My current setup consists of an Arduino Uno and a micro SD card. The Arduino gathers around 125 bytes of data every second. Currently, I store this data on an SD card. After a while (can be minutes up to 2 hours), the Arduino stops its data collection and sends the SD card data via BLE to a custom Android app and removes the SD file.
That means I need around 1mb of (temp) storage.
I'm trying to miniaturize my project and wondered what would be the smallest option of storing this temporary information on the device. I thought of storing it in SRAM, but I don't think an AVR chip exists with that much SRAM. I also thought of using an ARM chip like the nRF52840 (which has BLE support and 256 KB SRAM), but I can't find any information on how to use this chip in a 'custom Arduino'; I'd rather use AVR.
I'm also thinking about wear and have a couple of SD cards die on me, so I don't know which storage option has the most read and write cycles. This isn't the most important thing though.
I look forward to reading your suggestions.
Thanks in advance,