Pedometer with Analog Display
I want to explore analog interfaces for smart wearables. My vision for this project is to produce wearable, that looks like superficially like a old-fashioned watch. The device will have a dial indicator that corresponds to the number of steps, increasing over the course of a day before resetting.
This will be an electro-mechanical device - it will still use digital components, however, the interface will not use an a digital display.
The core functionality will be driven by an acceleormeter and microcontroller, and converted into mechanical motion with a stepper motor and gearing system. There are surface mounted accelerometer module, such as the LIS2DS12 (opens in a new tab), with very low power requirements and that implement step counting functionality via interupts.
To start, I've been fabricating a Lavet stepper motor (opens in a new tab) -- the same mechanism used in quartz watches to convert electrical impulses into controlled mechanical motion. Normally, I would source this type of subsystem rather than building it myself, but I wasn't able to find any available online. (Based on tear-down videos of Swatch watches, my guess is that these motors are often tightly coupled to the manufacturing process and are built in-house.)
First, I created electromagnetic coils and used my power supply to characterize what current and voltage were required to influence a diametrically-megnetized (opens in a new tab) neodymium magnet.
Then I designed a mount for the coil in Fusion 360.