4 layers48 × 87 mm
2 layers58 × 26.5 mm
Fireflies
cheyao/fireflies1Fireflies go blink ✨
- Size
- 58 × 26.5 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 52
- Nets
- 45
- Pads
- 172
- Tracks, vias
- 237, 53
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 12 May 2026
- Updated
- 11 Jun 2026
Overview
Fireflies is an open-source printed circuit board by cheyao, from the cheyao/fireflies repository on GitHub. It is a 2-layer board of 58 × 26.5 mm with 52 parts on 45 nets, routed with 237 tracks and 53 vias.
It is built around the MAC97A8, LTR-303ALS-01 and AO3416, with the 1N4148WS among its other parts. Its parts include 16 resistors, 7 capacitors, 6 diodes, 5 ICs and 3 transistors. It belongs with the RISC-V boards of this library.
Main components
4
MAC97A8
TO-92-40℃~+125℃ 1 TRIAC 1.2V 10mA 12A 1A 300mW 800V TO-92 Thyristors (SCR)/Modules ROHSKYThyristors (SCR)/Modules
LTR-303ALS-01
DFN-6(2x2)-30℃~+70℃ 0.7mm 16bit 2.4V~3.6V 2mm 2mm 64klx I2C Light Intensity Low power/sleep mode、Spectral correction/filtering、Adjustable gain control、Interrupt/event trigger、Built-in temperature compensation DFN-6(2x2) Ambient Light Sensors ROHSLite-OnAmbient Light Sensors
AO3416
SOT-23-55℃~+150℃ 1 N-channel 1.1V 1.4W 1.65nF 10nC@4.5V 20V 22mΩ@4.5V 6.5A 87pF SOT-23 MOSFETs ROHSAlpha & Omega SemiconductorMOSFETs
1N4148WS
SOD-3231.25V@150mA 100V 150mA 1uA@75V 200mW 2A 4ns Independent SOD-323 Switching Diodes ROHSJiangsu Changjing Electronics Technology (CJ)Switching Diodes
README
README.mdFireflies
Firefly PCBs powered by the CH32V003.
These boards periodically flashes a xenon flash based on a timer, which gets accelerated when it detects flashes from surrounding PCBs.
There are currently 2 flash-detection circuits undergoing testing:
-
A reverse-biased diode using the ch32v003's internal OPA & ADC for sampling
-
A I2C ambiant light sensor for more "advanced" applications
The flash trigger isolates the hi-voltage trigger and the low-voltage circuitarry with a triac circuit, and uses a mosfet to trigger the flash.
Features:
- Dual light-sensor: one via i2c, one via photodiode
- USB via ch32usb
- 7 seg for number display
- Flash activation circuit (high voltage)
- Programming ports
Usage
Check firmware folder
Here's an example output for detection light intensity with the photodiode:
It's reverse-biased btw
Schematic
Programming
Check diagram:
BOM
| Item | Price | Where |
|---|---|---|
| PCB | 4$ | elecrow |
| Stencil | 2$ | elecrow |
| Components (check hardware bom) | $30 | lcsc |
| Shipping | varies by region | none |
Parts
52| Qty | Value | Footprint | References |
|---|---|---|---|
| 5 | 470 | Resistor_SMD:R_0402_1005Metric | R1, R2, R3, R6, R7 |
| 4 | 1uF | Capacitor_SMD:C_0402_1005Metric | C3, C4, C5, C6 |
| 4 | 2.2k | Resistor_SMD:R_0402_1005Metric | R9, R10, R11, R12 |
| 4 | TestPoint | TestPoint:TestPoint_Pad_D1.0mm | TP1, TP2, TP3, TP4 |
| 3 | AO3416 | Package_TO_SOT_SMD:SOT-23 | Q1, Q2, Q3 |
| 2 | 1.5k | Resistor_SMD:R_0402_1005Metric | R15, R19 |
| 2 | 1N4004 | Diode_SMD:D_SOD-123F | D5, D6 |
| 2 | 4M7 | Resistor_SMD:R_0402_1005Metric | R16, R17 |
| 2 | 5.1k | Resistor_SMD:R_0402_1005Metric | R13, R14 |
| 2 | SW_Push | light:SW_Push_SPST_TSA016 | SW1, SW2 |
| 1 | 10uF | Capacitor_SMD:C_0402_1005Metric | C1 |
| 1 | 10uH | Inductor_SMD:L_0603_1608Metric | L1 |
| 1 | 18 | Resistor_SMD:R_0603_1608Metric | R18 |
| 1 | 1N4148WS | Diode_SMD:D_SOD-323 | D2 |
| 1 | 22n | Capacitor_SMD:C_0402_1005Metric | C7 |
| 1 | 22uF | Capacitor_SMD:C_0603_1608Metric | C2 |
| 1 | 5V6 | Diode_SMD:D_SOD-123 | D4 |
| 1 | Backup power | Jumper:SolderJumper-2_P1.3mm_Open_RoundedPad1.0x1.5mm | JP2 |
| 1 | CH32V003FxUx | Package_DFN_QFN:QFN-20-1EP_3x3mm_P0.4mm_EP1.65x1.65mm_ThermalVias | U2 |
| 1 | D_Photo | light:Photodiode_PD70-01C | D1 |
| 1 | Flash | Connector_Wire:SolderWire-0.5sqmm_1x02_P4.6mm_D0.9mm_OD2.1mm_Relief | J2 |
| 1 | Jump | Jumper:SolderJumper-2_P1.3mm_Bridged_RoundedPad1.0x1.5mm | JP4 |
| 1 | Jump | Jumper:SolderJumper-2_P1.3mm_Open_RoundedPad1.0x1.5mm | JP3 |
| 1 | LTR-303ALS-01 | OptoDevice:Lite-On_LTR-303ALS-01 | U3 |
| 1 | MAC97A8 | Package_TO_SOT_SMD:SOT-23-3 | D3 |
| 1 | Normal OP | Jumper:SolderJumper-2_P1.3mm_Bridged_RoundedPad1.0x1.5mm | JP1 |
| 1 | Solar_Lamp | Connector_Wire:SolderWire-0.5sqmm_1x02_P4.6mm_D0.9mm_OD2.1mm_Relief | BT1 |
| 1 | USB_C_Receptacle_USB2.0_14P | light:USB_C_Receptacle_SHOU_HAN_16PIN_2MD | J1 |
| 1 | XC6206PxxxMR | Package_TO_SOT_SMD:SOT-23-3 | U5 |
| 1 | XT1861 | Package_TO_SOT_SMD:SOT-23-3 | U4 |
| 1 | YD3622ARL | light:YD3622A | U1 |
The 51 most common of 52 parts.
Questions
How big is the Fireflies PCB?
It measures 58 × 26.5 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Fireflies use?
52 parts, built around the MAC97A8, LTR-303ALS-01, AO3416 and 1N4148WS. 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 Fireflies KiCad files?
From the cheyao/fireflies repository on GitHub, at the commit this page was made from: the board is pcb/fireflies.kicad_pcb and its schematic pcb/fireflies.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Fireflies design in my own project?
Its repository states no licence, so its author keeps all rights: ask cheyao before reusing the design.
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