4 layers65 × 56.1 mm
2 layers46 × 68 mm
Tachoconverter
roberto314/SpeedoCableReplaceAn electronic replacement for a Speedometer Cable from an old car.
- Size
- 46 × 68 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 33
- Nets
- 48
- Pads
- 135
- Tracks, vias
- 319, 2
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 25 Apr 2024
- Updated
- 22 Jun 2024
Overview
Tachoconverter is an open-source printed circuit board by roberto314, from the roberto314/SpeedoCableReplace repository on GitHub, published under the BSD-2-Clause licence. It is a 2-layer board of 46 × 68 mm with 33 parts on 48 nets, routed with 319 tracks and 2 vias.
It is built around the 74HC14, AT24CS64-SSHM-B and L7805, with the BAV99 among its other parts. Its parts include 10 connectors, 6 resistors, 4 capacitors, 3 ICs and 2 diodes.
Main components
4
74HC14
SOP-14-40℃~+85℃ 1.9V、3.98V、4.4V、5.48V、5.9V 100mV、260mV、260mV 20uA 25ns@4.5V,50pF 2V~6V 6 74HC Noise suppression function Schmitt trigger SOP-14 Inverters ROHSJSMSEMIInverters
AT24CS64-SSHM-B
SOIC-8-40℃~+85℃ 1,000,000 cycles 1.7V~5.5V 100 years 1MHz 3mA 5ms 64Kbit 6uA 900ns Hardware write protection function、Noise suppression function、Built-in power-on reset (POR) I2C SOIC-8 EEPROM ROHSMicrochip TechnologyEEPROM
L7805
TO-220ST0℃~+125℃@(Tj) 1 1.2A 20V 2V@(1A) 42uV 500uA 5V 73dB@(120Hz) Fixed Positive Short Circuit Protection TO-220ST Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSOSENVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
BAV99
SOT-231 Pair Series Connection 1.25V@150mA 100V 215mA 250mW 4A 4ns 500nA@80V SOT-23 Switching Diodes ROHSNexperiaSwitching Diodes
README
README.mdSpeedoCableReplace
An electronic replacement for a Speedometer Cable from an old car.
This is a simple solution for a broken speedometer cable. It uses a sensor on the wheels or on the propshaft and converts it to a PWM for a small BLDC Motor. I found some on ebay. They look like this:
This motor should be mounted to the speedometer. The microcontroller is a STM32F103 maple mini board. The firmware is based on ChibiOS 20 (trunk).
Schematic:
Parts
33| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | Conn_01x01 | Connector_PinHeader_2.54mm:PinHeader_1x01_P2.54mm_Vertical | J4, J7, J8, J9 |
| 4 | MountingHole | MountingHole:MountingHole_3.2mm_M3 | H1, H2, H3, H4 |
| 3 | 10k | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R2, R3, R4 |
| 3 | 1k | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R1, R5, R6 |
| 2 | 100n | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C2, C4 |
| 2 | 100u/25 | Capacitor_Tantalum_SMD:CP_EIA-7343-31_Kemet-D | C1, C3 |
| 1 | 1N4007 | Diode_SMD:D_SMA | D1 |
| 1 | 74HC14 | Package_SO:SOIC-14_3.9x8.7mm_P1.27mm | U5 |
| 1 | AT24CS64-SSHM | Package_DIP:DIP-8_W7.62mm_Socket_LongPads | U1 |
| 1 | BAV99 | Package_TO_SOT_SMD:SOT-23_Handsoldering | D2 |
| 1 | Conn_01x02 | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J5 |
| 1 | Conn_01x05 | Connector_PinHeader_2.54mm:PinHeader_1x05_P2.54mm_Vertical | J10 |
| 1 | Conn_01x07 | Connector_PinHeader_2.54mm:PinHeader_1x07_P2.54mm_Vertical | J6 |
| 1 | HC05 | Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Vertical | J2 |
| 1 | Input | TerminalBlock_MetzConnect:TerminalBlock_MetzConnect_Type094_RT03505HBLU_1x05_P5.00mm_Horizontal | J3 |
| 1 | L7805 | Package_TO_SOT_THT:TO-220-3_Vertical | U2 |
| 1 | Maple_Mini | Module:Maple_Mini | A1 |
| 1 | Motor | TerminalBlock_MetzConnect:TerminalBlock_MetzConnect_Type094_RT03505HBLU_1x05_P5.00mm_Horizontal | J1 |
| 1 | SensorPullup | Jumper:SolderJumper-2_P1.3mm_Bridged_RoundedPad1.0x1.5mm | JP2 |
| 1 | SensorVcc | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | JP1 |
| 1 | WP | Jumper:SolderJumper-2_P1.3mm_Bridged_RoundedPad1.0x1.5mm | JP3 |
Questions
How big is the Tachoconverter PCB?
It measures 46 × 68 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Tachoconverter use?
33 parts, built around the 74HC14, AT24CS64-SSHM-B, L7805 and BAV99. 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 Tachoconverter KiCad files?
From the roberto314/SpeedoCableReplace repository on GitHub, at the commit this page was made from: the board is schematics/Tachoconverter.kicad_pcb and its schematic schematics/Tachoconverter.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Tachoconverter 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).
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