MOST25-to-AUDIO
About the MOST25-to-AUDIO PCB
MOST25-to-AUDIO is an open source ESP32 PCB design by Oleg-mk, published on GitHub under the CERN-OHL-S-2.0 license. It is a 4-layer board measuring 98 × 60 mm, with 174 components from 69 distinct parts.
Its main chip is the ESP32-DevKitC-VIE, from the ESP32 family. Other key parts include the 74LVC1G34, 74LVC1G157, 74LVC1G125, 74LVC1G123 and TPS7B8133DRV. By type, the board carries 80 capacitors, 52 resistors, 18 ICs, 9 connectors, 6 diodes and 5 inductors.
It belongs with the audio and iot & wireless designs in this gallery, and the repository also holds 1 earlier revision of it.
From the project
Passive MOST25 listener: Tang Nano 20K FPGA, ESP32 host, stereo I2S out with the head unit's volume, balance and tone
A passive listener for the MOST25 optical ring in a car. It sits in the fibre as an invisible repeater - physically present, never a node: no address, never a word on the control channel - and turns what the ring carries into audio and data the owner can use:
- J3: what the factory amplifier would play, as stereo I2S and, the same stream, as S/PDIF on TOSLINK and coax: the main source with the head unit's volume, mute, balance, bass, treble and loudness applied, and up to three more of the amplifier's sinks - navigation and phone, the parking sensors, the chimes, where the car sends them as…
Main components on the MOST25-to-AUDIO
MOST25-to-AUDIO bill of materials (BOM)
174 components, 69 distinct parts — part numbers from the project's BOM.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | 74LVC1G34 | SOT-353_SC-70-5 | U1 |
| 1 | 74LVC1G157 | SOT-363_SC-70-6 | U2 |
| 1 | 74LVC1G125 | SOT-353_SC-70-5 | U3 |
| 2 | 74LVC1G123 | VSSOP-8_2.3x2mm_P0.5mm | U4, U11 |
| 1 | TPS7B8133DRV | WSON-6-1EP_2x2mm_P0.65mm_EP1x1.6mm | U5 |
| 1 | LMR38020F | Texas_HSOP-8-1EP_3.9x4.9mm_P1.27mm_ThermalVias | U6 |
| 1 | SI514 Si514 | Si514_3.2x5_2.5x3.2 | U7 |
| 3 | LP5907MFX-3.3 | SOT-23-5 | U8, U14, U16 |
| 1 | 74LVC1G79 | SOT-353_SC-70-5 | U9 |
| 1 | TPS2553DBVR | SOT-23-6 | U10 |
| 1 | DIR9001 | TSSOP-28_4.4x9.7mm_P0.65mm | U12 |
| 1 | SRC4192 | SSOP-28_5.3x10.2mm_P0.65mm | U13 |
| 1 | PCM5102A | TSSOP-20_4.4x6.5mm_P0.65mm | U15 |
| 1 | OPA1678 | SOIC-8_3.9x4.9mm_P1.27mm | U17 |
| 1 | TPS60403 | SOT-23-5 | U18 |
| 1 | Tang Nano 20K | Sipeed_TangNano20K | M1 |
| 1 | ESP32-DevKitC-VIE | Espressif_ESP32-DevKitC_V4 | M2 |
| 1 | 24.576MHZ 24.576MHz | Oscillator_SMD_Abracon_ASE-4Pin_3.2x2.5mm | X1 |
| 1 | 1-1394640-1 | TE_MOST_Pigtail_FOT_2+0 | J1 |
| 1 | ANALYSER | PinHeader_1x08_P2.54mm_Vertical | J2 |
Show 49 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | I2S | PinHeader_1x06_P2.54mm_Vertical | J3 |
| 1 | VBAT_IN | Molex_Micro-Fit_3.0_43650-0200_1x02_P3.00mm_Horizontal | J4 |
| 1 | FCR684208R | Cliff_TOSLINK_ORJ8_OTJ8 | J5 |
| 1 | FCR684208T | Cliff_TOSLINK_ORJ8_OTJ8 | J6 |
| 1 | RCA 75R | BKL_0101153_RCA_RA | J7 |
| 1 | LINE L | BKL_0101153_RCA_RA | J8 |
| 1 | LINE R | BKL_0101153_RCA_RA | J9 |
| 1 | C2925010 2A T | Fuse_1206_3216Metric | F1 |
| 2 | SS34 | D_SMA | D1, D3 |
| 1 | SMBJ36A | D_SMB | D2 |
| 3 | PESD5V0S1BL | D_SOD-882 | D4, D5, D6 |
| 3 | 600R | L_0603_1608Metric | FB1, FB2, FB3 |
| 1 | 15U 15u | L_Bourns_SRN6045TA | L1 |
| 1 | 22U 22u | L_Bourns-SRN8040_8x8.15mm | L2 |
| 1 | C576517 10u 100V | C_1210_3225Metric | C1 |
| 6 | C15725 100n 100V | C_0603_1608Metric | C2, C43, C46, C47, C82, C83 |
| 4 | 2U2 2u2 | C_0603_1608Metric | C3, C53, C57, C58 |
| 1 | C385986 4u7 100V | C_1210_3225Metric | C4 |
| 31 | 100N 100n | C_0603_1608Metric | C6, C8, C10, C11, C12, C13, C16, C17 +23 |
| 1 | C77101 47u 10V | C_1210_3225Metric | C7 |
| 10 | 1u | C_0603_1608Metric | C9, C14, C15, C40, C48, C49, C50, C51 +2 |
| 8 | 10U 10u | C_0805_2012Metric | C18, C20, C33, C35, C37, C60, C84, C85 |
| 1 | C15850 10u 16V | C_0805_2012Metric | C23 |
| 1 | C15850 10u 6V3 | C_0805_2012Metric | C24 |
| 1 | 1n | C_0603_1608Metric | C25 |
| 1 | 68N 68n | C_0603_1608Metric | C27 |
| 1 | 4N7 4n7 | C_0603_1608Metric | C28 |
| 2 | C53330124 100u 63V | CP_Elec_10x10.5 | C44, C45 |
| 2 | 4U7 4u7 | C_0805_2012Metric | C55, C75 |
| 2 | 2N2 2n2 | C_0603_1608Metric | C61, C62 |
| 3 | C359220 100u 16V | CP_Elec_6.3x7.7 | C63, C78, C81 |
| 2 | 820P 820p | C_0603_1608Metric | C69, C70 |
| 2 | 390P 390p | C_0603_1608Metric | C71, C72 |
| 2 | 150 | R_0603_1608Metric | R1, R2 |
| 2 | 27K 27k | R_0603_1608Metric | R3, R42 |
| 3 | 100K 100k | R_0603_1608Metric | R4, R6, R7 |
| 1 | 23K2 23k2 | R_0603_1608Metric | R5 |
| 6 | 10K 10k | R_0603_1608Metric | R8, R9, R14, R17, R23, R30 |
| 2 | 22 | R_0603_1608Metric | R10, R15 |
| 2 | 2k | R_0603_1608Metric | R11, R12 |
| 20 | 33 | R_0603_1608Metric | R16, R18, R19, R20, R21, R28, R29, R34 +12 |
| 1 | C25962 24k9 1% | R_0603_1608Metric | R22 |
| 1 | 680 | R_0603_1608Metric | R24 |
| 3 | 100 | R_0603_1608Metric | R25, R45, R46 |
| 1 | 240 | R_0603_1608Metric | R26 |
| 1 | 110 | R_0603_1608Metric | R27 |
| 1 | C14891 64k9 1% | R_0603_1608Metric | R31 |
| 4 | 4K7 4k7 | R_0603_1608Metric | R32, R33, R43, R44 |
| 2 | 10 | R_0603_1608Metric | R47, R48 |
MOST25-to-AUDIO design files
The KiCad project lives in the Oleg-mk/MOST25-to-AUDIO repository on GitHub; these links point at the commit this page was built from.
MOST25-to-AUDIO: common questions
What microcontroller does the MOST25-to-AUDIO use?
The MOST25-to-AUDIO is built around the ESP32-DevKitC-VIE, from the ESP32 family.
How big is the MOST25-to-AUDIO PCB?
The MOST25-to-AUDIO measures 98 × 60 mm, has 4 copper layers and is 1.6 mm thick.
How many components are on the MOST25-to-AUDIO?
174 components, from 69 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.
Where can I download the MOST25-to-AUDIO design files?
From the Oleg-mk/MOST25-to-AUDIO repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.
Can I use the MOST25-to-AUDIO design in my own project?
Yes, under the terms of its CERN-OHL-S-2.0 license, which Oleg-mk chose for the repository.
Can I test firmware for the MOST25-to-AUDIO without the hardware?
Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug ESP32 firmware against it before you order a PCB.
Earlier revisions in the repo: most_listener
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