更新记录

1. 5月29日 I started designing a schemati

   I started designing a schematic for a **UPS**. It took me a while to find the ideal circuit, but I finally came up with a very good **UPS** design. It has plenty of protection features and low power loss, and it can deliver up to **1.5A**. I’ll go into more detail and explain everything in my next journal entry once it’s completely finished. It’s already late in the night and I need to keep my streak going, so it’s not finished yet. ### Unfinished UPS schematic:  ### The entire schematic: 

2. 5月28日 I added connections for the

   I added connections for the **LED** backlight, but since I’ll likely be using a strip with **WS2812B** or similar **LEDs**, each one draws **60mA**. The main power supply can deliver up to **2A**; the **ESP** and all the sensors will draw about **1A–1.5A** (if everything is running at full power at once), which leaves **500mA** for the **LEDs**, so a maximum of 8 **LEDs**. It’s true that **60mA** is the current when the **LED** is running at **100%** brightness with a white color, but even so, it’s necessary to have a reserve. So I decided to add another power supply just for the **LEDs**, so they can draw up to **2A** separately from the main power circuit. This means that up to **4A** will have to come from the main connector input. So I simply added another **AP63205WU** circuit with a combined input with the other one, except there’s also a **100uF** capacitor for filtering spikes in case of a sudden high draw. I also added two switches to trigger an alarm in case the panel is pulled down or broken; they’re those lever-type switches, one between the box and the wall and the other between the front cover and the inside. I also added expansion pins and pins for potential wired communication directly from the **ESP**; one of them can also be analog. Now there’s just one thing left: the **UPS**, and maybe a few other minor things, and the schematic will be finished. ### The entire schematic: 

3. 5月27日 I added a door-open sensor and

   I added a door-open sensor and a room light sensor to control the display brightness. I also added a connection for the **mmWave Radar**, which is essentially a much better motion sensor because it can detect a person even when they’re not moving, and I can also know exactly where they are. I also added a passive buzzer for audio feedback and an alarm. I checked the schematic a little and thought about other things, and I realized that the original **3.3V** power supply wasn’t entirely suitable because it had a very low maximum current draw and would get very hot, so I replaced it with an **AP2114H-3.3TRG1**, which can deliver up to **1A**, has almost zero quiescent current, and is more efficient. I had to increase the size of the schematic from **A4** to **A3** because I had already filled it up completely and will be adding more components to ensure I have enough space. Finally, I added a pin expander because I’ll probably need more pins than the **ESP** has, so thanks to it, I have an additional **8 GPIO** pins. Next, I need to add a backlight and other things. I’ll save that explanation for the next journal. ### The entire schematic: