Barcode Printing on Prescriptions for all hospital department

I have an existing PHP CodeIgniter hospital-management system and I want every prescription we generate to show a machine-readable barcode plus a few extra patient details.

Scope
• Add barcode printing to prescription layouts for OPD, IPD, Pharmacy, Pathology and Radiology.
• Include father’s name and mobile number beside the barcode on each printout.
• On each new prescription, insert a unique key into the patient table so the barcode can instantly pull up that exact visit record.
• Keep all current styling and PDF/print functions intact; no design overhaul needed.

Key points
– The project touches only the prescription module—other modules must remain untouched.
– The codebase is pure CodeIgniter (no HMVC). Please work inside the existing controllers/models/views.
– Any third-party barcode library you add should be open-source and light.
– Deliver clean, commented code plus a quick read-me explaining where files were changed so I can reproduce on staging.

If you’ve added barcode or QR printing to CodeIgniter apps before, this should be a quick job.