boards

+[board link](https://www.electrodragon.com/product/smd-soldering-skills-training-board/)

+

+

+- [[training-board-dat]] - [[app-dat]]

+

+# Lucky-Wheel-dat

+

+

+

+

+## Description

+

+This kit arranges 10 LEDs in a circle. When you press the button, each LED lights up in sequence, spinning quickly at first and then gradually slowing down. Eventually, the spinning stops and one LED remains lit. If the final lit LED matches the player's prediction, it means "winning".

+

+You can assign numbers 1–10 to different items or tasks. The number corresponding to the final lit LED represents the selected item or task. This kit can also be used for guessing games, electronic dice, lottery machines, etc.

+

+## Working Principle

+

+The kit uses NE555 and CD4017 chips to randomly control the LED output. The control can be triggered by a button or a vibration switch. Simply press the button or shake the device, and the LEDs will start spinning. After a while, the spinning stops and only one LED remains lit.

+

+

+

+

+

+

+

+## ref

+

+- [[training-board-dat]]

+# christmas-tree-dat

+

+

+

+

+## Working Principle

+

+When powered by 3–5V, the 37 LEDs are divided into 4 groups. When the power is turned on, 4 transistors compete to turn on first. Due to component differences, only one transistor (let's assume Q1) turns on first:

+

+### Step-by-Step Operation

+

+1. **Q1 Turns On**

+ - LED group 1 lights up.

+ - Q1's collector voltage drops.

+ - The left side of capacitor C2 drops close to 0V.

+ - Capacitor voltage cannot change instantly, so Q2's base is also pulled near 0V.

+ - Q2 is off, and LED group 2 is off.

+

+2. **Q3 Turns On**

+ - Q2's high voltage passes through capacitor C3, raising Q3's collector voltage.

+ - Q3 quickly turns on, lighting up LED group 3.

+ - For a short time, both Q1 and Q3 collectors are low, so LED groups 1 and 3 are on, while group 2 is off.

+

+3. **Q2 Turns On**

+ - Power charges C2 through resistor R2, Q2's base voltage gradually rises.

+ - When Q2's base voltage exceeds 0.7V, Q2 turns on.

+ - Q2's collector voltage drops, and LED group 2 lights up.

+ - Q2's collector drop passes through C3, lowering Q3's base voltage.

+ - Q3 turns off, its collector voltage rises, and LED group 3 turns off.

+

+4. **Cycle Repeats**

+ - The circuit repeats this process, so the three groups of 18 LEDs light up in turn.

+ - At any moment, two groups are lit.

+ - The LEDs are arranged in a heart shape and flash in a flowing pattern for a dynamic display effect.

+

+

+## ref

+

+- [[app-dat]]

+

+# electronic-keyboard-dat

+

+

+## working principle

+

+- [[NE555-dat]]

+

+

+

+

+

+

+

+

+## ref

+

+- [[training-board-dat]]

+

+## basic toy version

+

+

+

+

+

+

+### Basic Operation Steps

+

+1. Turn on the power switch (rocker switch K1). The green LED will light up.

+2. Wait about 10–30 seconds. The blue LED will light up, indicating the charge is about halfway.

+3. Insert the projectile into the rear of the barrel. Press the fire button (round button K2) to launch the projectile.

+

+**Note:**

+- When the coilgun is fully charged, the red LED will light up. Because charging takes a long time and battery power decreases, the red LED may not light. If the blue LED is on, you can fire. **High voltage—danger**!

+- Before installing capacitors or if you need to re-solder during use, always discharge the capacitors first. Use a wire with plastic insulation, exposing copper at both ends. Hold the plastic part and touch both capacitor terminals with the copper ends to discharge. Otherwise, the capacitor may short-circuit and cause danger!

+

+

+

+### Main Technologies of Coilgun

+

+- **Power System:** Provides high-voltage power for strong electromagnetic force. Common systems include capacitors or battery packs.

+- **Electromagnetic Accelerator:** Accelerates the projectile using coils and supports. When current flows through the coil, a strong magnetic field is generated to accelerate the projectile.

+- **Control System:** Precisely controls the firing process, including trigger and speed monitoring.

+

+

+

+BOM list

+

+

+

+

+

+

+

+# metal-detector-dat

+

+

+## toy basic version

+

+

+

+

+

+

+### Debugging After Soldering

+

+- The inductors L1 and L2 are formed by copper traces on the PCB, so you do not need to make them yourself. This is simple and has a very high success rate!

+- The circuit uses only a dozen components. As long as everything is installed correctly, it should work normally.

+- After assembly, connect the power supply.

+- Adjust the potentiometer until there is no sound (when not near metal).

+- Bring the PCB antenna close to metal; it should make a sound. Move it away from metal; the sound should stop.

+- If the sound does not stop when moving away from metal, turn the potentiometer slightly counterclockwise and try again until it works as expected.

+

+### Common Issues

+

+- If it keeps sounding after powering on, the oscillator stage may not be working. Possible causes:

+ - Incorrect placement of resistors, transistors, or other components.

+ - Short circuit or open circuit in the PCB coil. Check carefully with a magnifying glass.

+ - If Q2’s amplification is too low, Q3 cannot turn off, which also causes continuous sound.

+

+

+## ref

+

+- [[training-board-dat]] - [[app-dat]]

+

+# radio-toy-dat

+

+使用STC15W芯片作为主控芯片，应用RDA5807S收音模块，具有87-108MHz全球FM接收频段相容的效果，具备噪音消除、软静音、低音增强、灵敏度高、噪音小、抗干扰能力强等优点。功放部分采用TDA2822功率放大集成电路，具有电路简单，音质好，电压范围宽等特点。

+支持双电源供电（USB5V供电或者2节5号电池供电）*注：供电方式二选一

+输出功率：0.5W喇叭：1/2W8R喇叭

+供电电压：5V/3V（双电源）频率范围：87-108MHz

+

+# training-board-dat

+

+- [[Lucky-Wheel-dat]]

+

+- [[electronic-keyboard-dat]]

+

+- [[metal-detector-dat]]

+

+- [[christmas-tree-dat]]

+

+- [[coilgun-dat]]

+

+- [[PPB0021-dat]]

+

+- [[radio-toy-dat]]

+

+

+

+## ref

+

+- [[app-dat]]