MASN V2.0: the Meshtastic solar node is now more resilient

MASN V2.0 is an evolution of the original MASN PCB, developed to improve the reliability of the Meshtastic solar node in real-world, long-term outdoor installations.

The first version of the project was focused on simplifying the assembly of an autonomous solar node by reducing wiring, integrating the main modules into a single PCB, and using components that are easy to solder. That version remains valid and continues to be the recommended option for users looking for a simple build based mainly on THT components.

Version 2.0 keeps the same general philosophy of the project, but introduces two important improvements: battery level reading from Meshtastic and a voltage supervision system to improve the node’s behavior when the battery is fully depleted.

These improvements address issues detected during real-world use of the board in autonomous solar nodes. In particular, work has focused on the system’s behavior when the battery is protected by the BMS and the solar panel begins to deliver voltage progressively as it receives the first hours of daylight.

Unlike the previous version, MASN V2.0 includes some SMD components. This makes it possible to add new functions without significantly increasing the size of the PCB, although it also makes assembly more difficult.

For this reason, MASN V1 remains the easiest version for getting started with the project, while MASN V2.0 is aimed at those looking for a more complete, more resilient board that is better prepared for remote or hard-to-access installations.

Changes compared to MASN V1

At the design level, MASN V2.0 keeps the general structure of the original board, but adds a small electronic stage intended to improve the node’s power management.

The main practical difference is that the new version no longer relies solely on the behavior of the microcontroller and the battery BMS during low-voltage situations. The board incorporates additional components to better handle those states and avoid incomplete startups.

The circuitry required for the battery voltage to be read directly by the NRF52 has also been added. This allows the Meshtastic app to display the node’s battery status in the device list.

Aspect	MASN V1	MASN V2.0
Assembly	THT components	THT + SMD
Difficulty	Easier	Moderate
Battery reading in Meshtastic	Not directly available	Added through a voltage divider
Low-voltage protection	Dependent on system behavior	Added through a voltage supervisor
Recommended use	First build, learning, testing	Outdoor or remote installations

Battery level reading in Meshtastic

One of the improvements introduced in MASN V2.0 is battery voltage reading from the NRF52 microcontroller.

To achieve this, a voltage divider has been added and connected to an analog input on the microcontroller. This circuit adapts the battery voltage to a safe range for the NRF52, allowing Meshtastic to interpret that value as the node’s battery information.

This improvement does not replace the telemetry provided by the INA3221. The INA3221 remains useful for checking voltages and currents in different parts of the system, such as the solar panel, the MPPT charger output, or the node’s power consumption.

The main difference is its integration within Meshtastic. With MASN V2.0, the battery level can be shown in the general node list of the application, alongside the other devices in the network.

This makes it easier to check the node’s status at a glance, especially when it is installed outdoors or in a hard-to-access location. It does not add a completely new measurement to the system, but it does make the battery information more visible and easier to check from Meshtastic’s usual interface.

Voltage supervisor and recovery after full discharge

During testing and real-world use of MASN V1, a specific behavior was detected in some nodes powered by battery and solar panel.

When the battery was fully discharged, the BMS cut off the output to protect it. In that state, the node shut down correctly. The problem could appear later, when the solar panel started receiving light and generated an initial voltage that was still too low to power the system reliably.

Under those conditions, the NRF52 could attempt to start before the power supply was adequate. This incomplete startup could leave the microcontroller in an unstable state, known as brownout, from which it would not always recover without a manual reset.

MASN V2.0 incorporates a voltage supervisor to avoid this scenario.

Its function is to keep the system disconnected while the voltage has not reached a safe level. When the power supply is back within the proper range, the node can perform a clean startup.

This modification is especially useful for the node’s behavior during real solar charging cycles, where voltage does not appear instantly, but progressively depending on available light, panel orientation, battery state, and environmental conditions.

The goal of this improvement is to reduce the possibility of a remote node becoming locked up after a deep battery discharge.

Available MASN V2.0 variants

MASN V2.0 is available in two variants, depending on the LoRa radio module used.

PCB variant	LoRa module
MASN Core1262 V2.0	Waveshare Core1262 HF
MASN HT-RA62 V2.0	HT-RA62

Both variants include the same MASN V2.0 improvements. The difference lies in the format and pinout of the LoRa module, so it is important to choose the correct PCB before ordering it.

Assembly considerations

MASN V2.0 keeps a similar assembly process to the previous version for most of the main components. The modules, connectors, push buttons, and switches are still placed directly on the PCB.

The main difference is the addition of several SMD components associated with the new battery reading and voltage supervision functions. These components require more precise soldering than the usual THT parts.

For this version, the following tools are recommended:

Tool	Recommended use
Soldering iron with a fine tip	Soldering small components
Flux	Improves SMD soldering quality
Precision tweezers	Placing resistors, capacitors, and the supervisor
Magnifying glass or simple microscope	Visual inspection of solder joints
Multimeter	Checking continuity and voltages before powering the board

Before connecting the battery or solar panel, it is advisable to inspect all SMD solder joints and check that there are no bridges between nearby pads. It is also recommended to verify continuity on the main power lines.

The assembly does not require advanced equipment, but it does require more attention than MASN V1. For this reason, this version is better suited for users who already have some soldering experience or who can get help during assembly.

If you do not want to solder the SMD components manually, you may consider ordering the PCB with those components already assembled by the manufacturer. This option simplifies the assembly process, although it increases the final cost of the order.

Bill of materials (BOM)

The electronics of MASN V2.0 are built from a series of modules and components detailed below.

Since some purchase links may stop working over time, reference photos of each component are also included. This makes it easier to identify them and search for them from other sellers if necessary.

You can install the PCB in any waterproof enclosure compatible with the size of the board, the battery, and the solar panel you plan to use.

MASN V2.0 components for the Core1262 module

Part	Qty.	Cost	Source	Notes
MASN V2.0 PCB for Core1262	1	€5	Download
Waveshare Core1262 HF LoRa module	1	€8.79	Aliexpress	Choose the 868 MHz version if you are in Europe

MASN V2.0 components for the HT-RA62 module

Part	Qty.	Cost	Source
MASN V2.0 PCB for HT-RA62	1	€5	Download
HT-RA62 LoRa module	1	€5.29	Aliexpress

Components shared by both variants

Ref	Part	Qty.	Cost	Source	Notes
	NiceNano (NRF52840)	1	3€	Aliexpress	Get the red PCB version
	Antenna Cable UFL to SMA	1	2€	Aliexpress	15 cm female version
	GrandWisdom 868 MHz Antenna	1	3,40€	Aliexpress	SMA male connector
	5V Solar Panel	1	6,89€	Aliexpress	Claims 35 W, but not real
	MPPT CN3791 Charger	1	2,20€	Aliexpress	Select the 6V version
	INA3221 Current Sensor	1	1,72€	Aliexpress	Buy the purple one, not the black
	BMP280 Temperature/Humidity Sensor	1	0,94€	Aliexpress	Choose 6-pin, 3.3 V version
	Li-ion Battery 4400 mAh / 3.7 V	1	10€	Aliexpress	With PH2.0 connector and BMS (Battery Management System)
	40-pin Straight Headers 2.54 mm	2	1,4€	Aliexpress
	40-pin 90° Headers 2.54 mm	1		Aliexpress
	2P JST PH 2.0 mm Battery Connector	1	1,62€	Aliexpress
	SS12D10 Switches	2	0,99€	Aliexpress
	2P Screw Terminals for Battery/Solar	2	1,80€	Aliexpress
R1, R2	SMD resistor 1 MΩ – 1206	2	4,59€	Aliexpress	Buy the 1206 kit; it includes several values.
U4	SMD voltage supervisor MCP1321T-29LE/OT – SOT-23	1	0,85€	TME
C1	SMD capacitor 100 nF – 1206	1	4,59€	Aliexpress	Buy the 1206 kit; it includes several values.
R4	SMD resistor 680 kΩ – 1206	1	0	Aliexpress	Already included in the previous kit.
R3	SMD resistor 200 Ω – 1206	1	0	Aliexpress	Already included in the previous kit.
Q1	SMD transistor AO3407A – SOT-23	1	0,85€	TME	Comes in a pack of 5 units.