2 layers89 × 99 mm
2 layers22 × 53.5 mm
Isolated RS485 Bridge
Anderman/tombaskAll message send Slave can send after a poll frame. Slave is ready sending when the last padding byte is 0x55 To write byte 0x08 must be 0x02
- Size
- 22 × 53.5 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 22
- Nets
- 56
- Pads
- 148
- Tracks, vias
- 114, 21
- Pours
- 3
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 7 Dec 2025
- Updated
- 6 Jun 2026
Overview
Isolated RS485 Bridge is an open-source printed circuit board by Anderman, from the Anderman/tombask repository on GitHub. It is a 2-layer board of 22 × 53.5 mm with 22 parts on 56 nets, routed with 114 tracks and 21 vias.
It is built around the ESP32-S3-MINI-1-N8, THVD2450DRB and MEE1S0303SC, with the AP63203WU, Π122U31 and SS14 among its other parts. Its parts include 7 capacitors, 5 ICs, 4 diodes, 2 resistors and 1 connector. It belongs with the interfaces and adapters boards and the ESP32 boards of this library.
Main components
8
ESP32-S3-MINI-1-N8
SMD-104.5dBm -40℃~+85℃ 2.4GHz 20.5dBm 330mA 3V~3.6V 97mA Bluetooth5.0 ESP32-S3FN8 Chip On-board PCB Antenna UART、SPI、I2C、I2S、USB SMD WiFi Modules ROHSEspressif SystemsWiFi Modules
THVD2450DRB
SON-8-EP(3x3)-40℃~+125℃ 1 1 256 3V~5.5V 5.6mA 50Mbps Half-Duplex Transceiver ±16kV SON-8-EP(3x3) RS-485 / RS-422 ICs ROHSTexas InstrumentsRS-485 / RS-422 ICs
MEE1S0303SC
SIP-4SIP-4 Isolated Power Modules ROHSYLPTECIsolated Power Modules
AP63203WU
TSOT-23-6-40℃~+85℃@(TA) 1 1.1MHz 22uA 2A 3.3V 3.8V~32V Buck Built-in Fixed Overcurrent Protection、Light load efficient mode、Cycle-by-cycle current limiting、Hiccup current limiting、EMI optimization (spread spectrum) Step-down type Yes TSOT-23-6 DC-DC Converters ROHSDiodes IncorporatedDC-DC Converters
Π122U31
SOIC-8-40℃~+125℃ 1 1 150Kbps 150kV/us 3000 3V~5.5V 3V~5.5V 4.5us Fail-safe output High Level SOIC-8 Digital Isolators ROHS2Pai SemiDigital Isolators
SS14
SMA(DO-214AC)-55℃~+150℃ 1A 25A 300uA@40V 40V 550mV@1A Independent SMA(DO-214AC) Schottky Diodes ROHSMDDSchottky Diodes
SMF24A
SOD-123FL-65℃~+150℃ 1 1uA 200W 24V 26.7V、29.5V 38.9V 5.1A TVS Unidirectional SOD-123FL ESD and Surge Protection (TVS/ESD) ROHSHXY MOSFETESD And Surge Protection (TVS/ESD)
WS2812B-2020
SMD,2.2x2mm0.6mA 0.84mm 120us 160mcd 200mcd 2kHz 2mm 2mm 300ns 470.4nm 515.6nm 520mcd 5V 622.5nm 800Kbit/s Built-in power-on reset circuit、Built-in power-on reset circuit、Integrated intelligent reverse connection protection function Top-mount SMD,2.2x2mm RGB LEDs(Built-in IC) ROHSWorldsemiRGB LEDs(Built-In IC)
README
readme.mdTosot (Gree) Hombask 200Liter
The signal is custom rs485
All message send
12-07 12:47:05 frame=7e 7e 00 f0 00 04 90 31 01 64 47 00 (poll slave 0x00)
12-07 12:47:06 frame=7e 7e 01 f0 00 04 90 31 01 74 87 00 (poll slave 0x01)
12-07 12:47:06 frame=7e 7e f0 01 02 2d 90 31 01 15 21 9a 40 4a 02 c0 02 05 01 c7 01 0c 02 0e 02 c4 00 24 01 17 b4 00 00 00 00 55 8e 5d a7 15 b0 8e 00 aa ff ff ff ff ff 73 4a 57 55 (response slave 0x01)
12-07 12:47:06 frame=7e 7e 02 f0 00 04 90 31 01 47 87 00 (poll slave 0x02)
12-07 12:47:06 frame=7e 7e f0 f0 04 2d 90 31 01 15 21 9a 40 4a 02 c0 02 05 01 c7 01 0c 02 0e 02 c4 00 24 01 17 b4 00 00 00 00 55 8e 5d a7 15 b0 8e 00 aa ff ff ff ff ff 73 73 f6 00 (broadcast master)
12-07 12:47:06 frame=7e 7e f0 f0 06 1c 90 31 01 15 2c c0 01 00 00 10 ff ff 00 00 af b4 04 4b 73 5f 5a 3a 4b 00 00 00 00 99 1f 00 (broadcast master)
12-07 12:47:07 frame=7e 7e f0 f0 02 3c 90 31 01 77 98 00 7d 00 00 00 00 76 00 74 75 00 00 10 01 01 90 00 00 00 00 f8 00 00 00 00 00 00 00 11 8c 0f 9f c6 1d 98 15 00 00 00 00 70 9a 00 00 00 00 02 00 00 00 00 02 00 00 5a f0 00 (broadcast master)
12-07 12:47:07 frame=7e 7e f0 f0 03 25 90 31 06 00 00 00 14 14 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02 00 00 00 00 00 00 00 00 00 00 00 09 98 44 00 (broadcast master)
12-07 12:47:07 frame=7e 7e f0 f0 08 40 90 31 01 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ae 60 00 (broadcast master)Slave can send after a poll frame. Slave is ready sending when the last padding byte is 0x55 To write byte 0x08 must be 0x02
Aansluiting Rs485 signal for wired controller on H1(pos) and H2(neg) of the XT3 connector
App
Control page
temp history
mtqq settings
Logger (for debugging)
wifi settings
This is the wifimanger plugin
PCB
Parts
22| Qty | Value | Footprint | References |
|---|---|---|---|
| 3 | 100nF | Capacitor_SMD:C_0603_1608Metric | C2, C3, C6 |
| 3 | 22uF | Capacitor_SMD:C_0805_2012Metric | C4, C5, C8 |
| 2 | SS14 | 123:D_SOD-323HE | D3, D4 |
| 2 | π122U31 | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U3, U4 |
| 1 | 10K | Resistor_SMD:R_0603_1608Metric | R2 |
| 1 | 10R | Resistor_SMD:R_1206_3216Metric | R1 |
| 1 | 4.7uH | Inductor_SMD:L_Bourns-SRN4018 | L1 |
| 1 | 470uF | 123:CP_Elec_10x10 | C1 |
| 1 | AP63203WU | Package_TO_SOT_SMD:TSOT-23-6 | U2 |
| 1 | B | TerminalBlock_Phoenix:TerminalBlock_Phoenix_MKDS-1-2-3.81_1x02_P3.81mm_Horizontal | A1 |
| 1 | ESP32-S3-MINI-1 | PCM_Espressif:ESP32-S3-MINI-1 | U1 |
| 1 | MEE1S0303SC | Converter_DCDC:Converter_DCDC_Murata_MEE1SxxxxSC_THT | PS1 |
| 1 | SMF24A | 123:D_SOD-123FL | D1 |
| 1 | TC2030 | Connector:Tag-Connect_TC2030-IDC-NL_2x03_P1.27mm_Vertical | J1 |
| 1 | THVD2450DR | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U5 |
| 1 | WS2812B-2020 | 123:LED_WS2812B-2020_2x2.2mm | D2 |
Questions
How big is the Isolated RS485 Bridge PCB?
It measures 22 × 53.5 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Isolated RS485 Bridge use?
22 parts, built around the ESP32-S3-MINI-1-N8, THVD2450DRB, MEE1S0303SC and AP63203WU. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Isolated RS485 Bridge KiCad files?
From the Anderman/tombask repository on GitHub, at the commit this page was made from: the board is kiCad/Isolated_RS485_Bridge.kicad_pcb and its schematic kiCad/Isolated_RS485_Bridge.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Isolated RS485 Bridge design in my own project?
Its repository states no licence, so its author keeps all rights: ask Anderman before reusing the design.
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