2 layers91.3 × 57.5 mm
2 layers78.2 × 70.2 mm
HostBoard
comradef191/ThermEX17OSHW Thermistor expansion board for Klipper
- Size
- 78.2 × 70.2 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 61
- Nets
- 40
- Pads
- 177
- Tracks, vias
- 346, 77
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 9 Apr 2025
- Updated
- 24 Oct 2025
Overview
HostBoard is an open-source printed circuit board by comradef191, from the comradef191/ThermEX repository on GitHub, published under the CERN-OHL-S-2.0 licence. It is a 2-layer board of 78.2 × 70.2 mm with 61 parts on 40 nets, routed with 346 tracks and 77 vias.
It is built around the TPS7A2033PDBVR-TP. Its parts include 16 resistors, 16 connectors, 15 capacitors and 3 ICs.
Main components
1README
README.mdThermEX
A BlackPill powered expansion board for Klipper 3D printers, allowing the use of numerous additional Thermistors.
- Can be stacked ontop of or underneith Nyoomies using appropiate spacers
- OpenSource Hardware, licensed under the OHLv2-S
- 10 thermistors wired directly to the STM32
- 16 additional thermistors wired up via 4 ADS1115 ICs
- Powered directly from the USB port
- Uses an ultra-low-noise TPS7A2033 300mA 3.3v voltage regulator to power all expansion headers and the ADS1115s
- Features native support for the STM32F4x1 BlackPill, with the unused extra GPIO being broken out to a labelled expansion header alongside 3v3 & GND
- Breaks out the I2C2 & I2C3 busses to a pair of dedicated 4-pin JST-XH connectors
- Breaks out the SPI2 bus to a dedicated header, alongside PB12 to act as chip-select
NOTICE
if you are ordering a batch of PCBs, please for the love of god please use the pre-made gerber files in the Releases tab instead of downloading the repo, ignoring KiCADs warning you haven't got a font installed, and then exporting your own files which both have the I2C bus shorted out (rendering only 10 thermistor ports usable) due to the missing font breaking artwork on the copper layer plus has had markings crediting me destroyed.
Vendors
UK / EU
- None... yet!
Contact me on Discord if you want to add yourself to this list!
Bill of Materials
This BoM lists exclusively through-hole components, as SMD components will be assembled for you by JLCPCB
| Component | QTY | Cost | Comment | Sourcing URL |
|---|---|---|---|---|
| JST-XH 2-Pin | 26 | $0.39 | Thermistor Ports | https://www.lcsc.com/product-detail/Wire-To-Board-Connector_DEALON-XH-D-2A_C5160911.html |
| JST-XH 4-Pin | 2 | $0.52 | I2C Ports | https://www.lcsc.com/product-detail/Wire-To-Board-Connector_JST-B4B-XH-A-LF-SN_C144395.html |
| 2.54 Socket, 1x20 | 2 | $0.81 | STM32 Socket | https://www.lcsc.com/product-detail/Female-Headers_Shenzhen-Kinghelm-Elec-KH-2-54FH-1X20P-H8-5_C2905423.html |
| 2.54 Header, 2x5 | 3 | $0.40 | GPIO; Cut-Down for SPI | https://www.lcsc.com/product-detail/Pin-Headers_HanElectricity-2541WV-2x05P_C5383106.html |
| STM32F401 Blackpill | 1 | $3.25 | Main controller | https://www.aliexpress.com/item/1005006127461676.html |
Gallery
As of 09APR25 no ThermEX26 boards have been produced, thus only KiCad Renders are present currently
Parts
61| Qty | Value | Footprint | References |
|---|---|---|---|
| 12 | 100nF | Capacitor_SMD:C_0603_1608Metric | C2, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15 |
| 10 | 1x2-JSTXH | CustomFootprints:JST-XH_1x02-V ~ Custom | J7, J8, J9, J10, J11, J12, J13, J14, J15, J16 |
| 10 | 4.7kΩ | Resistor_SMD:R_0603_1608Metric | R7, R8, R9, R10, R11, R12, R13, R14, R15, R16 |
| 6 | DNP | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R1, R2, R3, R4, R5, R6 |
| 4 | M3 Mounting Hole | CustomFootprints:M3 Mounting Hole ~ Classic | H1, H2, H3, H4 |
| 3 | LOGO | LOGO | G***, G***, G*** |
| 3 | TestPoint | TestPoint:TestPoint_THTPad_D1.5mm_Drill0.7mm | TP1, TP2, TP3 |
| 2 | 1uF | Capacitor_SMD:C_0603_1608Metric | C1, C4 |
| 2 | 1x4-JSTXH | Connector_JST:JST_XH_B4B-XH-A_1x04_P2.50mm_Vertical | J5, J6 |
| 2 | 2.54_1x5-M | Connector_PinHeader_2.54mm:PinHeader_1x05_P2.54mm_Vertical | J1, J3 |
| 1 | 10uF | Capacitor_SMD:C_0603_1608Metric | C3 |
| 1 | 2.54_2x4-M | Connector_PinHeader_2.54mm:PinHeader_2x04_P2.54mm_Vertical | J4 |
| 1 | 2.54_2x5-M | Connector_PinHeader_2.54mm:PinHeader_2x05_P2.54mm_Vertical | J2 |
| 1 | TPS7A2033PDBVR | Package_TO_SOT_SMD:SOT-23-5 | U2 |
| 1 | ThermEX16 Slot | CustomFootprints:ThermEX16 | U3 |
| 1 | ~ | CustomFootprints:Socketed MCU - STM32 BlackPill | U1 |
The 60 most common of 61 parts.
Questions
How big is the HostBoard PCB?
It measures 78.2 × 70.2 mm and has 2 copper layers, 1.6 mm thick.
What parts does the HostBoard use?
61 parts, built around the TPS7A2033PDBVR-TP. 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 HostBoard KiCad files?
From the comradef191/ThermEX repository on GitHub, at the commit this page was made from: the board is LegacyVersions/ThermEX16-Carrier-V1/HostBoard.kicad_pcb and its schematic LegacyVersions/ThermEX10/ThermEX10.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the HostBoard design in my own project?
Its repository publishes it under the CERN-OHL-S-2.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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