I need to connect two circuit boards - one with a microcontroller, power circuitry, display, etc to another with several sensors on. The connection will require somewhere between 4-10 lines - 5V power, ground, I2C data and clock, possibly plus some interrupts. The circuit boards will be mounted at right angles with respect to each other.
The crucial problem is that the board with the sensors on will need to move constantly with respect to the board with the microcontroller on. The degree of movement will be small - only a few centimetres, and it will be mainly in one axis (perpendicular to the sensor board, parallel to the microcontroller board). The movement will be irregular in nature - the movement will respond to the sensor input. The movement will be driven by a powerful servo, so the speed and acceleration of the movement may be quite jerky / fast.
So what kind of connection can I use between the boards that will be reliable for this kind of movement? I've seen various kinds of flat flex connection used in consumer products. Is that kind of connection reliable over years of many millions of movements every day? What kind of connection would be used in more reliable applications like automotive or aerospace?