2 layers30.4 × 12.7 mm
2 layers40.7 × 66.4 mm
Timer Dongle
Annicat3/Timer-DongleA small USB timer Dongle with 6 LEDs, a buzzer and a cute cat-shaped PCB.
- Size
- 40.7 × 66.4 mm
- Copper layers
- 2
- Thickness
- 1 mm
- Parts
- 21
- Nets
- 23
- Pads
- 58
- Tracks, vias
- 164, 3
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 26 Aug 2026
- Updated
- 13 Sep 2026
Overview
Timer Dongle is an open-source printed circuit board by Annicat3, from the Annicat3/Timer-Dongle repository on GitHub, published under the MIT licence. It is a 2-layer board of 40.7 × 66.4 mm with 21 parts on 23 nets, routed with 164 tracks and 3 vias.
It is built around the CH552G. Its parts include 6 resistors, 6 diodes, 2 capacitors, 1 IC and 1 connector. It belongs with the 8051 (CH55x, STC, AT89) boards of this library.
Main components
1README
README.mdTimer-Dongle
What is it?
This project is a small USB timer based on the CH552G microcontroller. It has 6 LEDs, a piezo buzzer and 2 buttons.
The time can be selected in 10-minute steps, from 10 to 60 minutes. The LEDs show the selected time ans later show the progress of the timer.
When the Timer finishes, the LEDs blink and the buzzer makes a sound.
Why did I make it?
I wanted to make something useful that I could actually use while working or studying. I also thought it would be fun to turn a simple electronic project into something with personality.
Instead of using a normal rectangular PCB, I designed mine in the shape of a cat. I also added a small cat face and other details to the silkscreen.
How does it work?
- Plug the timer into a USB port.
- Press the time button to choose a time from 10 to 60 minutes.
- Press the start button to start the timer.
- The six LEDs slowly turn off as the timer runs.
- When the timer reaches zero, the LEDs blink and the buzzer sounds.
- Press the time button to stop the alarm and choose a new time.
PCB
I designed the schematic and PCB in KiCad.
Schematic
3D View
Firmware
The Firmware is written for the CH552G using CH55xduino.
CAD
I also experimented with designing a simple case for the PCB in Onshape.
Onshape link
Bill of Materials (BOM)
| Item | Qty | Cost | Link |
|---|---|---|---|
| PCB | 5 | $20.70 | Gerber files |
| 3D printed case | 1 | Stl File | |
| WCH CH552G Microcontroller | 1 | $0.75 | LCSC C111292 |
| Murata GRM188R72A104KA35D, 100nF, 0603 | 2 | $0.18 | LCSC C77058 |
| YAGEO RT0603BRD07470RL, 470Ω, 0603 | 6 | $0.55 | LCSC C705779 |
| Panasonic ERA3AEB103V, 10kΩ, 0603 | 1 | $0.53 | LCSC C190610 |
| XUNPU TS-1088-AC02016 tactile switch | 3 | $0.69 | LCSC C720475 |
| Murata PKMCS0909E4000-R1 Piezo Buzzer | 1 | $1.02 | LCSC C910763 |
| 0805 SMD LEDs | 6 | $2.43 | LCSC C5879058 |
| JLCPCB Shipping | $7.11 | ||
| JLCPCB Taxes & Customs | $11.63 | ||
| JLCPCB Payment Fee | $0.50 | ||
| LCSC Shipping | $9.82 | ||
| LCSC Handling Fee | $3.00 | ||
| LCSC Tariff / Import Taxes | $17.35 | ||
| Total | $76,26 |
Hack Club Dongle YSWS
This project was created as part of Hack Club's YSWS program, Dongle. It was my first time designing a PCB and I learned a lot about schematics, PCB design, routing, and choosing components along the way.
Parts
21| Qty | Value | Footprint | References |
|---|---|---|---|
| 6 | 470 | Resistor_SMD:R_0603_1608Metric | R2, R3, R4, R5, R6, R7 |
| 6 | LED | LED_SMD:LED_0805_2012Metric | D1, D2, D3, D4, D5, D6 |
| 3 | SW_Push | Button_Switch_SMD:SW_SPST_TS-1088-xR020 | SW_start1, SW_time1, SW1 |
| 2 | 100nF | Capacitor_SMD:C_0603_1608Metric | C1, C2 |
| 1 | 10k | Resistor_SMD:R_0603_1608Metric | R_SW1 |
| 1 | Buzzer | Buzzer_Beeper:Buzzer_Murata_PKMCS0909E | BZ1 |
| 1 | CH552G | Package_SO:JEITA_SOIC-16_3.9x9.9mm_P1.27mm | U1 |
| 1 | USB_A | CH552G:USB-A | J1 |
Questions
How big is the Timer Dongle PCB?
It measures 40.7 × 66.4 mm and has 2 copper layers, 1 mm thick.
What parts does the Timer Dongle use?
21 parts, built around the CH552G. 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 Timer Dongle KiCad files?
From the Annicat3/Timer-Dongle repository on GitHub, at the commit this page was made from: the board is PCB/Timer.Dongle.kicad_pcb and its schematic PCB/Timer.Dongle.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Timer Dongle 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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