This video demonstrates a simple setup for using altimeter deployment for rocket motors that do not have a delay/ejection element. Links to some of the supplies I used below:

Altimeter sled is part of this rocket: https://www.thingiverse.com/thing:288...
Thanks TurbulentSphere!

E-Matches: https://csrocketry.com/recovery-suppl...

RRC2+ Altimeter: https://www.missileworks.com/store/#!...

Eggtimer Appogee: http://eggtimerrocketry.com/apogee_faqs/

Amazon Affiliate Links:
Centrifuge Vials: https://amzn.to/3OvxVy8
Kevlar String: https://amzn.to/3jWcyrL
9V Batteries: https://amzn.to/3L3y6yv
Stranded Wire: https://amzn.to/3Ox0E5M (better than speaker wire)