The serial communication function is still to be developed. The current code will loop 30min enable / 2hrs disable power delivery by default. You'll need to edit and upload the .ino code by yourself to modify the duration.

A little USB addon that can switch VCC automatically by time based on CH552 or ATtiny85

With loopback output checking feature to detect if the MOSFET's breaking.

If the LED starts blinking, it means your MOSFET is likely failing and may completely die within 36 hours. This self-diagnostic feature was added based on some expensive lessons. Don't ask how I know. 💸

BOM:

Part name	Suggested Model	Amount	Notes
Board	CH552, ESP32C3 SuperMini or Digispark ATtiny85	1	It would be better if it comes with pin header.
Board Socket	CH552: DIP-20 IC socket or 1×10 female header ESP32C3 SuperMini: DIP-16 IC socket or 1×8 female header ATtiny85: 1×6 and 1×3 female header	IC socket: 1 Female header: 2 (each 1 for ATtiny85)	Prevent board wasting from wiring false or possible heat damaging
P-Channel MOSFET	AO3401	1	Toggling VCC
N-Channel MOSFET	To be decide Not always needed	1	ONLY needed if you're using a ESP32C3 SuperMini Shifting 3V3 logic to 5V in order to control PMOS
SMD-THT convert board	SOT-23 to DIP	1	Make AO3401 be able to use on a perfboard
MOSFET Connector	1×3 pin header	1	To connect AO3401 to perfboard I'm using 90° one, and the perfboard wiring is based on self-bended 90° pin header
Resistor	220Ω, 10kΩ	1, 1	1/4W. 220Ω for protection, 10kΩ for pull up.
USB convert board	USB Type-A Male and Female to DIP	1, 1	Buy a DIP ones for the best usability.
Button Switch	A simple button	1	I use a 2 pin one to make everything easier
Capacitor	0.1μF	1	Hardware debounce
Circuit board	Single sided Perfboard	1	3x7cm suggested, although I'm use the one I had in my hand.

MOSFET is to simulate the function of a relay.

If you're using ATtiny85, the time will be few minutes off per day, so if you really want make it turn on and off on accurate time, using other development boards like Arduino Nano, Micro or Raspberry Pi Pico, Zero etc. and make some change in the code would be suggested.

The way to start using CH552

This section is based on this tutorial (in Traditional Chinese) but Translated by me.

Add third-party board definition

Add https://raw.githubusercontent.com/DeqingSun/ch55xduino/ch55xduino/package_ch55xduino_mcs51_index.json to your Arduino board definition from Prefrence, and search for CH55x board in Board Manager

Install driver

1. Download Zadig

2. Press PROG or Download button before you connect your board to your computer

3. Connect your CH552 to your computer via USB cable WITH the button STILL be pressed

4. After the board appear as "undefined device" (不明裝置) in Device Manager (裝置管理員), release the button

   1. Open Zadig, choose Unknown Device 1, click Install Driver or Replace Driver

5. Wait for up to 3~5 minutes

6. Reconnect the board after it's done

7. There should be a COMX in your Device Manager (裝置管理員) (for example, COM7)

Flash bootloader

In Arduino IDE, Tool > Board > CH55x Boards > CH552 Board

Arduino should flash the correct bootloader when you upload your code. You can try writing a code to blink the onboard LED which is mostly on pin 30. Simply write digitalWrite(30, HIGH) can turn on the LED.

How should I determine what pin number should I write while using CH552?

If your board label your pin as something like 30 31 32, write the number as you see. The code in the last step is an example.

If your board label your pin as something like P3.0 P3.1 P3.2, ignore 'P' and '.', only write the number. For example:

Label	Pin number in Arduino	Label	Pin number in Arduino
P3.0	30	P1.1	11
P3.1	31	P1.3	13
P3.2	32	P2.0	20

The way to start using ESP32C3 SuperMini

The perfboard wiring picture is compatible with ESP32C3 SuperMini by offset the board placement lower a row.

Caution: You'll need to change the pin definition of the .ino code

Basically the same as an ESP32

The way to flash bootloader to an ATtiny85

Caution: the perfboard wiring picture is not compatible with ATtiny85 by offseting anything

You'll have to wire everything on your own according to the schematic. You'll need to change the pin definition of the .ino code, too.

Raw ATtiny85 IC

See this. You can use some USB converters like CH340 to use serial function.

I'll suggest you to add some female header / pin socket for pins that's needed for flashing, or find a way to solder your USB converter on your perfboard and connect to your ATtiny85, or take the IC from the device to your motherboard every time you want to flash your change.

ATtiny85 board with built-in USB, no matter if you're using the USB type-A one or Micro USB

The step here is basically tested in Arduino IDE v2 (2.3.6).

First, follow the instruction here, but when you move on to the last screenshot, which is just on the top of the "Wiring" section, please select the board to ATtiny85 (Micronucleus / DigiSpark), and the clock to 16MHz or 16.5MHz in order to use your ATtiny85 with your USB port.

For the programmer part, the modern version may no longer have Arduino as ISP (ATTinyCore) anymore, if so, select Arduino as ISP instead.

For wiring, let me add something here to complete the instruction:

Connect this pin on UNO / Nano	to this pin on your ATtiny85
D10	P5
D11	P0
D12	P1
D13	P2
5V	5V
GND	GND

Also, connect a 10μF capacitor between Reset (RST) pin and GND for Arduino. The long pin to Reset, the short pin to GND.

Now to the last step: click the Burn Bootloader button in Tools that's just below the Programmer selection.

You should now successfully burnt your Bootloader. If the board still doesn't work, that's because you haven't install the USB driver for ATtiny85. Unlike flashing bootloader, the tutorial of this is commonly spread on the internet. You can simply search that online.

TODOS IN THE FUTURE

To do recently

Upload perfboard wiring picture

Stage 1

Add serial communication and develop controlling app on Windows and Linux (maybe use Qt or some kind of webapp like ZMK Studio like this to make user able to custom their own schedule.

For example:
[1, 3, 1] = 1 on/off loop, on for 3 hours, off for 1 hour, loop
[3, 1, 3, 2, 4, 3, 5] = 3 on/off loop. On for 1 hour, off for 3 hour, on for 2 hours, off for 4 hours, on for 3 hours, off for 5 hours, loop

Needs to calculate the maximum of milis() function to estimate the suggested and theoretic max hour for a single on or off

Stage 2

Able to input minutes and hour decimal point (decimal point and hour can convert to minutes in controlling app, but need to see if the maximum minute (because variable type or processor bit) can handle the theoretic max hour)

Out of stage

Shorting two pins on the right to turn on light detecting mode. Have a photoresistor to detect if the lighting is over a threshold. If over a threshold, start the loop. If below a threshold, keep disable power delivery. The threshold can be set in real life by shorting another pin by clipper or wire.

This is the pin configure of the mode switching pin and threshold adjusting pin:

Pin:
A      B      C
|      |      |
mode   LOW    threshold toggle
swchŋ  consistent output

Soldering A-B together: enable the mode Touching B-C: record current analog input of the photoresistor pin

Rough codes about the analog pin:

uint8_t photoRth = 128;
void setup()
{
    // ...
    if(EEPROM.read(254) == 1) photoRth = EEPROM.read(255);
    // ...
}

void thresholdUpd(int Dpin, int Apin)
{
    if(digitalRead(Dpin) == LOW)
    {
        while(digitalRead(Dpin) == LOW);
        uint8_t rec = analogRead(Apin);
        if(rec == 255) rec--;
        EEPROM.record(rec, 255);
        EEPROM.record(1, 254); // checking byte to confirm the validation of the data
        photoRth = EEPROM.read(255);
    }
}

    if(analogRead(photoRpin) > photoRth)
    {
        // the loop code, but make sure start with enable power delivery
    }
    else
    {
        digitalWrite(gate, LOW);
        toggle = true; // disable power delivery and record current state
    }