rtcwake in a cron job

[Phil]

Thank you for reading this.

I'm attempting to wake my computer from hibernation when a cron job is 
activated.

I've simplified the shell script as follows:

#!/bin/bash
now=$(date +%s)
rtcwake -m no -t now

I've tried all sorts of schemes but I'm still not getting the time in 
the correct format to hand to rtcwake.

rtcwake: failed to parse time_t value: 'now'

Can anyone tell me how to get the correct time_t format from date?

-- 
Regards,
Phil