2 layers130 × 80 mm
2 layers41.9 × 20.3 mm
Pedal assist (PAS) signal generator for electric kick scooters
- Size
- 41.9 × 20.3 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 18
- Nets
- 12
- Pads
- 40
- Tracks, vias
- 54, 0
- Routed
- Yes
- KiCad
- KiCad 5 (file 20171130)
- Created
- 21 Jun 2023
- Updated
- 7 Oct 2025
Overview
PAS is an open-source printed circuit board by ondras12345, from the ondras12345/ebike-PAS repository on GitHub, published under the MIT licence. It is a 2-layer board of 41.9 × 20.3 mm with 18 parts on 12 nets, routed with 54 tracks and 0 vias.
It is built around the ATTINY85-20PU, BAV99 and BC847. Its parts include 5 resistors, 3 connectors, 2 capacitors, 1 IC and 1 diode. It belongs with the AVR (ATmega, ATtiny) boards of this library.
Main components
3
ATTINY85-20PU
PDIP-8-40℃~+85℃ 10bit 2.7V~5.5V 20MHz 512Byte 512Byte 6 8 Bit 8KB AVR Built-in FLASH PDIP-8 Microcontrollers (MCU/MPU/SOC) ROHSMicrochip TechnologyMicrocontrollers (MCU/MPU/SOC)
BAV99
SOT-231 Pair Series Connection 1.25V@150mA 100V 215mA 250mW 4A 4ns 500nA@80V SOT-23 Switching Diodes ROHSNexperiaSwitching DiodesBC847
SOT-231 NPN 100MHz 100mA 100nA 110 200mW 45V 500mV 6V NPN SOT-23 Bipolar (BJT) ROHSShikuesBipolar (BJT)
README
README.mde-bike PAS signal generator
The LD-FXK-038 e-bike controller is often used on electric kick scooters, but those don't have pedals, so you cannot make use of the pedal assist (PAS) feature. This simple device generates a valid pedalling signal to achieve cruise control-like functionality.
Usage
Hold the start button for at least 2 seconds to enable PAS. Start braking to turn it off.
Parts
18| Qty | Value | Footprint | References |
|---|---|---|---|
| 3 | 10k | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R1, R3, R4 |
| 2 | Conn_01x02 | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J1, J2 |
| 1 | 0 | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R5 |
| 1 | 100n | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C1 |
| 1 | 10u / 16V | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C2 |
| 1 | 1k | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R2 |
| 1 | ATtiny85-20PU | Package_DIP:DIP-8_W7.62mm | U1 |
| 1 | BAV99 | Package_TO_SOT_SMD:SOT-23 | D1 |
| 1 | BC847 | Package_TO_SOT_SMD:SOT-23 | Q1 |
| 1 | Conn_01x03 | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J3 |
The 13 most common of 18 parts.
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Questions
How big is the PAS PCB?
It measures 41.9 × 20.3 mm and has 2 copper layers, 1.6 mm thick.
What parts does the PAS use?
18 parts, built around the ATTINY85-20PU, BAV99 and BC847. 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 PAS KiCad files?
From the ondras12345/ebike-PAS repository on GitHub, at the commit this page was made from: the board is PAS.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the PAS 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).