Mirror device used to spy on woman in her bedroom.
The 57-year-old glued the mirror onto the end of a piece of wood then angled it through the window.
A court heard how the man, who cannot be named to protect the identity of his neighbour, watched his neighbour up to three times a day as she dressed and undressed in her bedroom at Pontypridd.
But he was caught when the woman spotted the mirror dangling outside her window.
Prosecutor Ian Kolvin said: "The woman was in her bedroom with her partner when she looked out of the window and saw for the first time a mirror attached to a piece of wood."
Police were called and the neighbour admitted seeing her totally nude twice and in a state of undress more than 30 times.
Mr Kolvin said: "He told police he found her attractive and was pleased if he saw her naked.
"He said he saw her totally nude twice and saw her in her underwear at least 30 times.
"But he maintains there was no sexual gratification."
The court was shown the home-made spying device which the man used for four months at his home in Pontypridd.
Daniel Williams, defending, said: "He is bitterly disappointed at the loss of trust and friendship.
"He appears to be a socially isolated individual and is described as a bit of a loner.
"These are offences that appear to be borne out of curiosity and mischief after staring out of his window for hours on end. His mind wanders."
The man admitted six charges of voyeurismat Newport Crown Court yesterday.
Judge William Gaskell told him: "You used a mirror to look into the private rooms of a female neighbour to watch her while she was undressing and naked.
"This was a breach of trust against your neighbour."
The accused was given a three-year community order to attend a sexual offenders' group programme and ordered to register as a sex offender for five years.