Man robbed twice on city streets.
During the first attack Christopher Dervan forced the victim to go to a cash point and withdraw PS10.
At Birmingham Crown Court, Judge James Burbidge QC told Dervan: "You took that victim, who had precious little money, to the cash point and made him withdraw the only PS10 he had left in the world at that stage."
Dervan, 34, of The Worthings, Stirchley, admitted two charges of robbery.
Helena Miller, prosecuting, said on February 15 the victim was approached by Dervan who made as if he had a knife and forced him to go to a cash point.
On February 25 the victim left a pub in Kings Heath when he came across Dervan again and was made to hand over his mobile phone.
Dervan waited for police after the second robbery.