ColeslawNicks

I am designing my own Charpy impact testing machine and I am unsure what would be the best as well as relatively simple and affordable method I can use to accurately measure the angle the pendulum travels after it has broke the sample. I would also appreciate any complex and more expensive ideas too that I can consider, accuracy and reliability are the most important things. I have thought of some methods but a lot of them will cause friction against the pendulum which could over complicate the final calculations. For anyone that is not familiar with the Charpy method here is a link to a brief description: http://www.twi.co.uk/services/technical-information/faqs/material-faqs/faq-what-is-charpy-testing/ Thanks.