6 layers50 × 85 mm
2 layers15 × 10 mm
Magnetic switch
miket6000/SimpleSwitch1A magnetic power switch for use in rocketry
- Size
- 15 × 10 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 20
- Nets
- 15
- Pads
- 59
- Tracks, vias
- 85, 10
- Pours
- 4
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 6 Dec 2024
- Updated
- 9 Nov 2025
Overview
Magnetic switch is an open-source printed circuit board by miket6000, from the miket6000/SimpleSwitch repository on GitHub, published under the CERN-OHL-W-2.0 licence. It is a 2-layer board of 15 × 10 mm with 20 parts on 15 nets, routed with 85 tracks and 10 vias.
It is built around the SN74AUP1G74DCU, TPS70933DBV and DMP2040UFDF, with the BAT54CT, RUM002N02T2L and XL-1615SURUGC among its other parts. Its parts include 5 resistors, 4 connectors, 3 ICs, 3 transistors and 2 capacitors.
Main components
6
SN74AUP1G74DCU
VSSOP-8-0.5mm-40℃~+85℃ 0ns 1 1 1.5pF 100MHz 4mA 4mA 500nA 500ps 74AUP Series 7ns@3.3V,30pF 800mV~3.6V Complementary type D-Type Rising Edge Set and Reset VSSOP-8-0.5mm Flip Flops ROHSTexas InstrumentsFlip Flops
TPS70933DBV
SOT-23-5-40℃~+125℃@(Tj) 1 1.4uA 150mA 190uVrms 3.3V 30V 80dB@(10Hz) 960mV@(150mA) Fixed Over Current Protection、Thermal shutdown、Enable control、Input under-voltage protection、Reverse-polarity current protection Positive SOT-23-5 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSTexas InstrumentsVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
DMP2040UFDF
UDFN2020-6-55℃~+150℃ 1 P-Channel 1.5V 1.8W 105pF 13A 20V 32mΩ@4.5V 8.6nC@4.5V 834pF UDFN2020-6 MOSFETs ROHSDiodes IncorporatedMOSFETs
BAT54CT
SOT-523-31 Pair Common Cathode 1V@100mA 200mA 2uA@25V 30V 600mA SOT-523-3 Schottky Diodes ROHSJiangsu Changjing Electronics Technology (CJ)Schottky Diodes
RUM002N02T2L
SOT-723-55℃~+150℃ 1 N-channel 10pF 10pF 150mW 1V 2.4Ω@1.5V 200mA 20V 25pF N-Channel SOT-723 MOSFETs ROHSROHM SemiconductorMOSFETsXL-1615SURUGC
SMD-4P,1.6x1.5mm-40℃~+85℃ 1.6mm x 1.5mm square LED 120° 180mcd、1.2cd 2.4V、3.4V 20mA 50mW、70mW 520nm~530nm、620nm~630nm 525nm、625nm Discrete Diode Red, Emerald Green Top-mount Water Clear SMD-4P,1.6x1.5mm LED Indication - Discrete ROHSXINGLIGHTLED Indication - Discrete
README
README.mdSimpleSwitch
SimpleSwitch is a magneticly operated electronic switch designed for model rocketry. It is a 15x10mm PCB with an input and output capable of switching approximately 4A continuous and 10A for 10s. It can accept an input voltage of up to 12V and also includes reverse polarity protection to prevent damage to the switch or downstream electronics in the event that the battery is accidentally connected backwards.
It is designed specifically to be easy to turn on, but to require multiple steps to turn off. This is to prevent issues with accidental turn off which can occur with traditional magnetic switches when they pass by magnatized hardware on launch towers/rails.
The magnetic switch draws a very small amount of power from the battery when plugged in. This is calculated at 3uA worst case, so a small 150mAh 1s battery should last approximately 5 years. On larger batteries this is quickly swamped by the batteries self discharge rate.
Operation
Use of the SimpleSwitch is easy. Bringing a magnetic south pole near the top of the board will result in the switch turning on and illuminating both the red and green LEDs, the switch is now in the "ON" state.
To turn off the switch you nead to put a North pole near the switch which will cause the red LED to turn off ("OK" state). Bringing a South pole near the switch will then cause the green LED to turn off and the red LED to turn back on ("WARNING" State). One more north pole will cause the red LED to turn off and the switch to disable the output ("OFF" State).
In summary as you alernate South->North->South->North you step through the states as shown below:
| Magnetic Pole | State Name | Red LED | Green LED | Switch State |
|---|---|---|---|---|
| OFF | OFF | OFF | OFF | |
| SOUTH | ON | ON | ON | ON |
| NORTH | OK | OFF | ON | ON |
| SOUTH | WARNING | ON | OFF | ON |
| NORTH | OFF | OFF | OFF | OFF |
Parts
20| Qty | Value | Footprint | References |
|---|---|---|---|
| 3 | 100k | Resistor_SMD:R_0402_1005Metric | R1, R5, R6 |
| 2 | DMP2040UFDF | Package_TO_SOT_SMD:Vishay_PowerPAK_SC70-6L_Single | Q1, Q3 |
| 1 | 100 | Resistor_SMD:R_0402_1005Metric | R4 |
| 1 | 100n | Capacitor_SMD:C_0402_1005Metric | C2 |
| 1 | 1k | Resistor_SMD:R_0402_1005Metric | R2 |
| 1 | 2u2 | Capacitor_SMD:C_0402_1005Metric | C1 |
| 1 | BAT54CT | Package_TO_SOT_SMD:SOT-523 | D3 |
| 1 | DRV5012 | Footprints:X2SON_4_EP | U1 |
| 1 | GND_IN | Footprints:WireSolderPad_w_hole | J2 |
| 1 | GND_OUT | Footprints:WireSolderPad_w_hole | J4 |
| 1 | MountingHole_Pad | MountingHole:MountingHole_2.2mm_M2_DIN965_Pad | H1 |
| 1 | RUM002N02T2L | Package_TO_SOT_SMD:SOT-723 | Q4 |
| 1 | SN74AUP1G74 | Package_SON:X2SON-8_1.4x1mm_P0.35mm | U4 |
| 1 | TPS70933 | Package_TO_SOT_SMD:SOT-23-5 | U3 |
| 1 | V_IN | Footprints:WireSolderPad_w_hole | J1 |
| 1 | V_OUT | Footprints:WireSolderPad_w_hole | J3 |
| 1 | XL-1615SURUGC | Footprints:LED_SMT_DUAL_1615 | D1 |
Questions
How big is the Magnetic switch PCB?
It measures 15 × 10 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Magnetic switch use?
20 parts, built around the SN74AUP1G74DCU, TPS70933DBV, DMP2040UFDF and BAT54CT. 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 Magnetic switch KiCad files?
From the miket6000/SimpleSwitch repository on GitHub, at the commit this page was made from: the board is hardware/magnetic_switch.kicad_pcb and its schematic hardware/magnetic_switch.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Magnetic switch design in my own project?
Its repository publishes it under the CERN-OHL-W-2.0 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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