If you do a lot of work on bicycles then a decent repair is very valuable. They can clamp onto various parts of the frame, like the top tube or seat tube, and support the bike while you work on it. Truing a wheel, for example, is much easier with a bike stand. And if your bike’s weight is an important factor, then Dane Kouttron’s Bike Repair Stand with Built-in Scale should be right up your alley.
The project’s title explains everything: this is a bike stand with an integrated digital scale. With a quick glance at the readout, a builder can see how much the bike weighs at any point during assembly (and deduce the weight of individual parts). It is meant to work with a wall-mounted bike repair stand. Kouttron built a base for the stand and the scale sits between the two, but it would be possible to adapt the design to keep it wall-mounted.
An Arduino Nano measures the weight of everything from the repair stand and out with a DYMH-103 strain gauge through an SEN-13879 amplifier. It receives power from an 18650 lithium battery cell via a battery charger/booster module. It then displays the weight on a small 16×2 character LCD connected through I2C. Tare is simple, since the weight of the bike repair stand doesn’t change and the Arduino can subtract that from the total weight to calculate the weight of the bike. The user can also push the “tare” button if they want to subtract the weight of a bike frame or other components.