In this project Mark demonstrates how to construct a spectrum analyzer using Lego bricks and discrete electronics. He provides building plans, schematics, and software source code to allow viewers to build their own versions. The device includes an analog front-end with bandpass filters, a preamplifier, an audio line input with a digital switch, a microcontroller, and a multiplexer for selecting different inputs.
Mark demonstrates the process of soldering the small components and assembles the board, which includes the ESP32 microcontroller and potentiometers for adjustment. He then shows how to put the board in the housing and add the necessary electronics, including LED strips and a microphone input, to complete the spectrum analyzer.
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Bonus Content:
Bill of Material:
| Product Name | Manufacturer | Quantity | Buy Kit |
|---|---|---|---|
| ALPS ALPINE Rotary Potentiometer, 10 kohm, 1 Turns, Logarithmic, 50 mW, ± 20%, RK09K Series | RK09D1130C2P | 3 | Buy Now |
| MULTICOMP PRO SMD Chip Resistor, 180 ohm, ± 1%, 250 mW, 0805 [2012 Metric], Thick Film, High Power | 0805W8F1800T5E | 1 | Buy Now |
| MULTICOMP PRO SMD Chip Resistor, 2.7 kohm, ± 1%, 250 mW, 0805 [2012 Metric], Thick Film, High Power | 0805W8F2701T5E | 1 | Buy Now |
| MULTICOMP PRO SMD Chip Resistor, 5.6 kohm, ± 1%, 250 mW, 0805 [2012 Metric], Thick Film, High Power | 0805W8F5601T5E | 2 | Buy Now |
| MULTICOMP PRO Small Signal Diode, Single, 100 V, 150 mA, 2.5 V, 4 ns, 500 mA | LL4148 | 10 | Buy Now |
| TDK SMD Multilayer Ceramic Capacitor, 2.2 µF, 50 V, 0805 [2012 Metric], ± 10%, X7R, C Series | 0805F225M500NT | 2 | Buy Now |
| PANASONIC CAP, ALU ELEC, AEC-Q200, 470UF, RAD CAN | VZH471M1CTR-0810 | 4 | Buy Now |
| MULTICOMP PRO SMD Multilayer Ceramic Capacitor, 33 pF, 50 V, 0805 [2012 Metric], ± 5%, C0G / NP0, MC Series | CL21C330JBANNNC | 1 | Buy Now |
| OMRON SWITCH, SPNO, 0.05A, 24V, THT, 0.98N | TC-1102-C-J-B | 2 | Buy Now |
| STMICROELECTRONICS Fast / Ultrafast Diode, 200 V, 4 A, Single, 1.05 V, 30 ns, 70 A | ES5JB | 2 | Buy Now |
| MOLEX Wire-To-Board Connector, KK 5045 Series, Through Hole, Header, 2, 2.5 mm, Tin Plated Contacts RoHS Compliant: Yes | 22041021 | 1 | Buy Now |
| MOLEX Wire-To-Board Connector, Vertical, KK 5045 Series, Through Hole, Header, 3, 2.5 mm RoHS Compliant: Yes | 22041031 | 1 | Buy Now |
| MOLEX Wire-To-Board Connector, KK 5045 Series, Through Hole, Header, 4, 2.5 mm, Tin Plated Contacts RoHS Compliant: Yes | 22041041 | 1 | Buy Now |
| MULTICOMP PRO SMD Chip Resistor, 7.5 kohm, ± 0.1%, 100 mW, 0805 [2012 Metric], Thin Film, Precision | 0805W8F7501T5E | 1 | Buy Now |
| SUSUMU SMD Chip Resistor, 200 ohm, ± 0.1%, 100 mW, 0805 [2012 Metric], Thin Film, Precision | 0805W8F2000T5E | 1 | Buy Now |
| TEXAS INSTRUMENTS SWITCH, ANALOG 1-OHM SPDT, 5A3159 | TS5A3159DBVR | 1 | Buy Now |
| NEXPERIA ANALOGUE MUX/DEMUX, 16:1, 180R, TSSOP-24 | 74HC4067PW,118 | 1 | Buy Now |
| MULTICOMP PRO SMD Multilayer Ceramic Capacitor, 6800 pF, 50 V, 0805 [2012 Metric], ± 10%, X7R, MC Series | 0805B682K500NT | 2 | Buy Now |
| MULTICOMP PRO SMD Multilayer Ceramic Capacitor, MC Series, 0.033 F, 10%, X7R, 50 V, 0805 [2012 Metric] RoHS Compliant: Yes | 0805B333K500NT | 2 | Buy Now |
| PANASONIC CAP, 22UF, 25VDC, ALU ELEC, HYBRID, SMD ROHS COMPLIANT: YES | RVT1E220M0505 | 1 | Buy Now |
| VISHAY RESISTOR, RCS0805 100 390R ET1 E3 ROHS COMPLIANT: YES | RCS0805390RFKEA | 2 | Buy Now |
| MULTICOMP SMD Current Sense Resistors, MC Series, 24 kohm, 100 mW, - 1%, 150 V, 0805 [2012 Metric] RoHS Compliant: Yes | 0805W8F2402T5E | 1 | Buy Now |
| MULTICOMP SMD Current Sense Resistors, MC Series, 33 kohm, 100 mW, - 1%, 150 V, 0805 [2012 Metric] RoHS Compliant: Yes | 0805W8F3302T5E | 1 | Buy Now |
| MULTICOMP PRO SMD Current Sense Resistors, MC Series, 3.3 kohm, 100 mW, - 5%, 150 V, 0805 [2012 Metric] RoHS Compliant: Yes | 0805W8F3301T5E | 2 | Buy Now |
| MULTICOMP PRO SMD Current Sense Resistors, MC Series, 560 ohm, 100 mW, - 5%, 150 V, 0805 [2012 Metric] RoHS Compliant: Yes | 0805W8F5600T5E | 1 | Buy Now |
| BOURNS TRIMMER, 25 TURN 100K | 3296W-1-104 | 1 | Buy Now |
| BOURNS TRIMMER, 25 TURN 1M | 3296W-1-105 | 1 | Buy Now |
| BOURNS TRIMMER, 25 TURN 50K | 3296W-1-503 | 1 | Buy Now |
| STMICROELECTRONICS Operational Amplifier, Dual, 4 MHz, 2, 16 V/ s, 6V to 36V, SOIC, 8 RoHS Compliant: Yes | TL082CDR | 1 | Buy Now |
| VISHAY Zener Single Diode, 3 V, 500 mW, SOD-123, 2 Pins, 150 °C, Surface Mount | MMSZ4683 | 1 | Buy Now |
| VISHAY CAP, 0.068µF, 50V, 10%, X7R, 0805 | 0805B683K500NT | 4 | Buy Now |
| BOURNS Trimpot, Multi Turn, Cermet, Top Adjust, 200 kohm, Through Hole, 25 Turns | 3296W-1-204 | 1 | Buy Now |
| YAGEO SMD Multilayer Ceramic Capacitor, 0.1 µF, 50 V, 0805 [2012 Metric], ± 10%, X7R, CC Series | CC0805KRX7R9BB104 | 14 | Buy Now |
| C46,C49,C50,C51,C52,C53" | undefined | undefined | Buy Now |
| PHOENIX CONTACT Wire-To-Board Terminal Block, 5.08 mm, 2 Positions, 26 AWG, 14 AWG, 2.5 mm², Screw | 1715721 | 2 | Buy Now |
| PHOENIX CONTACT Wire-To-Board Terminal Block, 5.08 mm, 3 Positions, 26 AWG, 14 AWG, 2.5 mm², Screw | 1715734 | 1 | Buy Now |
| SAMSUNG ELECTRO-MECHANICS SMD Multilayer Ceramic Capacitor, 4.7 µF, 25 V, 0805 [2012 Metric], ± 10%, X5R, CL Series | CL21A475KAQNNNE | 10 | Buy Now |
| SAMSUNG ELECTRO-MECHANICS SMD Multilayer Ceramic Capacitor, 10000 pF, 50 V, 0805 [2012 Metric], ± 10%, X7R, CL Series | CL21B103KBANNNC | 2 | Buy Now |
| SAMSUNG ELECTRO-MECHANICS SMD Multilayer Ceramic Capacitor, 1 µF, 50 V, 0805 [2012 Metric], ± 10%, X7R, CL Series | CL21B105KBFNNNE | 4 | Buy Now |
| SAMSUNG ELECTRO-MECHANICS SMD Multilayer Ceramic Capacitor, 0.22 µF, 50 V, 0805 [2012 Metric], ± 10%, X7R, CL Series | CL21B224KBFNNNE | 1 | Buy Now |
| SAMSUNG ELECTRO-MECHANICS SMD Multilayer Ceramic Capacitor, 0.47 µF, 50 V, 0805 [2012 Metric], ± 10%, X7R, CL Series | CL21B474KBFNNNE | 4 | Buy Now |
| KEMET Multilayer Ceramic Capacitor, AEC-Q200 MLCC Series, 2200 pF, - 5%, C0G / NP0, 50 V RoHS Compliant: Yes | CL21C222JBFNNNE | 2 | Buy Now |
| MULTICOMP PRO SMD Chip Resistor, 10 kohm, ± 5%, 125 mW, 0805 [2012 Metric], Thick Film, Sulfur Resistant | 0805W8F1002T5E | 4 | Buy Now |
| MULTICOMP PRO Surface Mount Chip Resistor, Ceramic, MCMR Series, 240 ohm, 125 mW, 1%, 150 V, 0805 [2012 Metric] RoHS Compliant: Yes | 0805W8F2400T5E | 1 | Buy Now |
| MULTICOMP PRO Surface Mount Thick Film Resistor, MCMR Series, 2.4 kohm, 125 mW, - 1%, 150 V RoHS Compliant: Yes | 0805W8F2401T5E | 1 | Buy Now |
| MULTICOMP PRO Surface Mount Chip Resistor, Ceramic, MCMR Series, 3 kohm, 125 mW, 1%, 150 V, 0805 [2012 Metric] RoHS Compliant: Yes | 0805W8F3001T5E | 1 | Buy Now |
| MULTICOMP PRO Surface Mount Chip Resistor, Ceramic, MCMR Series, 30 kohm, 125 mW, 1%, 150 V, 0805 [2012 Metric] RoHS Compliant: Yes | 0805W8F3002T5E | 1 | Buy Now |
| MULTICOMP PRO Surface Mount Thick Film Resistor, MCMR Series, 4.7 kohm, 125 mW, - 1%, 150 V RoHS Compliant: Yes | 0805W8F4701T5E | 10 | Buy Now |
| MULTICOMP PRO Surface Mount Chip Resistor, Ceramic, MCMR Series, 510 ohm, 125 mW, 1%, 150 V, 0805 [2012 Metric] RoHS Compliant: Yes | 0805W8F5100T5E | 2 | Buy Now |
| MULTICOMP PRO Surface Mount Chip Resistor, Ceramic, MCMR Series, 68 kohm, 125 mW, 1%, 150 V, 0805 [2012 Metric] RoHS Compliant: Yes | 0805W8F6802T5E | 2 | Buy Now |
| MULTICOMP PRO Surface Mount Chip Resistor, Ceramic, MCMR Series, 47 kohm, 125 mW, 5%, 150 V, 0805 [2012 Metric] RoHS Compliant: Yes | 0805W8F4702T5E | 4 | Buy Now |
| MULTICOMP PRO Surface Mount Chip Resistor, Ceramic, MCMR Series, 75 kohm, 125 mW, 1%, 150 V, 0805 [2012 Metric] RoHS Compliant: Yes | 0805W8F7502T5E | 1 | Buy Now |
| MULTICOMP PRO Surface Mount Thick Film Resistor, MCSR 08 Series, 220 ohm, 125 mW, - 1%, 150 V RoHS Compliant: Yes | 0805W8F2200T5E | 1 | Buy Now |
| MULTICOMP PRO Surface Mount Thick Film Resistor, MCSR 08 Series, 27 kohm, 125 mW, - 1%, 150 V RoHS Compliant: Yes | 0805W8F2702T5E | 2 | Buy Now |
| MULTICOMP PRO Surface Mount Thick Film Resistor, MCSR 08 Series, 470 ohm, 125 mW, - 1%, 150 V RoHS Compliant: Yes | 0805W8F4700T5E | 3 | Buy Now |
| MULTICOMP PRO Surface Mount Thick Film Resistor, MCSR 08 Series, 5.1 kohm, 125 mW, - 1%, 150 V RoHS Compliant: Yes | 0805W8F5101T5E | 2 | Buy Now |
| MULTICOMP PRO Surface Mount Thick Film Resistor, MCSR 08 Series, 56 kohm, 125 mW, - 1%, 150 V RoHS Compliant: Yes | 0805W8F5602T5E | 2 | Buy Now |
| MULTICOMP PRO Surface Mount Thick Film Resistor, MCSR 08 Series, 6.2 kohm, 125 mW, - 1%, 150 V RoHS Compliant: Yes | 0805W8F6201T5E | 1 | Buy Now |
| MULTICOMP PRO Surface Mount Thick Film Resistor, MCSR 08 Series, 62 kohm, 125 mW, - 1%, 150 V RoHS Compliant: Yes | 0805W8F6202T5E | 1 | Buy Now |
| MULTICOMP PRO Surface Mount Thick Film Resistor, MCSR 08 Series, 6.8 kohm, 125 mW, - 1%, 150 V RoHS Compliant: Yes | 0805W8F6801T5E | 2 | Buy Now |
| STMICROELECTRONICS Operational Amplifier, QUAD, 4 MHz, 4, 16 V/ s, 6V to 36V, SOIC, 14 RoHS Compliant: Yes | TL084CDR | 3 | Buy Now |
| MOLEX Pin Header, Wire-to-Board, 2.5 mm, 1 Rows, 7 Contacts, Through Hole Straight, KK 5045 Series | 22041071 | 2 | Buy Now |
Additional Parts:
| ESP32_DevKit_V1_DOIT |
| RegulatorLM1084S-5.0/TR |
| Fuse 5TR4A 250V |
| Lego bricks misc. See Lego BOM list |
| Or, order it here! |
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