Friday, November 19, 2010

Schematic- Arduino Spectrum Analyzer

Arduino Spectrum Analyzer with Video Out - Schematic

(1)  2n3904 NPN Transistor [Q1]
(3)  1k Ohm Resistor [R2,R4,R5]
(1)  330 Ohm Resistor [R6]
(1)  10k Ohm Resistor [R1]
(1) 100k Ohm Resistor [R3]
(1) Electrolytic Capacitor, 3.3MF [C1]
(1) Electret Microphone [MIC1]

If gain is insufficient, replace Q1 (2n3904 transistor) with higher gain transistor or darlington pair.

Video out is NTSC/PAL Composite, if necessary a coupling capacitor and diode can be added.

The code for this version is on the previous blog entry, a revised version of both the code and the circuit will be posted within the next several days, as the TVout library is being re-released with significant changes which make compatibility with this setup a problem.  I'm waiting on releasing the new code and circuit until the library author's release, to avoid confusing folks.


  1. Can we see the code? Thank you

  2. Yep.. it's in the previous post for my code, and links to the libraries which made it possible.

  3. Note: TV library update is coming this week, and I'll be posting a new version of the code and circuit reflecting those changes after the library's author releases it. For the purposes of this project, the largest impact will be the re-assignment of the pins the video is generated on.. so the resistors (c5,c6) will be going to different pins, as defined in the new version of the library. This version is built with the 5.91 version of the library.

  4. Hi, is there a new version of the code and circuit for TVout Beta1 for version 1.0? I notice they changed the resistor on the video out from 330 to 470.

  5. I've redone the circuit and code reflecting the new library, I've also done an alternate circuit for the amplifier using an LM386 audio amplifier chip as a lower-noise alternative to the single-transistor amp. I'll be posting the writeup shortly.

  6. Is that 3.3 MegaFarad or MicroFarad?