May customer pumasok dito with a robotic arm project. Tapos na yung code, tapos na yung wiring, pero yung SG90 servo tuloy-tuloy yung kembot kahit dapat naka-stop na. Eto yung apat na bagay na pinagchecheck ko bago ma-blame yung servo.
Una, power. Pinakamadalas na sanhi nito. Pag galing sa Arduino's 5V pin yung servo, kulang yung supply. Yung onboard regulator ng Arduino kaya niya yung MCU pero hindi yung sudden current draw ng motor — voltage dips, "brown out" yung servo mid-movement, mukhang jitter siya. Solution: separate 5V supply for the servo. Battery pack or wall adapter. Bigyan mo ng common GND with the Arduino, otherwise wala ka pang nasolve.
Pangalawa, common ground. Kahit separate na yung supply, kelangan magkadikit pa rin yung GND pins. Walang common ground = signal noise = jitter. Tinatamad ko nga lagi i-mention pero madalas talaga ito yung issue.
Pangatlo, decoupling cap. 100µF electrolytic + 0.1µF ceramic across yung servo's V+ and GND. Sumasalo siya ng yung mga current spikes pag bigla nag-accelerate yung motor. Mga PHP 5 yung components, malaki yung effect.
Pang-apat, signal cleanliness. Mahabang jumper wires sa breadboard pulls noise. Subukan mong ipalitan ng mas maikli, or twist mo together yung signal at GND wires (poor man's twisted pair). Sa robotics projects na maraming gusot, pag dinatnan ka ng noise issue mahirap mag-debug.
Apat na yan tapos jitter pa rin? Then maybe sira na talaga yung servo. Pero in my experience, yung first three covers parang 90% of cases. Ano pa ginagawa niyo for jittery servos?
Servo motor keeps jittering even at rest — 4 things I check before blaming the servo
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circuitrocks
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jm_robotics
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Confirmed yung decoupling cap fix from competition robotics experience. Niligtas niyan yung line-follower namin last season — yung dalawang MG90s sa front jumitter nonstop, halos sumuko na ako bago ako naglagay ng 220µF + 0.1µF across each servo's power input. Suddenly stable.
Isa pang bagay worth mentioning kung 4+ servos yung dini-drive mo: a PCA9685 PWM driver (16-channel I²C breakout) gives you cleaner PWM signals than the Arduino directly. Yung Arduino's PWM pins, timer-shared with other functions, so signal quality varies depending sa kung ano pa ang umaandar. Dedicated hardware lang yung PCA9685 for PWM. For sumo bots though, 1-2 servos OK na walang yan.
Quality of the servo itself matters din — yung mga pinakamurang SG90s vary big-time. Worth paying more for the better-rated ones kung jitter is critical sa project mo.
Isa pang bagay worth mentioning kung 4+ servos yung dini-drive mo: a PCA9685 PWM driver (16-channel I²C breakout) gives you cleaner PWM signals than the Arduino directly. Yung Arduino's PWM pins, timer-shared with other functions, so signal quality varies depending sa kung ano pa ang umaandar. Dedicated hardware lang yung PCA9685 for PWM. For sumo bots though, 1-2 servos OK na walang yan.
Quality of the servo itself matters din — yung mga pinakamurang SG90s vary big-time. Worth paying more for the better-rated ones kung jitter is critical sa project mo.