for any of the accessories, though I was sorely tempted. They offer a nozzle pack (including cool ribbony flat nozzles) and a battery pack for portable doodling. There’s also a foot pedal, whIch would relieve some of the stress of pushing the button (but I got pretty good at freehanding in the continuous extrusion mode…)

One other really cool thing they did for their kickstarter was to offer education packs that gave a good price with a generous helping of accessories for educational institutions.

Conclusion

I think the 3Doodler 2.0 is a well engineered and fun gadget. I’m planning on getting together with my neighbors and we’ll compare with the first version, as well as get more kid reaction, but in general I think it’s a great creativity inspiring tool.