there is another way, dunno if it'll do though.
you can use qtc pills or pipe as the sensor, essentially these are resistors whose resistance changes as pressure is applied to them. you could use them in a voltage divider, feed the output to an adc in your ucontroller. Its cheaper than admins option but you'll need to design the lot yourself and i dont think it'll be as accurate as using admins option.
but hey, you get what you pay for