Ryan O'Neal's 26-year-old son Redmond got one hell of a parting gift during his sentencing last week for a probation violation -- a state-of-the-art GPS monitoring bracelet.
Redmond's probation was revoked in September -- after he allegedly snuck out of rehab and ordered drugs on a payphone -- and last week, a judge sent him back to the treatment facility ... with the monitoring device around his ankle.
According to law enforcement sources, the device features real-time cameras that take a snapshot of Redmond's whereabouts every five minutes -- and if he steps outside his assigned area, an alarm goes off.
Redmond -- who's had a long history battling drugs -- pled no contest to drug and weapons charges back in August ... and was sentenced to a year in rehab.
If Redmond screws up again, he faces up to six years in prison.