2 layers78 × 54 mm
2 layers98 × 36.2 mm
Electronic limit sw
dilshan/electronic-limit-switch1Automatic fluid level control module
- Size
- 98 × 36.2 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 33
- Nets
- 20
- Pads
- 81
- Tracks, vias
- 210, 9
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 1 Jul 2025
- Updated
- 18 Jul 2025
Overview
Electronic limit sw is an open-source printed circuit board by dilshan, from the dilshan/electronic-limit-switch repository on GitHub, published under the MIT licence. It is a 2-layer board of 98 × 36.2 mm with 33 parts on 20 nets, routed with 210 tracks and 9 vias.
It is built around the HLK-2M05, ZMM5V6 and 10D561K, with the MMBT2222 and SMBJ6.0A among its other parts. Its parts include 7 diodes, 6 resistors, 5 capacitors, 4 connectors and 1 IC. It belongs with the robots and motor control boards and the PIC boards of this library.
Main components
5
HLK-2M05
SIP,30x16mm0.1W 16mm 19mm 2W 30mm 3kV 400mA 50mVp-p 5V 90VAC~245VAC AC-DC Short Circuit Protection、Over Current Protection SIP,30x16mm AC-DC Power Modules ROHSHI-LINKAC-DC Power Modules
ZMM5V6
LL-34-55℃~+175℃ 1 Independent 100nA 25Ω 450Ω 5.2V~6V 5.6V 500mW LL-34 Zener Diodes ROHSSTMicroelectronicsZener Diodes
10D561K
插件,P=7.5mm180pF@1kHz 2.5kA 350V 460V 504V~616V 70J 925V 插件,P=7.5mm Varistors ROHSSURGINGVaristors
MMBT2222
SOT-231 NPN 1uA 300mV 300mW 400 40V 600mA 6V NPN SOT-23 Bipolar (BJT) ROHSYONGYUTAIBipolar (BJT)
SMBJ6.0A
DO-214AA(SMB)-55℃~+150℃ 10.3V 58.25A@10/1000us 600W@10/1000us 6V 7.37V 800uA IEC 61000-4-2 TVS Unidirectional DO-214AA(SMB) ESD and Surge Protection (TVS/ESD) ROHShongjiachengESD And Surge Protection (TVS/ESD)
README
readme.mdElectronic Limit Switch
This is an open-source fluid level control module designed for reliable and automated liquid management in tanks.
Overview
This module can utilize two float-type limit switches or electronic sensor switches to detect fluid levels and control a relay accordingly. A microcontroller implements hysteresis logic to avoid unnecessary relay toggling caused by minor fluid level fluctuations, which enhances the system's reliability and lifespan.
How it works
-
The module monitors two limit switches:
- Upper limit switch (J1): Closes when the fluid level falls below the upper threshold.
- Lower limit switch (J2): Closes when the fluid level rises above the lower threshold.
-
Based on these inputs, the onboard microcontroller:
- Activates or deactivates the relay.
- Applies hysteresis logic to prevent rapid toggling.
-
The J4 terminal block provides:
- AC mains input (up to 240V).
- Relay output for controlling pumps or other devices.
License
This is a certified open-source hardware project. All design files, documentation, and firmware source code are available for download at the project source repository. The content of this project is distributed under the following licenses:
- Hardware license: CERN-OHL-W
- Software license: MIT License
- Documentation license: CC BY 4.0
Parts
33| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | M3 | MountingHole:MountingHole_3.5mm | H1, H2, H3, H4 |
| 4 | ZMM5V6 | Diode_SMD:D_MiniMELF_Handsoldering | D1, D2, D3, D4 |
| 3 | 1K | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R1, R2, R5 |
| 2 | 10K | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R4, R6 |
| 2 | 3.5mm - 2-pin screw terminal | Connector_Phoenix_MC:PhoenixContact_MCV_1,5_2-G-3.5_1x02_P3.50mm_Vertical | J1, J2 |
| 1 | 0.1MFD | Capacitor_THT:C_Rect_L11.0mm_W4.3mm_P10.00mm_MKT | C1 |
| 1 | 0.1MFD | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C3 |
| 1 | 0.22MFD | Capacitor_THT:C_Rect_L11.0mm_W5.1mm_P10.00mm_MKT | C2 |
| 1 | 0.5A | Fuse:Fuse_Littelfuse_372_D8.50mm | F1 |
| 1 | 10D561 | Varistor:RV_Disc_D12mm_W4.2mm_P7.5mm | TH1 |
| 1 | 10MFD | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C4 |
| 1 | 10mH | elect-footprints:CM-Choke-15.5mmx10.9mm | FL1 |
| 1 | 120R / 2W | Resistor_THT:R_Axial_DIN0516_L15.5mm_D5.0mm_P20.32mm_Horizontal | R3 |
| 1 | 330MFD | Capacitor_SMD:CP_Elec_6.3x7.7 | C5 |
| 1 | 7.62mm - 4-pin screw terminal | elect-footprints:Screw-Terminal-4Way-7.62mm | J4 |
| 1 | G2RL-2-DC5 | Relay_THT:Relay_DPDT_Omron_G2RL | RL1 |
| 1 | HLK-2M05 | elect-footprints:PSU-Module-10.5mmx16.5mm | PS1 |
| 1 | M1 | Diode_SMD:D_SMA_Handsoldering | D5 |
| 1 | MMBT2222 | Package_TO_SOT_SMD:SOT-23-3 | Q1 |
| 1 | PIC10F200-IOT | Package_TO_SOT_SMD:SOT-23-6 | U1 |
| 1 | RED 0805 | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D7 |
| 1 | SMBJ6.0A | Diode_SMD:D_SMB_Handsoldering | D6 |
| 1 | SMD - 2.54mm 4-pin pad terminal | elect-footprints:pogo-2.54mmx4 | J3 |
Questions
How big is the Electronic limit sw PCB?
It measures 98 × 36.2 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Electronic limit sw use?
33 parts, built around the HLK-2M05, ZMM5V6, 10D561K and MMBT2222. 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 Electronic limit sw KiCad files?
From the dilshan/electronic-limit-switch repository on GitHub, at the commit this page was made from: the board is design/electronic-limit-sw.kicad_pcb and its schematic design/electronic-limit-sw.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Electronic limit sw design in my own project?
Its repository publishes it under the MIT 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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