[Solicitation Order] Portable Clock

### Introduction: #### A portable time management master powered by ESP-C3; it can help you manage your time more conveniently; the display part uses an overseas purchased [LCD screen] (https:// www.digikey.cn/zh/products/detail/lumex-opto-components-inc/LCD-S401C71TR/469785); driven by HT1621B### Circuit introduction#### Charging part##### Comparison adopted The cheap TC4054 chip adjusts the charging current to about 100mA and can be fully charged in four hours; ![01.png] ##### At the same time, in order to facilitate charging, a dual power supply switching circuit is also added![02.png] #### # IO usage #### Since both DS1302 and HT1621 use three-wire drivers, they occupy more IO. However, due to different enabling conditions, IO can be reused; ![1302.png] ##### DS1302 Operation timing! [1621.png] ##### Operation timing of HT1621; #### As shown in the figure above, reading and writing DS1302 need to pull the enable pin high; when operating HT1621, you need to pull the enable pin low It can be pinned, so you can share a set of pins, read and write DS1302 when it is pulled high; operate HT1621 when it is pulled low (when drawing the board, I was worried that it would not be usable, so I separated it, but it is completely possible to use Dupont wire to verify); ![Pin.png] ### Function implementation#### Button usage##### In order to realize the functions of adjusting time and recording time, a total of 4 interrupt buttons are used here, which are respectively defined as function selection, digital Four functions: plus, digital minus and default keys; ![Button.png] #### Reminder##### A buzzer has been added, which can be used as a reminder![buz.png] ### Actual object![ 20211209_165153.jpg] #### Back![20211209_165121.jpg] #### The main body, partitions and panels, and the back are still on the way, but it’s harmless, you can take a look at the preview! [Back 1.png] ### # The back of the back panel is made into a heating plate, which can be used to ~~heat your hands~~warm your hands in winter! [20211209_165310.jpg] #### Assembled finished product