It starts immediately, and then every 5s thereafter. Maybe there's a way to tweak the registers for delayed start? I don't know. For now you might need to work around it. eg. [*] Simple: Create a variable to act as a 'first run' flag that is set on first run. [*] Slightly cleaner?: have a 'mini' pro...

Is it possible you're initialising a new http client (esp_http_client_init) for every request without a esp_http_client_cleanup? You can either create the esp_http_client_handle_t once and reuse the same one for every request, or create a new one every time and ensure its memory is freed afterwards ...

output_len is only being reset in the handler if the buffer is on the heap.
You could move the "output_len = 0;" lines in each of _FINISH and _DISCONNECTED so it's always reset.

The default behaviour is to run repeatedly, waking every 20ms in your case. You'll need to stop the timer like this: https://github.com/espressif/esp-iot-solution/blob/40cec135eace36cf11ab72988e27546a2c0d025b/examples/ulp_examples/ulp_adc/main/ulp/adc.S#L234-L237 Or if you only intend for it to run ...

Is it possible the ULP is running again (incrementing to 2) before the SOC has time to wake up and read the value? What is your ULP wakeup period?

esp_wifi_sta_get_ap_info?

https://docs.espressif.com/projects/esp ... p_record_t

Note the "NC". I'm not sure why though. Is it possible for someone to connect their own external flash, that might be 1.8V? Or maybe it's to future-proof the board layout in case of a Pico with 1.8V internal flash? Maybe the Pico D4 internal flash voltage wasn't finalised when this board was being d...

That's normal. It's a dev board, not optimised for ultra low power operation.

Turns out it was an incredibly noisy 12v DC adapter. Even plugging it in a few metres away made the touch sensor go wild. Values are very clear and smooth as soon as it is unplugged.

It's a dirt cheap one from eBay, I'll be replacing it one from a reputable brand and checking again.

"esp32/ulp.h"