You might could use force sencing resistors like below. https://www.google.com/search?num=100&hl=en&lr=&tbo=d&as_qdr=all&q=fsr+force+sensing+resistor&oq=fsr+resistor&gs_l=serp.1.1.0j0i7j0i7i30j0i7i10i30j0i7i30l3.11644.13365.0.195184.108.40.206.0.0.0.125.207.1j1.2.0.les%3B..0.0...1c.1.nYQNn85f7Gs
Compared to other force sensors, the advantages of FSRs are their size (thickness typically less than 0.5 mm), low cost and good shock resistance. However, FSRs will be damaged if pressure is applied for a longer time period (hours). A disadvantage is their low precision: measurement results may differ 10% and more.