Why is my pico wifi connection dropping under load?

That jumping connection is almost certainly related to how the Pico manages the network stack under heavy load. If you are using MicroPython for this type of continuous, high-frequency data logging, especially involving HTTPS, you're likely hitting a resource bottleneck. While the Pico W is tiny and low power, it is fundamentally designed differently than the Raspberry Pi 4; the Pi runs a full Linux OS with dedicated memory and CPU power just to manage its own background processes, making sustained data transmission very robust. When you push a microcontroller to handle cloud API calls and continuous network traffic without that underlying OS buffer, things get jittery.

To get reliable uptime with a Pico, you really need to handle the network stack at a lower level. MicroPython might abstract things away, but that abstraction often doesn't scale well when multiple devices or heavy data loads are involved. Many people who have successfully replaced a full single-board computer on similar projects end up moving to C++ and managing the network protocol directly. This gives you full control over memory and allows you to tune the underlying TLS implementation, like mbedTLS, for maximum efficiency.

One reason MicroPython often struggles with high-performance networking is that the garbage collection and interpretation overhead interferes with the network buffer handling. If your logging routine is triggering large memory allocations or takes too long to complete, the network driver gets stalled, causing those frequent drops and connection resets you're seeing. Moving to C++ lets you preallocate all necessary buffers and handle the network lifecycle much more predictably.

If you don't want to rewrite everything in C++, you should look into libraries specifically designed for robust IoT connectivity that run efficiently on the RP2040 chip, minimizing the time the network stack spends in an unmanaged state. Simply sending bursts of data via MicroPython is often the wrong approach; managing the connection lifecycle carefully is what guarantees stability.

One thing I'd check before rewriting anything: keep a rolling log of gc.mem_free() right before and after each upload. If the number keeps shrinking cycle after cycle you have fragmentation rather than some deep flaw, and simply reusing one request object instead of building a fresh one every time, plus a gc.collect() just before connecting, sorted out a similar problem for me. Also a pedantic aside, the onboard LED on the Pico W is wired to the wireless chip itself, so if your code blinks it every loop you are pushing extra commands through the same chip that is trying to hold the connection steady.

I've been looking into this for my own smart home setup and I'm hitting similar issues. I'm using a Pico W to manage a few sensors in my garage, but when I try to add more than two inputs to the device, it just stalls. I was wondering if the problem might be the limited memory available for the internal buffer during the network transfer. Does anyone have experiance with a strategy for distributing those sensor tasks across a few different chips instead of relying on one single unit?

I've seen this play out before when folks swap out stable machines for these tiny chips. The thing is, the Pi has a full OS running all the time, so it doesn't really 'sleep' between network requests. It just sits there waiting for traffic. When you use a Pico W, you are running a microcontroller that might be cycling power or entering deep sleep modes to save juice. If your logging routine triggers a wake cycle right when the connection is trying to push data, you're going to lose the session every time.

You need to make sure the network keeps the connection alive even when the processor is chilling. Maybe you're not triggering the upload often enough or you're letting the wireless radio go dormant between your brief bursts of data. Try keeping the network stack constantly active even if the sensor reading is just sitting in a buffer til the right moment.

I struggled with connection drops myself before I figured out the issue wasn't the code but the network setup. My Pico started dropping Wi-Fi when running the log, even though my main router seemed fine. What fixed it for me was assigning the device a static IP address and setting a long DHCP lease time for it. It stopped struggling to maintain the connection. If you are hitting drops when you push the upload trigger, try locking the Pico into a permanent address instead of letting it borrow one dynamically.