Solar flares do NOT affect the devices on the ground. All the fast-moving charged particles are completely absorbed in the upper atmosphere. And to give you some perspective, the most energetic flares can produce 10^-3 W/m^2 flux at the Earth's orbit.
The flares do affect the geomagnetic field. And a changing magnetic field induces current, but it becomes non-negligible only for very long conductors. So long-distance power transmission lines might suddenly become biased with a persistent DC voltage, and some long optical cables might start experiencing over/undervoltage problems with amplifiers.
But locally? You won't see anything unusual.