"I'm ready to die, I want to die," one of the entries said.
In another entry he wrote about the impending date and time of his planned death, and gave detailed descriptions of what he needed to do to carry it out.
On September 30, 2014, he wrote about how it was nearly time to get started on his "mission".
"Just waiting for 10.30 now and that's it, D day."
Antipas' body was found by a prison officer in the early hours of October 1.
Speaking to the coroner, Antipas' mother today said he was "overcharged with a lack of evidence, and this was a great burden to him".
"We have never known Johnny to be so angry, so hurt, and so distressed," she said.
Johnny died innocent, of course, because those charges were never proved, yet the system treated him as being guilty before being proven.
The family believed he had been set up by the alleged kidnapping victim, and Antipas believed his charges to be "unjust".
"His imprisonment crushed him completely . . . getting bail was so important to him but the bail was denied."
She said Antipas was a polite, considerate, kind-hearted person, and a good father who loved his children.
"Johnny died innocent, of course, because those charges were never proved, yet the system treated him as being guilty before being proven."
She said Antipas' charges "gave him a sense of hopelessness".
Chris Burns, who was the prison director in 2014, said Antipas was not assessed as being at risk of suicide, and did not alert staff to any distress after his latest court hearing.
However, it later came to staff attention that Antipas had spoken of harming himself. But during an assessment he did not exhibit any behaviours that would have prompted him to be categorised as at risk, Burns said.
Had Antipas' cell been searched, his diary could have been briefly reviewed, giving staff an indication of his plans, Burns said.
"However, I'm also minded that a prisoner should be afforded some privacy where possible."
Coroner Peter Ryan has made a preliminary finding that Antipas' death was self-inflicted.
The hearing continues.