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…
What was the exact model? Im looking for something similar for the project
AND Technologies BK-A7970 board with SIMCOM A7670E SoM…
Which sorcific model did u use? Im looking for a cheap lte modem for the project. A7670SA?
a link to the product maybe,pls?
SIM7600G-H R2 is pretty good. Nearly global band LTE, UMTS and GSM for ~30$. I advice against LTE-M and NB-IoT modules, unless you know coverage in your target area is good.
Yep …. if you’ve got 4G coverage, go with that and not the Walter etc. Coverage for LTE-M is much worse than 4G where I live with whole towns in complete darkness. Also, although I dont know how Hologram works, I’d always want my data going straight to a relational database on my own (rented) server where it can then be processed directly into anything you want.
Do you know one that can make a call to send a fixed WAV file? I’m looking to make an alarm that can SMS me and also call me and play a menu WAV, than pass through PCM from the mic.
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
No more rhyming! I mean it!
CVE is an answer
Anybody want a peanut?
If you don’t need the wifi/bluetooth you can run it blobless. Some people made an open source wifi MAC implementation that is blobless after calibration, and somewhat usable depending on what you want. Bluetooth requires the factory blob, but fortunately other chips with open ble exist.
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.
Try a yagi for your antenna.
You’d probably be surprised – LTE-M/NB-IoT is much lower bandwidth than standard 4G, so it gets better range. Of course, it still depends entirely on Telstra. blows a loud raspberry at them
Lora is definitely a far, far better fit for your use case anyway – NB-IoT/LTE-M requires an appropriate plan and SIM cards from the carrier, and they really only cater to large-scale commercial deployments. Good luck getting Telstra to talk to you if you’re not a corporate entity, and they’re awful to deal with even if you are. repeated loud raspberry
Auto correct messed with my writing lots server is ment to be loRa server