I would like to use OpenWRT to monitor temperature. One of the easiest solution would be to use 1wire with collectd and luci-app-statistics. 1wire is available on Raspberry Pie 2/3 and other appliances. It is also possible to use a USB 1wire adapter. So 1wire is very common and easy to implement. Temperature and hygrometric sensors are very cheap (around 2€ each) and as they are standard, they don't end up in a recycling trash as you can always use them within the next 20 years.
Would it be possible to package the Onewire plugin of collectd:
This package could prove very useful for OpenWRT users.
Thank you in advance and kind regards,