Changes

I happened to notice the thermometer at home. This kind of thermometer aligns with my traditional understanding of what a thermometer should look like. However, modern manufacturers seem to lack creativity in their designs. They simply slap an LED screen onto a basic, square-shaped device, which looks quite dull and doesn't blend well with the home environment. Therefore, I thought about utilizing the classic appearance of a traditional thermometer, integrating some mechanical structures to display the temperature. By using synchronous belt gears to convey temperature changes, it could become a highlight within the household.

Structure:

To begin with, selecting the right materials is crucial. I was initially undecided between acrylic and basswood panels, unsure which would be more appropriate. However, after examining the interior design of several homes, it became clear that wood finishes are generally preferred. As a result, I've decided that using layered basswood would be the more suitable option.

In line with a more contemporary style, the wooden panels are also easier to process, facilitating subsequent procedures. For temperature display, I plan to use a mechanism similar to that of a 3D printer: employing a stepper motor to drive a timing belt, which in turn moves the pointer across the dial. This approach ensures the stability of the pointer and the accuracy of temperature indication. I had also considered using a lead screw and slide table for the drive mechanism, but ultimately abandoned this idea due to the high cost associated with lead screws and slide tables.

The next step involves choosing the motors and drive components. The commonly found 42 stepper motor is often used in robots and 3D printers due to its outstanding stability. However, its large size makes it impractical for use in thermometers. After thorough consideration, I decided to go with the 28BYJ48 geared stepper motor.

This stepper motor is compact in size and operates at low current, which can be driven by the [https://www.unikeyic.com/products/1003001012806686/ULN2003.html ULN2003] chip. It is also more affordable than the NEMA 17 stepper motor and comes with a reduction gear, ensuring adequate torque. The output shaft is a 5mm D-shaped shaft that is compatible with commonly available synchronous pulleys on the market. For the transmission system, standard components frequently used in 3D printers can be employed. I used a 16-tooth GT2 synchronous pulley as the driving wheel to drive the timing belt, while the driven wheel setup is quite simple, requiring only two bearings. This approach is both straightforward and cost-effective, eliminating the need to purchase idler pulleys. The tension of the timing belt determines the accuracy of the pointer's indication, so I added a tension spring to ensure the timing belt remains taut at all times.