It wasn’t that long ago that projects with cellular connectivity were everywhere, but with 2G no longer universally available, glory days of cheap 2G modules seem to be on their way out. So when [Data Slayer] titled his video “You’ve Never Seen Cellular Like This” about a new GSM radio module, we couldn’t help but think that we have — and that we’re glad to see it back.
The module is the Walter, by DPTechnics out of Belgium. It’s fully open-source and contains a ESP32-S3 for WiFi and BLE plus a Sequans Monarch chip for GSM and GNSS connectivity. It’s not the blazing-fast 5G you’re paying your phone carrier for: this is an IoT modem, with LTE-M and NB-IoT. We’re talking speeds in the kbps, not Mbps– but we’re also talking very, very low power usage. Since it’s LTE-M rather than full LTE, you’re probably not going to be bringing back the golden days of Arduino Cellphones, (since LTE-M doesn’t support VoLTE) but if LoRa isn’t your jam, and you hang out around cell towers, this level of connectivity might interest you.
Walter is actually a drop-in replacement for PyCom’s old GPy module, so if you had a project in mind for that and are frustrated by it being EoL — well, here you are. [Data Slayer] seemed impressed enough with its capabilities as a GPS tracker. We’re impressed with the 9.8 µA consumed in deep sleep mode, and the fact that it has already been certified with the CE, FCC, IC, RCM and UKCA. Those certs mean you could go from prototype to product without getting tangled in red tape, assuming Walter is the only radio onboard.
Our thanks to [Keith Olson] for phoning in the tip. If you have a tip and want to connect, operators are standing by.
plenty of cheaper 4g options out there that will give you Mbps.
Some months ago I bought a chjeap SIMCOM LTE+GPS modem, and I paid about 10 bucks…
esp32 is not open source and have many blobs https://app.opencve.io/cve/?product=esp32&vendor=espressif https://nvd.nist.gov/vuln/detail/CVE-2025-27840 etc
not for me. this is not open source it is danderous!
Animal or human dander?
Careful, you don’t want to be accused of dander slander
The problem with LoRa is that you’re stuck using someone else’s gateway system to access data, and the transmission time limitations due to spectrum considerations are really cramping.
LTE-M gives you direct access from the edge to your server, because it’s directly on the internet, and you can send as much data as you please, limited only by how much battery you’re willing to burn. With near-universal 4G coverage even in rural areas now, there appears to be little use for LoRaWAN except for the simplest “smart meter” applications that only burp out a tiny bit of data once in a blue moon and don’t require two-way communications for anything.
Not in Australia there are plenty of places that don’t have coverage just outside of a populated centre. I live on a farm not more than 6km from a town and we have dead zones all over the place paddocks(fields). I like the idea of 4G but here I am setting up my own lots server and gateway to play with and put sensors all over the farm.
Auto correct messed with my writing lots server is ment to be loRa server