Solenoid Alarm Clock in Series -- Voltage Problems

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We are trying to put a solenoid into series with an alarm clock, in order to go off when the voltage jumps from the alarm going off. However, the voltage varies too much and does not reach a high enough current to power the solenoid.

We used a multi-meter to measure out the range and goes at the highest to around 1.5V. The voltage varies with the pitch of the alarm. When the alarm is not going off, the solenoid is not active. We are actually on an ac voltage, but the Alarm Clock is converting the ac current.
We are looking into this, but it is more than a little confusing. We were thinking that we could amplify the signal, and then use a diode, to keep it from exceeding the max the Solenoid can take (5V).
Transistor as An Amplifier (links)
http://www.st-andrews.ac.uk/~www_pa/Sco ... page1.html
http://www.st-andrews.ac.uk/~www_pa/Sco ... page1.html
The datasheet for the solenoid can be found here.
https://www.sparkfun.com/products/11015
***Any information on how we could attempt to fix this would be appreciated and all used information will be cited along with relevant posts. ***