Hermes External LoRA RAKWireless Solar Node Enclosure for MeshCore and Meshtastic

Hermes is a bespoke, 3D printed, easy to deploy external node enclosure for the RAKWireless 19007 and 19003 LoRA radio board. It enables you to deploy external nodes for MeshCore or Meshtastic (or others!) without the need to butcher a generic electronics enclosure with a glue gun, duck tape and burn your fingers soldering! It does this while not forcing you to sell a kidney to pay for it.

Stick it on a mast/pole. Stick it on a gutter. Stick it in a tree or a bush. Sit it on a windowsill. Hermes is designed to live in many places.

Like all of my designs, Hermes just requires you to add your board, batteries and antenna. You can also attach a common solar panel from a security camera or doorbell camera with the included cable and crimps.

Hermes features:

• Mounting positions for RAKWireless 19007 and 19003
• Mounting position for RAK GPS module RAK12500 ZOE-M8Q
• RAK Bluetooth Antenna recess to improve reception (I’ve had reception from 20-30ft)
• Support for either N-Type or SMA antenna’s
• 10cm “pigtail” for both antenna variants (the shorter the better reception)
• Weather resistant design made from PETG plastic with TPU seals
• Downward facing ports shielded from the elements
• A4 Marine grade Stainless Steel Hardware
• 4x 18650 Parallel battery holder
• PCB mounted hardware power switch
• Solar cable input hole enabling use of external solar panels
• Solar cable and crimps for easy use of common solar panels
• Access to USB port for 24/7 power or Extension cable for data access
• Multiple mounting options including pole mount and 7 cable tie points for stealth deployment
• Mounting position for VoltaicEnclosures PCM module (allows better low voltage protection)

Included with every Hermes are:

• Enclosure Body and base (N-Type or SMA)
• 2x TPU weather seals
• Power Switch PCB
• Parallel 4x 18650 battery holder with pre-attached JST connector
• Switch to RAK JST cable
• N-Type female pigtail/coax or SMA female pigtail/coax
• Rak Solar cable with push crimps to attach panel cable
• 4x Mini cable ties for cable management
• All A4 Stainless steel assembly hardware
• RAK mounting screws
• M2.5 Allen Key

No soldering is required and I include the Rak solar cable and two crimps that allow the solar cable to be spliced onto any common solar panel with just a pair of pliers. Simply cut the USB connector off any common security camera or doorbell solar panel and crimp the cable on!

Mounting Options Explained

For large pole mount antenna's the N-Type variant of Hermes can be attached be mounted directly to the antenna (as pictured)

For smaller N-Type antenna's that lack there own pole mount Hermes has an optional pole mount rear plate.

For SMA antenna's Hermes can be mounted to many things with just 9mm zip ties. If you wish to mount to a pole the optional pole mount rear plate can be used.

Design Decisions

If you study the many builds of external nodes that the talented LoRA community has made over the past few years you will realise you have many things to consider and a lot of decisions to make when building one.

If you take all factors into consideration and aim to mitigate every one of those factors…. you end up with an expensive box! (For example LTO batteries, custom charge controllers and hydrophobic vents) However what you also find are many people who have run much simpler designs for extended periods with no issues.

Hermes is modelled on the latter because for me LoRA is a hobby with a budget to match, thus my cases are aimed at the Hobbyist.

It does not aim to mitigate all the factors at play because it is trying to be as affordable as possible. It’s important therefore you consider it's limitations and how important they are to you, they are as follows:

• It is not fully sealed but is rain resistant (surviving sitting in my shower for 20 minutes and weeks up a mast in the north of the UK without issues) Condensation build up and dew should be minimal due to its compact design.
• It utilises 18650 cells which in theory won’t perform well in extreme temperatures.
• It utilises the RAK’s on board solar controller which is not as efficient as standalone MPPT controllers.

Mitigating these factors would have increased the cost of Hermes 3-4x times, that is not a product that interests me. If you’re happy with these limitations you’ll really like Hermes!

Hermes uses 4x the material and takes 3x longer to print than a Bender. If you compare the cost you’ll see it has not increased proportionally, I have done everything I can to make an affordable option for the community.

Assembly

Hermes is a semi-assembled kit. I pre-install the battery box, power switch and square nuts for you! You simply have to screw in the Rak board with the included screws, install your batteries and screw the enclosure shut with the included Allen key.

A full assembly video can be found at the link below showing the assembly of all Hermes components, the end user assembly is only the last few steps:

https://youtu.be/Iyay_YS18gg