> **_If you enjoy this free newsletter,_** why not subscribe to Where's Your Ed At Premium? It's $7 a month or $70 a year, and helps support me putting out these giant free newsletters! * * * At the end of November, NVIDIA put out an internal memo (_that was_

At temporaerhaus, we have been playing with LoRa and LoRaWAN since 2016 – that is low-power, wide-area radio communications for sensors, both as infrastructure like TTN as well as the peer-to-peer Meshtastic system. Lately, a few of us have tinkered around finding matching spots for more TTN gateways, but also for Meshtastic nodes that increase the coverage of the system. Looking into Meshtastic started out as more of a side project, but since the nodes do not necessarily need Internet and constant power hookup, building _these_ nodes went over more quickly than getting new TTN gateways up and running. Additionally, I found that building a grid-independent Meshtastic node can be done even more cheaply than the usual instructions floating around at (mostly) YouTube – while those end up upward of 70 EUR per node with RAK-based transceivers, I got away with an even cheaper solution using a Faketec PCB build. I was able to build my nodes **for around 30 EUR per device** – by cheating a bit, because I had quite a lot of the parts already lying around and we were able to source dirt cheap surplus antennas. Realistically, you can build one such node at about 30–60 EUR, with antenna size and quality being mostly responsible for the 30 EUR leeway. A Faketec V3 PCB as ordered from JLPCB. -stk, FakeTec board back P1089951, CC BY-SA 4.0 The Faketecs are a community-developed PCB base plate in the form factor of the widely-used Heltec LoRa32 boards. The Heltecs can be sourced from Aliexpress etc. in the 15–25 EUR range per device, depending on availability and special offers. They come with a display and are… okay for first steps with the Meshtastic (or Meshcore) ecosystem. They come with WiFi and can be accessed through your local network instead of through a Bluetooth or serial connection, but due to them being based on a ESP32, they are rather power-hungry and the radio is just so-so, at least in the now-to-be-superseded V3 version. The Faketecs in their most basic form just connect a nRF52840-based microcontroller board to a HT-RA62 LoRa radio board. If you want the most basic imaginable build, you just solder these three parts together and you’re done. If you want, you can add a voltage divider to measure the battery voltage, the two buttons also used on the Heltecs (for resetting/setting the device into DFU mode for flashing, and navigating through the menu options) and a cheap OLED display to arrive at pretty much the functionality of the Heltec boards, sans WiFi connectivity. The boards have been expanded by community members to also include MOSFETs to drive an optional GPS receiver, buzzers, vibrating motors etc, and there is also a version around that even includes a MPTT charger for solar recharging. I stuck to the “basic” version – and I think this is still enough to build a solar node. ## What I used It’s not pretty and it does not use fancy 3d printed mounting options, but it works. -stk, 2025-10 Meshtastic Node temporaerhaus P1090100, CC BY-SA 4.0 To build one node (with options for many more to come) I used the following components: * 30 (yes) PCBs of the FakeTec v3 version ordered through JLPCB, about 4 EUR (about 15¢ each) * 1 Nice!Nano-clone, about 3 EUR from AliExpress * 5 HT-RA62, about 23 EUR from AliExpress (4,60 EUR each) * 5 IPEX to SMA pigtails, supposedly with RG178 cabling, about 3 EUR from AliExpress (60¢ each) * 2 SMD resistors for the voltage divider, spare parts lying around * SMA 868 MHz antenna for testing, spare part lying around This means that **a bare-bones Faketec node costs me about 8,35 EUR per pop** – or, more realistically, 45–50 EUR for five nodes, with leftover PCBs to give away to others. If you include the push-buttons and have to buy resistors, this will add another ~5 EUR to the total bill. In order to make this a solar node for outside, a couple of other parts were necessary: * 5 TP4056 charging boards with undervoltage protection, unter 2 EUR from AliExpress (about 40¢ each) – I had these lying around already; if you need to buy those anyway, you might want to use “proper” solar chargers instead (see below) * 1 6V 6W solar panel, surplus from “smart” bike lock experiments by radforschung, can be sourced new from AliExpress for about 12 EUR * 1 2×18650 (parallel) battery holder, about 1,30 EUR from AlIExpress * 2 spare 18650 batteries from leftover battery packs that had been lying around * Set of waterproof cable glands, ca 8 EUR, AliExpress * 1 waterproof junction box, f-tronic NFK08, 2,50–6 EUR * spare SMA to N-type adapter with a _really_ beefy coax cable that barely fit through a PG11 cable gland that was part of a collection of leftover Helium mining equipment sourced dirt-cheap through ebay * Fiberglass antenna with N-type connector from the same source The finished setup mounted on top of a roof. -stk, 2025-10 Meshtastic Node temporaerhaus P1090106, CC BY-SA 4.0 I have tried a couple of different junction boxes for the setup so far. The NFK08 can be bought at the local hardware store (Hornbach) in Germany off the shelf, albeit for about 6 EUR per piece. When shopping around or being able to source them through somebody bulk ordering material for electrical installations, they can be had for as little as 2,50 EUR. This box leaves just enough space for a two-cell 18650 battery holder, the Faketec node, the charging board and the necessary cabling. They feature membranes for the openings through which the solar connector can be poked through at the bottom. For real water-proof connections, the membranes can be cut out and M20 cable glands can be screwed into the existing threads. Another box I tried is the Wiska COMBI 407 which sold for 2,50 per pop for ages – their price shot up recently for whatever reason. The Wiska box has more space and is able to fit a three-cell 18650 holder. The solar cells were just laying around, but they can be ordered at Ali for about 12 EUR a piece. Due to their intended use for smart bike locks, they came with Julet M8 connectors, which fit my idea quite nicely – this way, I ended up with a water-proof connection outside the junction box. The panels are probably quite over-dimensioned for this type of task. I chose to under-engineer the charging circuit part and rather have a really beefy solar panel instead. Putting the antenna in front of the humble junction box. -stk, 2025-10 Meshtastic Node temporaerhaus P1090099, CC BY-SA 4.0 There are two ways to connect an antenna to such a box while still leaving everything rain-proof: Connecting the antenna to the top while ensuring everything is waterproof, or leading the cable out at the bottom in a loop. Some outdoor nodes I saw used N-type terminals at the top of the box onto which the antenna is directly screwed. The antennas I had available have a N-type _socket_ at their bottom instead of a _plug_. Apparently, this is rather unusual, and I could not find any fitting N-type _plug_ adapters that would have allowed mounting the antenna directly to the junction box. Fortunately, we had some 10cm adapter leads from SMA to N-type with _beefy_ cabling lying around that just fit through a PG13.5 cable gland. This allowed for a (hopefully) water-proof connection through one of the M20 mounting holes on top of the box. This makes the antenna the primary mounting point, with the junction box more or less dangling below it – it was fixed to the mounting pole with zip ties and that was it. Due to the lever the massive antenna has, this is most likely the smarter option. ## Charger considerations Not great, not terrible: The TP4056 with added battery protection. -stk, TP4056 board P1089956, CC BY-SA 4.0 Using a TP4056 board for solar charging is… controversial, and others might scold you for that idea and recommend you using “real” MPTT circuits like a CN3791 module and using its power path capabilities. I had the TP4056s already lying around with no other use for them, and I liked that they have the DW01 battery undervoltage IC onboard. The surplus 18650 cells I had left over came without any battery protection, and I’d rather have the charging boards functionality keeping the batteries from being sucked dry than optimizing for perfect charging conditions. For now, even though far from being optimal solar charging boards, the TP4056 boards appear to be doing their job. The first prototype had been lying with its solar panel behind a window with almost no direct line of sight to the sun at any time, and 42 days in with getting less and less light, the two 18650 cells are still not completely drained. The installation on the roof with direct sun exposure continues to be practically completely charged all the time, even now at the end of November. I will eventually go and replace the TP4056 boards with a “proper” solar charging setup, after adding battery protection features to the cells I used. For now, the setup works fine though – the Faketecs draw amazingly little power, even without any energy management optimization so far. I had initially planned for 4×18650 cells powering the node, but experimenting with the first prototype made it clear that even two cells might suffice. ## Things to watch out for when building your own * Make sure the NiceNano boards already have a bootloader installed _before_ soldering them to the PCB. The cheaper versions on Ali sometimes come without a bootloader installed, and while you can flash the bootloader _before_ soldering, if you find out _after_ soldering the controller to the PCB, you’re pretty much out of luck. * As with all RF boards, do not power up the Faketec without an antenna attached to the RF module * bring the 18650 cells to the same charge before connecting them in parallel * I have painstakingly avoided calling this solar node a “repeater” or anything like that. While, functionally, putting this thing up on a high rooftop makes it kind of an “extender” of a Meshtastic network, this is essentially not different from any other node taking part in the system. The role for the node should therefore be set to `CLIENT` and not `ROUTER` or `REPEATER`, unless it is positioned _really,**really**_ high up. Think not “on the top of a tall building”, but rather “the 120m tall silo that sits on top of one of the tallest hills overlooking pretty much everything around here”. * Do adapt the output power of your node to the antenna gain to stay within legally mandated limits. In Europe, the limit is at 27 dBm EIRP. ## So, how much is this node, in total? It all depends on how many nodes you will be building and what you’re already having lying around unused. Assuming you gang up with friends and build several nodes, a realistic guesstimate runs something like this: * 1 FakeTec node: About 8,50 EUR * 1 Junction box: 2,50–4 EUR * 1 18650 Battery holder: 1,20–2,50 EUR (depending on number of cells) * 1 TP4056 board with DW01: 40¢, or a CN3791 board: ~2,50 EUR * 1 Adapter cable from SMA to your antenna connector of choice: 2–8 EUR, depending on cable type and length * 1 Solar cell: ~12 EUR * 2–n 18650 cells: Source locally, prices vary _widely_ * 1 868 MHz antenna of your choice, with mounting option: Prices and quality also vary extremely widely here. Some supposed 868 MHz antennas are tuned to something between 850 and 920 MHz, with the sweet spots far away fom 868 MHz. Your mileage will vary – antenna know-how and access to a VNA pays off a lot. **Total: 27–37 EUR, plus battery, plus antenna** Realistically, depending on where and how you get your batteries and antenna, you might end up at about 30–60 EUR in total. That is quite a bandwidth – it depends mostly on whether you’re able to source your antennas and batteries cheaply and whether you have some of the stuff already lying around uselessly. Comparing this to the usual current howtos, the RAK WisBlock kits they use alone will set you back about 35–45 EUR – and that’s without any case, battery or solar panel. Don’t misunderstand me – if you want something that just works, go for e.g. the Seed Solar Node and be done with it. This build is interesting if you already have some of the parts and/or can source matching antennas with high gain. ## What is it with the 18650s? You can also use some “pillow style” LiIon batteries. I’d personally rather not buy new batteries for something like this, but rather look into pilfering worn-out laptop batteries and the like. That is just a personal choice.