Why We Built RAK11160: A Smarter Way to Bring ESP32 into Low-Power LoRaWAN® IoT
At RAK, we’re always listening to developers. And over the past year, one pattern became impossible to ignore. We noticed a strong trend: more than 60% of our customers buying RAK3172 were pairing it with an ESP32 module.
Why? To unlock WiFi and BLE capabilities. For MQTT forwarding. For OTA updates. For device provisioning. The ESP32 offered powerful tools for IoT, but it came with one major tradeoff: power consumption.
That’s when we asked:
Could we make this setup simpler?
And how could we use the LoRa ESP32 only when necessary to save power?
These questions led to the development of RAK11160.
The Problem
ESP32 + STM32 = Power Drain & Complexity
ESP32 is popular among developers for its WiFi, BLE, MQTT, and OTA capabilities, which simplify development. But it’s not inherently designed for ultra-low-power operations. Especially when paired with STM32WL for LoRaWAN, the dual-chip setup became costly and power-hungry if not carefully managed.
In battery-powered devices, even a few milliamps of leakage can reduce battery, sometimes cutting it from months to weeks.
Meanwhile, having two separate chips meant two firmwares, more components, and a bigger PCB footprint. For a lot of IoT designers, it became a pain point.
The Inspiration
What if ESP32 could sleep like a sensor?
We didn’t want to reinvent the ESP32. We just wanted to use it smarter.
So, we redesigned the architecture. Instead of keeping ESP32 powered continuously, we placed its power control under the STM32WL. The STM32WL became the "brain" that could power the ESP32 on or off by using a General Purpose Input/Output (GPIO) pin connected to the ESP32’s Enable (EN) pin.
When LoRa is all that's needed? ESP32 stays off, consuming as little as 1 μA. Need to push data to MQTT? STM32WL wakes ESP32, handles the transmission, then powers it back down.
Rather than two independently operating chips, this design involves one master controller (STM32WL) managing the power state of the other (ESP32).
The Solution
RAK11160 integrates the STM32WLE5 and ESP32-C2 microcontrollers into a single, compact module. This is the first in our product series to offer:
- A dual-MCU architecture built from the ground up for low-power IoT
- 3-in-1 connectivity: LoRaWAN + WiFi + BLE
- Direct EN pin control from STM32 → ESP32 for ultra-efficient sleep management
- Onboard memory for offline data logging
- A form factor compatible with existing WisBlock designs
Developers often ask, “Isn’t using ESP32 + STM32WL worse for low power?”
Not in our case. And here’s why:
- In RAK11160, the ESP32 doesn't stay powered all the time.
- We’ve designed a smart control setup: the STM32WL manages the ESP32’s EN pin directly.
- When low-power mode is needed, STM32 pulls a GPIO low, and the ESP32 goes into full power-off mode.
- (Spoiler: that’s just ~1 μA sleep current on the ESP32 side.)
This means when you’re just handling LoRaWAN packets, ESP32 consumes zero power. Only when you need WiFi or MQTT does it briefly wake up. That’s how we get long battery life, without sacrificing connectivity.
We will soon publish detailed power consumption test data.
What Makes RAK11160 ESP32 with LoRa Unique
Low power. Zero compromise. Here’s how RAK11160 rewrites the ESP32 playbook:
1. ESP32 Power-Off Architecture
The ESP32-C2 is completely powered off when inactive, a key difference from typical dual-MCU setups where both processors often stay powered. This leads to significant energy savings.
2. Smaller Design Footprint
No need to wire together two separate modules or write two independent firmwares. RAK11160 reduces complexity at every level.
3. Onboard Memory = No Data Loss
In environments with intermittent connectivity, STM32WL can log sensor data locally and forward it later via WiFi or LoRa.
4. Supports Rust Programming
Both STM32WL and ESP32-C2 are compatible with Rust, opening the door to safer, more modern IoT development for security-critical industries.
Real-World Use Cases
RAK11160 is designed for applications where power, connectivity, and flexibility matter:
Agriculture Monitoring
Log data in the field and sync it only once a day via WiFi to save battery.
Location-Based Asset Tracking
Use ESP32 to scan nearby BLE beacons, then sleep until the next cycle. It’s perfect for logistics and environmental monitoring.
Battery-Powered Single-Channel Gateways
Use STM32WL for LoRa forwarding while ESP32 handles setup or emergency MQTT push. No constant WiFi connection needed.
Smart City Infrastructure
Build compact devices like traffic sensors or lighting controllers with LoRa + WiFi/BLE in one module.
What’s Next?
We’re currently publishing detailed power consumption benchmarks so developers can see the benefits for themselves. Early tests show significant reductions in standby and active power draw compared to traditional ESP32-based solutions.
Whether you’re building an environmental sensor, portable tracker, or long-term agriculture deployment, RAK11160 is here to make your life easier (and your device last longer).
Want to dive deeper?