Water Resistant Mesh Node with RAK Wisblock and 18650

About

This is a case for a RAK19003 baseboard and a RAK4630. Designed to be water resistant with minimal openings and a screw in lid with a TPU gasket (actual waterproofness may vary). Powered by an 18650 battery.

RAK19007 should fit as well, but I don't have one to test.

Includes a lanyard hole on the top for hanging it up or attaching to a backpack.

Note: No GPS module and antenna support yet, there are reports of the RAK wisblock being unable to turn off GPS modules resulting in poor battery life. 

Overview

• Outer case (2 versions)

  • cyl case: Slide in nut version

  • cyl case inserts: Heat set insert version for use with 3.2mm OD M2 inserts (untested)

• Cap

  • cap: screw in lid

• Inner bulkhead

  • inner bulkhead: the plate behind the cap, holds all of the electronics together

• Wisblock brackets (3 versions)

  • 19003 bracket: Easy to print, no cutouts for sensors

  • 19003 bracket with sensors: Needs supports, has cutouts for both sensor slots on the back. More fragile than the one with no cutouts.

  • 19007 bracket: For use with the larger 19007 baseboard (untested)

• Battery holder

  • Battery holder: Holds an 18650 battery and the Bluetooth antenna

• O-ring

  • oring: Goes between lid and cap to improve water resistance. Print in TPU

• Reset button

  • rst button: the reset button which goes into the inner bulkhead

Parts used

• RAKwireless WisBlock Mini Meshtastic Starter Kit

  • I used: https://www.amazon.com/dp/B0DFMMTQZM

• 18650 battery with JST-PH 2 pin connector and protection module.

  • I used: https://www.amazon.com/dp/B0DK4BZB2J

    • I contacted the seller and they claim that these are from either PKCell or A&S Power which are decently reputable brands. The one that I got was from PKCell and seems to be working fine after around a month of use.

    • Alternatively, you can make your own 18650 pack with a better battery, PCM, and a JST connector if you have the tools to do so.

• SMA-Male antenna

  • I used: https://www.amazon.com/dp/B0D7D6866W

  • Get one with the appropriate frequency for your region.

• 7x M2 Socket head screws (6mm)

• 7x M2 Nuts

• Sensor safe RTV Silicone

  • For sealing the SMA connector. Use one which is safe for electronics (no acid fumes).

  • I used: https://www.amazon.com/dp/B0002UEOPA

• Superglue to secure M2 nuts. (Do not need if using heat set inserts)

• Optional: RAK1901 Temperature and Humidity Sensor

  • I used: https://store.rokland.com/collections/rakwireless-products/products/rak-wireless-rak1901-temperature-and-humidity-sensor-sensirion-shtc3-pid-100001

  • This is for monitoring the inside of the node for water intrusion and not for measuring external temperature and humidity.

Printing

• All parts are pre-oriented for best results

• Use high wall counts and higher temps for increased waterproofing

• Only the 19003 bracket with sensors needs supports

• All other parts do not need supports

• Print at 0.16 layer height for a nicer surface finish.

• I used TPU for the o-ring and glass fiber PETG for the rest of the parts.

Assembly

1. Secure RAK Wisblock to the Wisblock bracket with included screws

   1. Attach any sensor modules if you are using the version with sensor module cutouts

2. Slide 18650 battery into its holder and secure with thin string through the holes or tape

   1. IMPORTANT: Inspect the battery's JST connector to see if the wires are swapped.

   2. See: https://store.rokland.com/blogs/news/rak-meshtastic-starter-kit-battery-polarity

3. Attach the included Bluetooth antenna to the flat rectangular spot the battery holder

4. Insert M2 nuts into their spots on the wisblock bracket and battery holder

5. Place the reset button in its hole in the bulkhead

6. Secure the wisblock bracket and the battery holder into the inner bulkhead

7. Connect the Bluetooth antenna cable to the connector on the wisblock and tuck it in between the battery and wisblock.

8. Route battery wires to the power connector

   1. Do not plug it in yet, doing so may damage the radio

9. Apply RTV silicone around the included SMA to UFL pigtail. (See image)

10. Carefully lower the SMA connector into its hole in the top of the case.

11. Secure the SMA connector with included nut.

12. Clear out the sacrificial layer in the M2 nut slots in the case and slide in the M2 nuts. (secure with superglue for best results)

    1. Or insert the heat set inserts for the heat set insert version

13. Orient the battery and wisblock assembly so that the LORA ufl connector on the wisblock is on the corner of the case with the SMA connector

14. Partially insert the battery and wisblock assembly into the case until the SMA pigtail can reach the LORA connector on the wisblock

15. Plug in the SMA pigtail to the LORA connector. See image below. (Can be tricky, might need tweezers or small fingers)

16. Screw antenna into the SMA port on the top

17. Plug the JST-PH battery connector into the port on the wisblock

18. Slide the bulkhead into the case and secure with screws

    1. Do not over-torque if you are using the slide in nut version, the small M2 nuts may start spinning in their slots.

19. Place O-ring into its groove on the cap

20. Screw lid in to complete the build