Timed Toothpaste Release Toothbrush CAD Design Needed

I am developing an innovative toothbrush called Time to Brush featuring a timed toothpaste release mechanism designed to encourage users to brush for the recommended duration.

I need an experienced CAD designer or mechanical engineer to create detailed 3D models of:
• A standard manual toothbrush handle
• A brush head with a multi-dose toothpaste chamber
• A simple, low-cost mechanism that releases toothpaste only after about 1–2 minutes of brushing

The design should focus on being affordable, reusable for multiple uses (e.g., 1–2 weeks), and manufacturable with basic prototyping tools like 3D printing.

Key deliverables:
• 3D CAD files suitable for prototyping (STL, STEP, or preferred formats)
• Suggestions for cost-effective time-release mechanisms
• Visual renders for presentations (optional)

Budget: £150–£300
Timeline: 1–2 weeks preferred

Please include examples of previous relevant product designs, your approach to achieving the timed release, and a fixed-price quote.

Looking forward to collaborating with someone passionate about practical, health-focused innovations!