[Fede]’s other half utilizes a pair of digital calipers to take measurements of fruits, leaves, as well as stems as part of her field research. usually this means taking a measurement as well as composing it down in a log book. All things must be digitized, so [Fede] came up with a method to wirelessly log data off a pair of affordable Chinese calipers with a custom-made Bluetooth circuit.

Most of these affordable Chinese digital calipers already have a serial output, so [Fede] only needed to develop a circuit to take the serial output as well as dump it in to an off-the-shelf Bluetooth module. He fabbed a custom circuit board for this, as well as after seeing the increased battery drain from the Bluetooth module, decided to add an outside battery pack.

In addition to etching his own board for sending the serial output of the calipers to a Bluetooth module, [Fede] likewise put together a custom flex circuit to link the two boards. It’s just a little bit of brass glued to a transparency sheet etched with ferric chloride, however the end result looks amazingly expert for something whipped up in a house lab.