Kim, the inventor of the “Angel on My Shoulder” Lighted Backpack has been deeply saddened by the many stories young children being hit by cars due to not being easily visible when it becomes dark.  To solve this problem Kim invented a book bag with attachable lighted and reflective wings that could be turned on at night so that children could be more easily seen and hopefully save valuable lives.


Design Goals




  • High-quality reflective material

  • Integration of quality LED lights

  • Discreet Placement of Battery Power

  • Discreet & Easy to Use On / Off Switch

  • Water-resistant Material

  • Attachable / Detachable Wings

  • Attractive Design

  • Affordable




Kim worked with Dirt Cheap Prototypes design team to develop the cut and sew pattern for the attachable wings as well the selection of the led lights, batteries, battery housing, switches and wiring that would be used for the development of the physical prototype for her product.  


BOM Costing


After the design was approved Dirt Cheap Prototypes performed BOM (Bill of Material) Costing Exercises to determine the pricing for the construction of her prototype and manufacturing of her product (including tooling, setup and cost per unit broken down by part.)  After all of this work was completed, pleased with the results, Kim hired Dirt Cheap Prototypes to make a high-quality prototype.




Developing Kim’s prototype, while seemingly simple, involved numerous changes, tweaks, and decisions during the prototype construction process.  Kim was very pleased with the final prototype and is now working on her marketing material and fundraising in hopes of attracting the interest and investment to get her product manufactured.




“Working with DCP has been a very positive experience and I am very pleased with the results of their design, costing and prototyping services.  I recommend Dirt Cheap to anyone looking for complete design and prototyping assistance for their product.  I have also referred a friend to DCP who is also been very pleased with their professionalism and quality of their services.”


Kim C.


Product Development
  • Engineering & Design

  • CAD

  • Physical Prototyping

  • Manufacturing Assistance

  • Focus Groups

Digital Media
  • Virtual Prototyping

  • Website Design

  • Photography

  • Video Production

* - Dirt Cheap Prototypes does not provide patent or marketing services