Beadle had been seeking new employers following his release from Bristol City at the end of last season and failed to clinch a contract with Third Division Cheltenham Town last week.
He linked up with The Bees and impressed during the pre-season friendly against Farnborough Town last Saturday.
The 31-year-old's display has earned him a month's contract with the Second Division outfit.
Beadle is in line for his Bees debut on Saturday against Tranmere and he is grateful for the chance to play first-team football.
"The most important thing for me was that I get playing and training again," Beadle told the club's official website.
"I felt that I did well in the Farnborough game."
