Trident – A Rak Wireless LoRa Radio with Full SMA Breakout and swappable 18650 Battery for Meshtastic and Rnode

The Trident was designed for the Polymaker X Thingiverse Print The Practical Fiberon Functional Design Challenge in March 2025. This design challenge inspired me to leverage the strength of Fiberon PA6-CF20 in creating a beautiful and tough outer shell for this project. Designing this model took over a week in Fusion, and on sketchpads. After countless hours tweaking dimensions and printing seeming endless revisions, the result is a rugged enclosure with a great aesthetic- made even better by the use of my Fiberon filament!

This LoRa radio chassis is designed for the RAKwireless WisBlock 19007 with RAK 4631 Core. This model is challenging and rewarding- most configurations require soldering, general electrical knowledge, firmware flashing, etc. Tolerances on this print are tight with assembly gaps dialed in at 0.25mm. Know any potential limitations of your filament and printer before attempting.

Trident features a trio of SMA antenna mounts for LoRa (915MHz,) Bluetooth (2.4GHz,) and GLONASS GPS (~1575 MHz.) This allows the maximum potential of this radio kit in a handheld setting, while also allowing for quick adaptation to a mobile base station with a high-gain outdoor antenna setup. Additionally, there are options for the included RAK PCB antennas if you just want to get this up and running quickly.

Fairly compact at 74mm Width, 32mm Depth, 105mm Height without antennas. Though being the smallest or lightest was never the intention- I wanted to build the most rugged and versatile printed case for this radio platform.

The battery is a standard 18650, used in many flashlights and other off the shelf gadgets. I developed a printed screw cap mechanism to make battery swaps in the field easy. It’s a great feature to be able to quickly swap a battery on a hike or camping trip without needing to charge. This setup doesn’t interfere with the USB-C port, and USB charging also works great!

Trident has 4 outer shell designs- one showcases the Trident emblem and the other is a plain-backed variant. Each of these contains two sub-variants consisting of non-screen and OLED options. One of my demo prints has the venerable Fiberon logo debossed, though I will be retaining this file for personal use (unless otherwise allowed) as it contains a logo which I do not own.

The OLED is protected by an inexpensive 30mm watch crystal embedded in a printed bezel. There are frame options for either heat-set inserts (M2&M3,) or direct screw-into-plastic if you so choose. A truncated outer shell for open frame testing while assembled is included, as well as a charging base which routes a USB-C cable to the board.

.STL, .STEP and a Fusion file are included. All .STLs were exported in proper print orientation.

Easy to follow printing and assembly PDF is also included, and I may create a video assembly tutorial if the need arises.

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PARTS

REQUIRED! RAK Wireless 19007 Wisblock Module with 4631 Core:
https://amzn.to/3Fz6bZn

RAK Wireless RAK12500 GNSS GPS Location Module:
https://amzn.to/43RycFu

I selected this fantastic Muzi Works 915MHz LoRa antenna, but any 915MHz will work:
https://amzn.to/4kBxiDi

Some great little stubby 2.4GHz antennas to manage the Bluetooth, again anything in this range will work:
https://amzn.to/4kwzEmP

Most easy to find GPS antenna are in the 150-ishMHz area and are typically meant for marine applications, pet tracking etc. These will NOT work with the RAK GPS module. You need to find a ~1575MHz antenna such as this GLONASS/GPS Antenna I chose:
https://amzn.to/4iWN2yR

A note on antenna choices and compatibility- in this project I used SMA female to U.FL/IPX/MHF1 bulkhead connectors that wire to the IPX connections on the RAK modules. This decision means all antennas I used are SMA male. You are free to chose any size-compatible connectors you want, but be aware of the differences between male and female SMA and RP-SMA to make smarter choices when purchasing components.

SMA Female to IPX through-mount connectors.. These are obscenely high quality for the price:
https://amzn.to/4iXJsEC

RAK Wireless OLED Display, though any adjustable slot-mount 128x64 I2C OLED will do:
https://amzn.to/4iNp9tO

If using an OLED, a 30mm quartz watch crystal is used, though you could opt to purchase a slightly more expensive sapphire glass for more scratch resistance and strength:
https://amzn.to/4iY103u

20 Gauge Silicone Wire is required for the battery contacts:
https://amzn.to/3DOgHve
Thinner wire may be used if desired to wire to the OLED Display

Also for the battery contacts, two 6x10mm compression springs are used. Wire thickness between 0.5-0.8mm is recommended.
https://amzn.to/3FBzdaJ

To connect the battery contacts to the 19007’s included battery terminal, a JST-PH2.0 2-Pin connector is required.

If you plan on using heat-set inserts for the M2 screws, six 3mm⌀x3mm inserts like these are needed:
https://amzn.to/4iBydlw
Additionally two M3 heat-sets up to 8mm in length are needed.

When choosing not to use heat-sets, the two M3 that mount the frame to the shell are replaced by two M3 nuts which are glued into the Core Frame.

Both the heat-set and screw-into-plastic frames require six M2x6mm screws and two M3x16mm.

Two printed components (the Interior Battery Contact and the Frame Base) are glued to the Core Frame. The 30mm crystal and printed Glass Ring are also glued in place on the Outer Shell. Ensure you have a strong non-conductive adhesive such as cyanoacrylate or epoxy. I’ve had great results with BSI CA and JB Weld epoxy on this project.

Recommended parts include polyimide tape to isolate soldered contacts, quality soldering flux, and a decent 18650 charger such as a NiteCore. The batteries themselves are also important- quality 18650s typically reach about 3000Mah. Many sellers online advertise 9900Mah, but this is almost impossible with modern battery chemistry in this size. When in doubt, stick to reputable brands like Samsung and Panasonic. An o-ring for the tailcap is purely optional for improved retention. Anything 23-25mm OD, 1-1.5mm thick should stretch fine.

Finally, the filaments I used in making this project a reality:
Polymaker Fiberon PA6-CF20
https://us.polymaker.com/products/fiberon-pa6-cf20?aff=1186&utm_source=affiliately&utm_campaign=aff

Polymaker Polylite ABS Purple
https://us.polymaker.com/products/polylite-abs?variant=39574342500409&aff=1186&utm_source=affiliately&utm_campaign=aff

And my all-time favorite filament- Polymaker PolyMax PLA in FDE:
https://us.polymaker.com/products/polymax-pla?variant=40558463680569&aff=1186&utm_source=affiliately&utm_campaign=aff

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www.paypal.me/OptimalObjects