Hi – I’m Jude and I'm a Design Engineer. I've worked on a range of projects for a variety of companies in different countries - and in many cases we use pretty humble materials to make quick models to communicate and test ideas.
Often in the early stages of a creative process, CAD and Rapid Prototyping can take too long (and might be too expensive for mistakes!) so I wanted to share some techniques that although look simple have a lot of subtle tricks.... As with watching a fancy Chef on TV, they often skim over the details that took them years to master - which may explain why when you try it it's never that easy!
The cardboard Raspberry Pi Case example is not meant to be exhaustive or a final model – indeed, it assumes that you should iron-out the main functionality and aesthetics and then progress with confidence into more serious materials/CAD. The number of iterations is up to you - some might be straightforward, while others can take numerous revisions discussing details with users, manufacturers, etc. though conversations are more productive if you can feel and modify how a product works in front of you.
Just as ‘a sketch says a thousand words’, one could extend that to say a physical model says a thousand sketches… but as with both skills, they should be used appropriately and of course they take some time to perfect. I’m still learning a lot, but hope you in enjoy a few tricks I’ve picked up along the way… (An Instructables Guide of all techniques and more is also being made too!)
Note: A video tutorial of of this was initially done here, but I'm keen to see what you think of it in the Instructables format. Please check out both and let me know what you think!
FEATURES OF MY DESIGN
Your Raspberry Pi won't get that hot - but it will certainly not help it to run a movie - while fully air sealed. This was also an opportunity to make a design out of this feature, using an unlikely material - cocktail sticks.
2. Light Pipes
This is a very common technique used in design - where for economy you want the lights (LEDs) mounted on a circuit board, but the board is positioned away from the case or user-interface. By taking a piece of clear plastic, one can 'bounce' the light along it (because of refraction) over some distance. Here I will show you how to do this for yourself.
Experiement as you go - you might see things I've missed and want to change them!
Step 1: Sketch Some Ideas for Your Case
I considered 6 different grill styles for the case - which not only gave ventilation to printed circuit board (PCB) - but also made a feature of the lights (LEDS) on the board.
I then considered a rounded case or a square-edged case. I selected the square one for simplicity at this stage, but as you can see in other tips, it could be easily rounded too.
Step 2: Make Rough Models or Things You Are Unsure About
Keep experimenting until you are happy.
Step 3: Create a Template (net) for the Case
Step 4: Creating an Accurate Cardboard Joint
Step 5: Creating the Grill (with Cocktail Sticks)
Step 6: Light Pipes
Next take some clear plastic sheet (about 2mm thick) and cut into the sizes as shown. This may require some fiddly cutting and snapping with pliers as shown - please check out this video if you have not done this before, here.
As shown in the final picture - check to see that the light is transmitted effectively, by hovering it over the PCB.
Step 7: Awesome Super-Glue Tip
Similarly using insulation tape when constructing large assemblies (that are perhaps in tension) is ideal, as the tape can be pulled off easily once everything is glued in place.
Here it is used as a surface to take small amounts off of with a cocktail stick to apply in small quantities to glue the light pipes in. The advantage is that the superglue is not absorbent and prevents it drying quickly (compared to if it were on a scrap of paper).
Step 8: Main Assembly
Step 9: Power-up!
Thanks for taking a look at this Instructable. I hope you enjoyed it and let me know how this compares to the video here.