2 layers44.2 × 29.3 mm
2 layers50 × 50 mm
Soldering Sponge Automatic Water Dispenser
EECSB/Soldering-Sponge-Automatic-Water-DispenserATtiny45-based device that keeps a soldering sponge moist automatically (3D-printed case + KiCad PCB + firmware).
- Size
- 50 × 50 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 23
- Nets
- 16
- Pads
- 52
- Tracks, vias
- 103, 0
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 18 May 2026
- Updated
- 24 Jul 2026
Overview
Soldering Sponge Automatic Water Dispenser is an open-source printed circuit board by EECSB, from the EECSB/Soldering-Sponge-Automatic-Water-Dispenser repository on GitHub, published under the Unlicense licence. It is a 2-layer board of 50 × 50 mm with 23 parts on 16 nets, routed with 103 tracks and 0 vias.
It is built around the ATTINY45-20PU and IRLZ44N. Its parts include 6 diodes, 6 connectors, 4 capacitors, 4 resistors and 2 ICs. It belongs with the AVR (ATmega, ATtiny) boards of this library.
Main components
2README
README.mdSoldering Sponge Automatic Water Dispenser
About
This is an automatic soldering sponge water dispenser. I got tired of the soldering sponge drying out, so I built an automatic water dispenser to “water” it. The dispenser uses a sensor to measure the resistance of the sponge. If the sponge dries out too much, the resistance goes up, the microcontroller detects it and turns on the pump.
Here you can find all the files related to the Soldering Sponge Automatic Water Dispenser build:
- Case 3D Files
- Firmware for the Attiny45
- KiCad Files
For more information about the project, see my blog posts: Soldering Sponge Automatic Water Dispenser
Build
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Parts
23| Qty | Value | Footprint | References |
|---|---|---|---|
| 5 | 1N4001 | Diode_THT:D_DO-41_SOD81_P10.16mm_Horizontal | D1, D2, D3, D4, D5 |
| 2 | 12V AC | Connector_Wire:SolderWire-0.1sqmm_1x01_D0.4mm_OD1mm | J1, J2 |
| 2 | 470uF | Capacitor_THT:CP_Radial_D10.0mm_P5.00mm | C1, C2 |
| 1 | 0.1uF | Capacitor_THT:C_Disc_D3.0mm_W1.6mm_P2.50mm | C4 |
| 1 | 100 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R2 |
| 1 | 100K | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R4 |
| 1 | 10K | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R1 |
| 1 | 10uF | Capacitor_THT:CP_Radial_D5.0mm_P2.00mm | C3 |
| 1 | 1K | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R3 |
| 1 | ATtiny45-20P | Package_DIP:DIP-8_W7.62mm | U2 |
| 1 | IRLZ44N | Package_TO_SOT_THT:TO-220-3_Vertical | Q1 |
| 1 | LED Pump Indicator | LED_THT:LED_D3.0mm | D6 |
| 1 | LM7805_TO220 | Package_TO_SOT_THT:TO-220-3_Vertical | U1 |
| 1 | Manual Watering Push Button | CustomAudio:3.5mm Jack 2 | J5 |
| 1 | Motor + | Connector_Wire:SolderWire-0.1sqmm_1x01_D0.4mm_OD1mm | J3 |
| 1 | Motor - | Connector_Wire:SolderWire-0.1sqmm_1x01_D0.4mm_OD1mm | J4 |
| 1 | Sensor | CustomAudio:3.5mm Jack 2 | J6 |
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Questions
How big is the Soldering Sponge Automatic Water Dispenser PCB?
It measures 50 × 50 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Soldering Sponge Automatic Water Dispenser use?
23 parts, built around the ATTINY45-20PU and IRLZ44N. 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 Soldering Sponge Automatic Water Dispenser KiCad files?
From the EECSB/Soldering-Sponge-Automatic-Water-Dispenser repository on GitHub, at the commit this page was made from: the board is Soldering Sponge Automatic Water Dispenser PCB/Soldering Sponge Automatic Water Dispenser.kicad_pcb and its schematic Soldering Sponge Automatic Water Dispenser PCB/Soldering Sponge Automatic Water Dispenser.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Soldering Sponge Automatic Water Dispenser design in my own project?
Its repository publishes it under the Unlicense licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).