3D Printed Sensor EnclosureAugust 23, 2017

John Oliva

joliva63@gmail.com

Background

• I am building a home automation system and need sensor and actuator nodes

• Hardware and software is ready

• Need enclosure(s) for building nodes

Hardware

• Low power version of Arduino

Hardware (cont.)

• NRF24L01+ GFSK radio transceiver

Hardware (cont.)

Hardware (cont.)

Software

• Arduino library + MySensors

Sensor Node Components

• CPU/Radio board + Software ✔

• Sensor ✔

• Batteries + battery holder

• Enclosure

First Concept Sketch

• The design concept is a long narrow enclosure with compartments.

Batteries + Battery Holder

• Low power CPU/Radio runs off 2 AA batteries

• Design concept is long and narrow so AA batteries must sit end-to-end.

• Since I am looking to 3D print what I can, I will print the battery holder rather than purchase one

• Let me check what is available on Thingiverse for the battery holder.

Battery Holder

• https://www.thingiverse.com/thing:1755397

Battery Holder (cont.)

• Designed with OpenSCAD ✔• I have used this one before ✔• Design configuration only supports side-by-side for multi-

cell. Ruh Roh ✗• Wait a minute – I know OpenSCAD so I can modify the

design ✔

Battery Holder (cont.)

• Original side-by-side version in OpenSCAD

Battery Holder (cont.)

• Modified to support end-to-end + no flanges

Battery Holder (cont.)

• New + old capability via customizer

3D Printing Battery Holder

• Finally, its time to 3D print something

• Wait… I am using a new brand and color of PETG filament

• Better make sure I have the settings dialed in properly to get good, strong prints

3D Printing Battery Holder (cont.)

• Use a really simple object that will print fast to test the slicer settings

• Iterate and vary layer height, temperature, speed, etc.

3D Printing Battery Holder (cont.)

• Rate the results from various combinations to find the sweet spot.

3D Printing Battery Holder (cont.)

• Export STL for battery holder from OpenSCAD and import into Simplify3D (my slicer)

3D Printing Battery Holder (cont.)

• Generate GCODE using Simplify3D using sweet spot setting and print!

3D Printing Battery Holder (cont.)

• Some connectors that work with the design purchased on eBay

Sensor Node Components

• CPU/Radio board + Software ✔

• Sensor ✔

• Batteries + battery holder ✔

• Enclosure

More Concept Sketches

3D Printing Enclosure (cont.)

• Measure internal parts in order to design the enclosure

3D Printing Enclosure (cont.)

• Use OpenSCAD and customizer to design enclosures and insertable bottoms – this may take some time to get it right

3D Printing Enclosure (cont.)

3D Printing Enclosure (cont.)

• Design and print clip for connecting compartments

3D Printing Enclosure (cont.)

3D Printing Enclosure (cont.)

• Uh, oh. Too tight.

3D Printing Enclosure (cont.)

• Better

Sensor Node Components

• CPU/Radio board + Software ✔

• Sensor ✔

• Batteries + battery holder ✔

• Enclosure ✔

Assembly

• All parts printed and ready for assembly

Assembly (cont.)

• Battery, battery holder in compartment

Assembly (cont.)

• All components in compartments

Assembly (cont.)

• Fully assembled

Future Improvements

• Tune dimensions of battery holder and compartments for a better fit

• Add fillets to enclosure to strengthen places where walls meet

• Experiment with other enclosure configurations – not long and narrow