This is a wireless digital scale using ATTiny85 microcontroller and HM-10 Bluetooth low energy transmitter/receiver:
This scale is wireless. It may be useful where you can’t operate a normal scale, due to the weather outside, or if you don’t want to scare birds or other creatures away. With this scale you can weigh them. In this instructable, I used a 0 to 1 Kg load cell since I wanted to weigh hummingbirds and orioles that visited our nectar feeder.
Wireless digital scale – [Link]