Cheap and simple LoRa Node for schoolproject


(Realrob) #1

Hi all,
Vienna based I would like to introduce LoRa to my 20 !non-tech! students with an hands on approach to build some LoRa Nodes. To stay mobile with the possibilty of (solar?) recharging I found the WEMOS D1 mini Pro which now has an charger circuit onboard. For the LoRa breakout a friend who supports the project found this PCB https://github.com/hallard/WeMos-Lora . Maybe some of you allready tried this PCB? Or maybe you know a better or similiar board to work with? And also I would look for a source to manifacture the small pcb`s? Thanks in advance


(Ud Lo Ra) #2

Lora32U4, everything inside, or ESP32+SX127x (Heltec/TTGO).


#3

Remko is building 'educational nodes ’


(Amedee) #4

I also like the TTGO LoRa32, the small display is quite nice for this kind of projects, and the ESP32 gives you WiFi/BlueTooth as well


(LoRaTracker) #5

Unless you are absolutly sure the board of choice has a built in cut off to prevent over discharge of the LiPo, and most do not, best to avoid such boards in my view, especially in your circumstances.

Some LiPos do have built in cutoff circuits, but this is often at the 2.4V point, which is very low and I would need a lot of reasurance is safe.


#6

that seems a bit of a contradiction to me but ok… question is, are the students capable of connecting wires to a module, connecting a usb-serial interface to program, connecting a sensor ect.


#7

The Heltec Wifi LoRa 32 V2 (note the V2) has the advantage that DIO0 and DIO1 are already connected, so no additional wiring is required.

The antenna of most of these boards is connected via a u.FL connector with u.FL to SMA cable and a ‘loose’ antenna.
For non-tech students a board with SMA connector to which the antenna can be directly mounted will be more fool-proof (non-tech-proof) however.
Another option is to use a simple wire-antenna. This is cheap and is always mounted, without fiddling with U.FL connectors and cables. But many (all?) of the common ESP32 LoRa + display boards do not support a wire antenna.


(Realrob) #8

Hi all, thank you so much for your hints.
Hope thats ok to post aliexpress links:
I found 2 variants. What would you recommend to take?
1.) https://de.aliexpress.com/item/2-st-cke-von-TTGO-LORA32-868-915-mhz-SX1276-ESP32-Oled-display-Bluetooth-WIFI-Lora/32841743946.html?spm=a2g0x.search0204.3.116.48dd497ekkIMYF&transAbTest=ae803_4&ws_ab_test=searchweb0_0%2Csearchweb201602_3_10065_10068_10547_319_317_10548_10696_10084_453_10083_454_10618_10304_10307_10820_10821_537_10302_536_10902_10059_10884_10887_321_322_10103%2Csearchweb201603_70%2CppcSwitch_0&algo_pvid=c4efc296-136c-4b50-85ca-382a218fd700&algo_expid=c4efc296-136c-4b50-85ca-382a218fd700-16

2.) https://de.aliexpress.com/item/2-ST-CKE-433-MHZ-SX1278-ESP32-LoRa-0-96-Zoll-Blau-Oled-display-Bluetooth-WIFI/32838494945.html?spm=a2g0x.search0204.3.50.1f71346bhYloMd&transAbTest=ae803_4&ws_ab_test=searchweb0_0%2Csearchweb201602_3_10065_10068_10547_319_317_10548_10696_10084_453_10083_454_10618_10304_10307_10820_10821_537_10302_536_10902_10059_10884_10887_321_322_10103%2Csearchweb201603_70%2CppcSwitch_0&algo_pvid=35874fdd-cf81-4775-afbc-09462be5fbf7&algo_expid=35874fdd-cf81-4775-afbc-09462be5fbf7-7

best yours rob


(Remko) #9

For my educational nodes I selected a “simple” microprocessor like AVR processor that has good Arduino support and a Microchip rn2483 LoRaWAN module that has embedded stack. This is the Things Uno in my case who has antenna embedded. On top goes a custom made board.
The reason is that I want to eleminate risks and have the higest successrate.
I want to focus in class on my learning objectives and not on debugging nodes and lorawan stacks.

I would select non of them for my purpose.


(LoRaTracker) #10

I would agree.

Those u.fl connected antennas are just about acceptable when used in a cased unit, but as is they wont last 5 minutes in a classroom environment.


(Realrob) #11

Hmm okay. So the Module is not optimal for education. Yes thats excactly what i need are 10 nodes that transmit sensor data or even just a switch to give them a raw idea what possibilities LoRa can offer. Ideas for concrete hardware more than welcome.


(Maxious) #12

Taking into account the requirements for sensors, sma antennas and solar charging, might I suggest the RAK5202 tracking board https://www.aliexpress.com/store/product/WisTrio-LoRa-Tracker-RAK5205-is-built-on-SX1276-LoRaWAN-modem-with-low-power-micro-controller-STM32L1/2805180_32957226407.html?spm=2114.12010612.8148356.37.64c74461nRU17f&spm=a2g1y.12024536.slider_12822973.2

It has an acceleration sensor, temperature sensor, battery monitoring and of course GPS. The stock factory firmware will upload this data via TTN to the Cayenne website for visualisation http://docs.rakwireless.com/en/LoRa/WisTrio-LoRa-RAK5205/Application_Notes/RAK5205_Application_Note_V1.2.pdf


(Remko) #13

I propose Things Uno. compact, complete and good library support. also good availability.


#14

This repository contains a firmware for WeMos-Lora Node


(Mrpackethead) #16

I would look for something that is ardunio based, because its going to be SO much simpler for them to get something going. I’d then look for somethign that runs on simple AA batterys, and is robustly built, ( particually thinging about antennas )…


(Vldbzh) #17

Whisper Node
You could sold a battery holder for CR2032 and SMA antenna connector to them and pack that in a small box. This will give idea about mobility and compactness of LoRa.
One of nodes could be a base which receives messages from others.


(Jens) #18

Hello

NucleonBaseNode : https://forum.iot-usergroup.de/t/nucleonbasenode328-arduino-328-pro-mini-lora-gehaeuse-antenne/287

Round about 20€

Greetings


(Steve J Barker) #19

Hi realrob,
The Pycom LoPy4 might be a good choice as well. Program in micropython, a version of the python scripting language which is easy to pick up, runs via a REPL prompt, has Lora wan (+wifi and other networks) on board and I found it good to get up and going with as well. Lots of open source software out there to support configuration and if you need help there will be lots of us out there with examples and reference code. I am even deploying a number of these to real industrial applications using an on premise lora network, I have found them to be that reliable and robust. Cheers.


(Tvloon) #20

Hi RR,

You could go for an introduction that is proven to be a good option here in the birth place of the TTN … and
go for a basic PCB that has no real room for making any mistakes while building and flashing …
More info is in this … ref ; A first Lo-ra … MU


(M2mlorawan) #21

I prefer this Arduino Pro Mini with RFM95.