A pressure sensor assembly for a syringe pump, the pressure sensor assembly comprising: a plunger comprising: a sensing surface, the sensing surface having an elongated portion along a first axis and a width along a second axis, the first and second axes (B, A) are orthogonal relative to each other, wherein the width is about constant along a substantial portion of elongated portion, wherein the elongated portion of the sensing surface defines first and second ends, wherein the first and second ends are curved; a first extension disposed adjacent to or on the first end of the sensing surface and extending along a third axis orthogonal to the first and second axes away from sensing surface, wherein the third axis is a longitudinal axis of the first extension; and a second extension disposed adjacent to or on the second end of the sensing surface and extending along a fourth axis orthogonal to the first and second axes away from sensing surface, wherein the fourth axis is a longitudinal axis of the second extension and wherein the third and fourth axes are parallel to each other; a guide configured to guide the movement of the plunger along the third and fourth axes; a first pressure sensor disposed adjacent to an end of the first extension opposite to the sensing surface, the first pressure sensor is configured to sense movement of the plunger within the guide; and a second pressure sensor disposed adjacent to an end of the second extension opposite to the sensing surface, the second pressure sensor is configured to sense movement of the plunger within the guide. a plunger comprising: a sensing surface, the sensing surface having an elongated portion along a first axis and a width along a second axis, the first and second axes (B, A) are orthogonal relative to each other, wherein the width is about constant along a substantial portion of elongated portion, wherein the elongated portion of the sensing surface defines first and second ends, wherein the first and second ends are curved; a first extension disposed adjacent to or on the first end of the sensing surface and extending along a third axis orthogonal to the first and second axes away from sensing surface, wherein the third axis is a longitudinal axis of the first extension; and a second extension disposed adjacent to or on the second end of the sensing surface and extending along a fourth axis orthogonal to the first and second axes away from sensing surface, wherein the fourth axis is a longitudinal axis of the second extension and wherein the third and fourth axes are parallel to each other; a sensing surface, the sensing surface having an elongated portion along a first axis and a width along a second axis, the first and second axes (B, A) are orthogonal relative to each other, wherein the width is about constant along a substantial portion of elongated portion, wherein the elongated portion of the sensing surface defines first and second ends, wherein the first and second ends are curved; a first extension disposed adjacent to or on the first end of the sensing surface and extending along a third axis orthogonal to the first and second axes away from sensing surface, wherein the third axis is a longitudinal axis of the first extension; and a second extension disposed adjacent to or on the second end of the sensing surface and extending along a fourth axis orthogonal to the first and second axes away from sensing surface, wherein the fourth axis is a longitudinal axis of the second extension and wherein the third and fourth axes are parallel to each other; a guide configured to guide the movement of the plunger along the third and fourth axes; a first pressure sensor disposed adjacent to an end of the first extension opposite to the sensing surface, the first pressure sensor is configured to sense movement of the plunger within the guide; and a second pressure sensor disposed adjacent to an end of the second extension opposite to the sensing surface, the second pressure sensor is configured to sense movement of the plunger within the guide.