I'm currently doing a project that consists of:

  1. Arduino Nano.
  2. Battery.
  3. Buck Boost converter.
  4. GPS module.
  5. TSL2561 light sensor.
  6. BH1750FVI light sensors.
  7. LSM6DS3 Accelerometer.
  8. HDC1080.
  9. MicroSD shield with microSD

All of the sensors are I2C based, GPS is UART and SD card is SPI.

My question is:

I'm planning to place the components inside a wooden box and mount the box to the top of the car roof with neodymium magnets so it is movable around the vehicle roof top for the measurement.

Will the wood box be sufficient to stop the magnetic fields produced by the neodymium magnets (for mounting) from interfering (if there is going to be any) with the components that are connected to the PCB board?

  • \$\begingroup\$ The GPS are transmitting magnetic direction? If so, your magnets will interfere with the measuring \$\endgroup\$ – José Manuel Ramos Nov 16 '18 at 8:03
  • \$\begingroup\$ The GPS is used for position logging for every measurement \$\endgroup\$ – Richu Nov 16 '18 at 8:07
  • \$\begingroup\$ Are the magnets moving around the wooden box? \$\endgroup\$ – José Manuel Ramos Nov 16 '18 at 8:09
  • \$\begingroup\$ The neodymium? No, it is just there to hold the box in place mounting the box to the car roof top \$\endgroup\$ – Richu Nov 16 '18 at 8:16
  • \$\begingroup\$ If everything is hold firmly, there isn't any inducted current (in theory) and, therefore, the magnets will not affect your circuitry with noticeable currents (maybe nA). The I2C and UART are secure with uA noise moving around. \$\endgroup\$ – José Manuel Ramos Nov 16 '18 at 8:25

None of the listed parts are sensitive to magnetic fields, so the mere presence of the magnet shouldn't bother them at all.

The sensors and magnets will be physically attached to the box, and so must move together. To induce current, the conductor and the magnet must move at different speeds. Since they are all attached to the box, all the parts will be subject to the same motion - no induced current, no problem.

The LSM6DS3 has provision to connect an external magnetometer, but you don't mention having one in your project. If you do have a magnetometer attached, things get more complicated. Probably better to use suction cups for mounting the box in that case.

Vibration could cause some low currents to be induced in your traces and wiring. Vibration can do this because the parts aren't perfectly rigidly attached to the box and will therefore move a tiny bit in relation to each other.

That shouldn't be enough to bother any of the circuits you mentioned.

The wooden box will have pretty much no noticeable effect on the magnetic field. About all it gives you is a little more distance from the magnet - which by itself reduces the strength of the field when it reaches your parts. But, the wood itself doesn't really matter - it might as well be air for all the difference it would make.

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  • \$\begingroup\$ Stationary magnets can have an effect on inductors, which are present on this build. The field is equivalent to having a DC current applied which can lead to core saturation. \$\endgroup\$ – Edgar Brown Nov 16 '18 at 14:53

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