2 layers29 × 18 mm
Helena ctrl
Reisi/Helena
Helena is an alternative driver for the Yinding or KD2 Headlight Cycling Lamp.
27 parts5BSD-2-Clause
2 layers22.1 × 18 mm
Helena base sd
Reisi/Helena5Helena is an alternative driver for the Yinding or KD2 Headlight Cycling Lamp.
- Size
- 22.1 × 18 mm
- Copper layers
- 2
- Thickness
- 0.8 mm
- Parts
- 59
- Nets
- 29
- Pads
- 136
- Tracks, vias
- 422, 40
- Pours
- 15
- Routed
- Yes
- KiCad
- KiCad 5 (file 20171130)
- Created
- 29 Dec 2016
- Updated
- 22 Jun 2025
Overview
Helena base sd is an open-source printed circuit board by Reisi, from the Reisi/Helena repository on GitHub, published under the BSD-2-Clause licence. It is a 2-layer board of 22.1 × 18 mm with 59 parts on 29 nets, routed with 422 tracks and 40 vias.
It is built around the MCP6482-E/MS, IRLML0030 and BC857C, with the SK24A, BAT54A and BSS138 among its other parts. Its parts include 14 capacitors, 14 resistors, 8 connectors, 7 diodes and 7 transistors. It belongs with the AVR (ATmega, ATtiny) boards of this library.
Main components
6
MCP6482-E/MS
MSOP-8-40℃~+125℃ 0.1pA 1.5mV 12mA 18nV/√Hz@10kHz 1pA 2 2.5uV/℃ 2.7V/us 240uA 4MHz 87dB Built-in compensation Rail-to-Rail Input, Rail-to-Rail Output MSOP-8 Operational Amplifier ROHSMicrochip TechnologyOperational Amplifier
IRLML0030
SOT-23-55℃~+150℃ 1 N-channel 2.3V 2.6nC 27mΩ@10V 30V 382pF 39pF 5.3A SOT-23 MOSFETs ROHSGuangdong HottechMOSFETsBC857C
SOT-23-65℃~+150℃ 1 PNP 100MHz 100mA 15nA 250mV 250mW 420 45V 5V PNP SOT-23 Bipolar (BJT) ROHSNexperiaBipolar (BJT)
SK24A
SMA(DO-214AC)-55℃~+150℃ 1 Independent 200uA@40V 2A 40V 50A 550mV@2A SMA(DO-214AC) Schottky Diodes ROHSSuzhou Good-Ark ElecSchottky DiodesBAT54A
SOT-231 Pair Common Anode 200mA 2uA@25V 30V 600mA 800mV@100mA SOT-23 Schottky Diodes ROHSNexperiaSchottky DiodesBSS138
SOT-23-55℃~+150℃ 1 N-channel 1.1Ω@10V、1.2Ω@4.5V 1.2V 1.7nC@10V 17.5pF 340mA 350mW 50V 6.5pF N-Channel SOT-23 MOSFETs ROHShongjiachengMOSFETs
README
README.mdHelena
Helena is an alternative driver for the Yinding or KD2 Headlight Cycling Lamp.
Main Features
- Two independant 3A Step-Down current converters.
- Bluetooth connectivity for remote control, configuration and lamp-to-lamp connection.
- Linear power reduction at low battery and high temperature.
- Standby current less than 150µA.
- Supports 1 (one LED), 2 (one or two LEDs) or 3 (up to three LEDs in series) cell Li-Ion battery.
- An integrated motion sensor to control the output current to reduce glare when looking down.
- A multi-functional com pin, can be used for wired communication or an external button.
License
This project is licensed under the BSD-2-clause License - see the license.txt file for details
Parts
59| Qty | Value | Footprint | References |
|---|---|---|---|
| 6 | 100n | Capacitor_SMD:C_0603_1608Metric | C2, C3, C4, C7, C11, C13 |
| 5 | 10k | Resistor_SMD:R_0603_1608Metric | R1, R6, R10, R13, R14 |
| 4 | CONN_01X01 | rt_pins:MILLMAX_5660 | P5, P6, P7, P8 |
| 4 | IRLML0030 | Package_TO_SOT_SMD:SOT-23 | Q3, Q4, Q6, Q7 |
| 3 | 10 | Resistor_SMD:R_0603_1608Metric | R2, R7, R9 |
| 3 | 3V3 | Package_TO_SOT_SMD:SOT-23 | D1, D4, D7 |
| 3 | CONN_01X01 | rt_pins:1,5x3mm_SMD | P1, P2, P3 |
| 2 | 10u/16 | Capacitor_SMD:C_0805_2012Metric | C5, C9 |
| 2 | 10u/16 | Capacitor_SMD:C_1206_3216Metric | C6, C8 |
| 2 | 1k5 | Resistor_SMD:R_0603_1608Metric | R5, R11 |
| 2 | 22n | Capacitor_SMD:C_0603_1608Metric | C1, C14 |
| 2 | 2u2/16 | Capacitor_SMD:C_0603_1608Metric | C10, C12 |
| 2 | 3u-18 | rt_chokes:Choke_SMD_Fastron_242418_FPS | L1, L2 |
| 2 | 680 | Resistor_SMD:R_0603_1608Metric | R4, R12 |
| 2 | BC857C | Package_TO_SOT_SMD:SOT-23 | Q1, Q5 |
| 2 | SK24A | rt_diodes:D_SMA | D3, D6 |
| 1 | 18V | Package_TO_SOT_SMD:SOT-23 | D2 |
| 1 | 330 | Resistor_SMD:R_0603_1608Metric | R8 |
| 1 | 4k7 | Resistor_SMD:R_0603_1608Metric | R3 |
| 1 | ATTINY85-S | Package_SO:SOIC-8_5.23x5.23mm_P1.27mm | U3 |
| 1 | BAT54A | Package_TO_SOT_SMD:SOT-23 | D5 |
| 1 | BSS138 | Package_TO_SOT_SMD:SOT-23 | Q2 |
| 1 | CONN_01X06 | rt_Pin_Header:Pin_Header_Straight_1x06_2.00_Pitch | P4 |
| 1 | FB | Inductor_SMD:L_0603_1608Metric | FB1 |
| 1 | LOGO | rt_Logos:Helena_5,0x4,1mm | G*** |
| 1 | MCP1703CB | Package_TO_SOT_SMD:SOT-23W | U2 |
| 1 | MCP6482 | Package_SO:MSOP-8_3x3mm_P0.65mm | U1 |
The 57 most common of 59 parts.
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Questions
How big is the Helena base sd PCB?
It measures 22.1 × 18 mm and has 2 copper layers, 0.8 mm thick.
What parts does the Helena base sd use?
59 parts, built around the MCP6482-E/MS, IRLML0030, BC857C and SK24A. 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 Helena base sd KiCad files?
From the Reisi/Helena repository on GitHub, at the commit this page was made from: the board is Hardware/Base_Step_down/Helena_base_sd.kicad_pcb and its schematic Hardware/LED_Boards/XHP35_XHP50_KD2/XHP35_XHP50_KD2.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Helena base sd design in my own project?
Its repository publishes it under the BSD-2-Clause licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).