Introduction

I don’t know how many people want to make a spectrum light, but are struggling to find a reference circuit. Finally, they make a volume level light and claim it is a spectrum light.

In fact, it is not difficult to use hardware spectrum lights. It's nothing more than adding a bandpass filter to the level light.

working principle

Use a voltage follower to get the "zero voltage" point of the op amp. Pretend you are dual power.

The signal coupling of the microphone is near the "zero point" and amplified in the same phase ratio.

Divide into 6 band-pass filters with different frequencies and amplify. Center frequency f=1/(6.28·R8·C7), note that C6=C7, R8=R10, R9=2R8

Students who are interested in filtering can take a look at the " EDA Instrument Competition Question Guide ", which just talks about this infinite gain filter and parameter selection.

The "Long Range Infrared" project contains simulation schematics, and you can modify the parameters of the simulation to view the results.

Couple the AC signal directly to the level light module via capacitor.

Because there are 6 of the same circuit, one more component is 6 times more.

Therefore, the level indication uses the simplest LED + resistor combination, without using diodes to divide the voltage or a dedicated level light chip.

Function explanation

The potentiometer adjusts the gain. When the sound source is far away or the volume is low, the gain can be increased to obtain a better display effect.

In the video, lamp post 5 does not light up because of component welding damage. It will be repaired and uploaded later.

Component selection

Some people may think that these circuits are a bit extravagant compared to Taobao kits.

But in fact, if the quantity is large, placing orders yourself will not be much more valuable than Taobao.

As a soldering learning board, it is recommended to choose the cheapest electronic components. Can support domestic chips.

Because the component fails, the process of troubleshooting further tests whether you have a thorough grasp of the principles.

related suggestion

The potentiometers and chips between these circuits are universal. If a certain circuit is damaged, the east wall can be removed to repair the west wall.

Sorted from simple to difficult, teachers are welcome to use them in teaching, but we hope that the URL of this open source page will be added to the courseware to show respect, thank you.

Analog circuit

1. NE555 Ambilight RGB driver
2. LM358 infrared sensor faucet circuit
3. NE555 dormitory magic lamp driver circuit
4. LM358 running water breathing lamp
5. LM358 pickup delay circuit
6. LM358 refrigerator closing reminder circuit
7. LM358 steering gear tester circuit
8. NE555 steering gear tester circuit
9. Dual-way Wien bridge sine wave generating circuit
10. NE5532 infrared reflective switch plus bandpass filtering
11. NE5532 music spectrum light

power circuit

1. Transistor constant voltage and constant current linear power supply
2. MC34063 single inductor buck-boost power supply
3. MC34063 temperature controlled fan
4. MC34063 light control lighting
5. LM358 constant voltage and constant current power supply

Digital circuits

1. CD4017 music doorbell
2. 74LS00 builds JK flip-flop
3. CD4013 three-person answering machine
4. CD4017 running water lamp clock