To explain the chip, I will use one of the simplest circuits, an oscillator that cycles on and off at a fixed frequency. Just as an aside, the FDS4559 is a pair of about 3 amp MOSFETs in the same package, one P channel and one N channel for less than a dollar in onesies at DigiKey. The 555 timer IC is an 8 pin integrated circuit used in a variety of timer, pulse generation, and oscillator applications. The 555 was originally designed in 1971 by Hans Camenzind, a Swiss electronics engineer employed by Signetics in. The 555 chip is extremely versatile with hundreds of applications from a timer or latch to a voltage-controlled oscillator or modulator. As shown in the circuit schematic diagram, the 555 timer is wired. A classic for all of those first year circuits projects to blink an LED, buzzer etc.1. The main electronic component for the capacitive touch sensor circuit is the 555 timer IC. The LTspice circuit list is here if you want to play with the circuit, and if you want to switch to a low side driver get rid of Q1B and replace R6 with the motor and D2. Timer IC - This is a common 555 timer/oscillator from TI. The circuit shown below assumes you're stuck with a high side driver, and it'll work with a bipolar 555. If you use a P channel MOSFET with a reasonable Rds(on) for the high side driver then you'll get nearly all of the 5V supply across the motor when the MOSFET turns on, plus it'll dissipate very little power. The emitter follower you've shown is better, but you can't drive it into saturation so you'll still lose about a volt across the transistor when it's on, starving your motor somewhat. As a high side driver, the 555 is only rated for something like 100 mA, and it takes a good sized output voltage hit at that current, so it'll never work directly as a motor driver.

555 timer chip