Cheap alternative to buying two zigbee contact sensors for your mailbox?

Recently, I had an idea: What if, instead of buying two $20 Zigbee contact sensors, each using expensive button cell batteries, you bought a single $10 Zigbee remote using a single AAA battery and just soldered (normally open) reed switches to each button? That way, you could also place the remote on the back of the mailbox for better Zigbee range if needed. It even has a magnetic backplate, which would make it easy to mount and unmount inside or outside a mailbox.

So I bought and took apart the new $10 IKEA Rodret remote, as shown in the video below – and it looks ideal for the job! I don’t know if I want to complete the project myself since I already bought and modified two contact sensors that work well from inside the mailbox (based on two years of experience), but maybe someone else would find this worth pursuing? If so, please let me know how it goes.