We propose a spoof localized surface plasmon (SLSP) resonator which is composed of single-layer concentric inward and outward spoke patterns to reach strong confinements of electromagnetic waves. By introducing a slit perturbation to break the in-plane symmetry, the confinement is double-folded and the radiation loss is further suppressed. Based on this deep-subwavelength and ultra-sensitive SLSP resonator, a real-time sensing circuit is designed and fabricated with a micro-controller unit (MCU). This work envisions the prospective applications of SLSPs in compact and portable sensing systems.