Ryan Cooper was banned from contacting his father for two years by Mansfield Family Court in October 2022, said prosecutor Annelli Pritchard.
He attended his dad’s home on May 24 last year and made 'delusional comments' but left without causing any issues.
Five days earlier he rang the doorbell and when he got no answer he posted a letter addressed to his dad.
"This is a deliberate breach," said Ms Pritchard.
"He has gone there knowing he shouldn't, but the harm is limited."
The court heard Cooper has 'a number of previous convictions' and most recently failed to comply with a community order.
His defence solicitor said he deserved credit for his early guilty plea and cooperated with the police from the outset.
"He turned up looking distressed," she said.
"There is no violence, or threats or damage. He didn't stay there after he was asked to leave.
"He really does regret that this happened. He wasn't in the right frame of mind.”
She said Cooper, who suffers from mental health issues, would benefit from a thinking skills programme.
But a probation officer told the court that would have no impact until his mental health issues are addressed.
Cooper, aged 41, of Valentine Avenue, Selston, admitted breaching the order twice when he appeared at Nottingham Magistrates Court on Wednesday.
The case was adjourned until May 29.
He was bailed on condition he abides by the non-molestation order.