Magnetic switch
Our magnetic switch is a step up from your average mag switch.
The sensitive magnet sensor actions a state change after you hold a magnet near it for 2 seconds.
If you turn the device on it will give 5 short beeps to let you know it's on and turn on the onboard LED.
When the device turns off a long single tone will sound.
While turned on the buzzer will give a short beep every 10 seconds so you can listen to your rocket and know your switch is on.
The magnetic switch saves it's state in non volatile memory so any short power outages will not reset the switch and power will remain ON or OFF once restored.
We've also included two decently sized capacitors that can power the onboard microcontroller for 10 seconds to avoid it shutting down at all during short power loss events.
Furthermore, there is a onboard button that you can use to action the switches state change instead of a magnet. There is also a input connection point that you can use with a 3 to 12 volt input signal to action the switch (a 3.3V output point is available to connect a external push button to this point). You can also program the switch yourself if you wish to use it in a different way. The final pin is a UPDI programming connection, you can program using Arduino and the Adafruit UPDI HV Friend board if you fancy a project!
- 10A continuous current.
- Small size 20 x 15mm (~0.78" x 0.59")
- Just 1.1grams weight (~ 0.035 oz)
- Input range of 2.9V to 12V
- OFF mode current of just 4.5uA (About 3.2mah per month!)
- Onboard microcontroller, buzzer for audible indication of state and state LED
- Programmable for custom operation if you require.
- Reverse polarity protection.
- 2oz, 4 layer high quality PCB and full surface mount components.
- State memory. The switch will always return to it's last state after power loss.
- 4x 2.7mm mounting / terminal holes / solder with additional smaller solder holes for maximum installation options.
These MOSFET's have extremely low resistance to avoid generating too much heat and can handle up to 35 Amps temporarily and 10-12 Amps continuously with ease.
The magnet switch sensor is extremely sensitive and actions the device when it detects a magnet present for 2 seconds. This allows you to turn your rocketry electronics on or off using a magnet from outside of your rocket.
If you're using a external push button, you can use the 3V pin and the PB pin to easily connect one.
It runs on a ATtiny816 microcontroller and has a UPDI programming pin available (labelled PR).
We made our program using the Adafruit UPDI HV Friend programmer and Arduino IDE software. The default firmware is below to get you started along with a link to the schematic.
