Saturday, 18 February 2017

Some Assembly Required ...

I don't always get chance to publish every design I work on, mostly as time simply does not allow for me to get the data together. One design I did publish, coming up to 4 years ago has produced some interesting prints.
Minecraft Creeper - With Movable Head

The original intent of the Creeper design was to establish some design rules around spring clips and clearances; whilst engaging my kids in engineering design, production, sales & marketing. I also wanted to investigate how the home tool set I had available, would lend its self to reverse engineer an existing design and allow subsequent iteration into a customised version.

The reverse engineering led me to an early version of  Solverring's InStep (Now Rev 2), Meshlab (Dec 2016 update available), FreeCad (Now Rev 0.16) and of course Netfabb (now owned by Autodesk). I published the design supported with descriptions of the process and limitations. As I hadn't seen anything similar and the separation of the two body parts allowed an improvement in part quality, although with some if limited impact on print time and filament consumption over the parent.

With some absolutely gorgeous colours used to print a Minecraft Creeper, here are two of the more unusual Minecraft Creeper prints people have been kind enough to post about:

Coming in at 260 mm (10 Inches)! Needing "around 270g of filament. Print time was around 24/25 hours"
By Saij make:289112

Coming in at  37,5 mm (1.5 Inches)!
By konn4x4 make:296560

Thanks to everyone posting pictures, I really enjoy seeing what you have made.

Sunday, 23 October 2016

Arduino Sealed Case...

Arduino case (in the case shown for a Leonardo)

Arduino Case
An IP65 possibly to IP68 case for Arduino foot print PCB's

This is a bit of a tidy up post as I promised I would post these designs for the Greenpower project. There will be a follow up posts on the sensor cases and Arduino Mega case that we finally used, as well as the Raspberry Pi Web server case which links the vehicle telemetry to the clients web viewers used to monitor vehicle performance.

This unit was used in our Greenpower F24+ race car project (, as the prototype and test data logger. It is also used for general Arduino and PicAxe projects.
Sealing peas used for cable exist are AMP Supereal 1.5 peas Radio Spares ( RS Stock No. 314-1176 TE Connectivity Mfr. Part No. 281934-4 ( When fitting pea seals, ensure the holes are the correct sizes and lubricate with soap to permit insertion. Alternatively use your favourite silicone sealant in place of pea seals. To restrain the cable internally use a cable tie or similar.

This case ( without with the test USB access port ) has run in 4 races in the rain and been left out doors in a tool shed over the winter. When correctly printed the case is dust, spray and splash proof.

If you have poor or incorrect layer bonding or poor seam re-starts, consider spraying the case with a plastic filler or otherwise treating the surfaces for improved performance. As the volume of the interior is considerable there may be some minor pumping action through cables passing into the case if cable ends are not sealed.

The ends are printed separately to allow different features (sensors, indicators, switches cables etc) to be added or removed as necessary. Printing an additional slightly modified version of the centre section allows an Arduino Mega 256 to be housed using the same set of components.

Recommend stainless steel screws and nuts if the item is expected to get wet.
An elastomer bumper is included in the STL files which was used to protect the module ends. This optional item is not recommended where full sealing is required.

STEP files are included in a ZIP file to permit easier modification where needed
Note you should take your own steps to validate sealing integrity as printing quality can be so variable.