In most cases there are two levels of proposal. The first being the single sentence concept of the project proposal. Rather than use a real world example, we will use a fanciful one that describes the design of the perfect pet.
The concept sentence might be this. Design and build a prototype for a pet that does not shed, eat or eliminate waste.
The next step is a considered logic plan. What must be accomplished to reach that design concept. In this step, you can either propose questions that must be answered or add design steps. These should be bulletized in a single item per step manner. In our case, these might be the points for the design.
- Will it have fur?
- Will it walk?
- Design it small enough to carry.
- Design it so it does not have an odor.
- Make it loyal to its owner.
- Built in theft alarm.
- Four legs for stability.
- Battery or main power?
- Command control by voice, pointing or clapping.
There could be many more of these design points but for this tutorial, we will consider one of these design points for continuing our process. Let's take item 7 for example. A four legged creature matches what we see in nature and it will be a very strong and speedy pet with four legs. But is that the most stable design? In nature, four legs requires extraordinary control and coordination. Humans have 4 limbs which we use nimbly but only after a lifetime of practice. Dogs, cats and horses have four limbs which must be used in a precisely coordinated effort to run, jump and play. But consider the milking stool. They are designed with tree legs because stability on uneven ground is critical to the comfort of the farmer milking a cow. So the question becomes one of a conceptual decision. Four legs or three?
Because any good design is fluid all the way from concept to final product, it is perfectly acceptable to ask and re-ask questions like this throughout the design process. When we are selecting the motive power for the design of "Pet 1.0," we might choose a motor, muscle wire or springs under tension to create motion. Those will all affect the final design and must be considered equally. Cost, strength or versatility might impact the decision which will ultimately help in deciding four legs or three.
After you decide on the configuration and design of each item, you then define the steps needed to complete the task. At this point, you are not choosing such things as which transistor to use but a more general description of your design function. Using number 7 yet again, here is a typical method.
7. Design a four legged device using 4 independent motors, gears, pulleys and mechanical internal rigid components that allows each limb to mimic the limbs of a dog. Each limb will be able to independently operate over the full range of movement that a dog would have. All four limbs would be coordinated to perform such tasks as walking, running and other dexterous actions as required by being controlled by a central computer or program within a computer.
Each of the above steps in the concept must be developed similarly. Remember to avoid using specifics. You might have in mind to use a specific control computer for this design which is perfect. Then you might find another design that is better. At this stage in the design proposal, it would be a shame to eliminate a future development because you limited your choices too early. Motor control by an H-Bridge using discrete components might not be as efficient as using an Integrated Circuit H-Bridge. Keep your options open until the very last possible point. But we're still a long way from the actual design. This tutorial is for a design proposal at this point. After you finish the entire proposal, it is time to start picking it to pieces. And that will be the subject of another tutorial.
For now, realize that this is not the proposal that we are looking for on our Proposals page. This is your internal document that will be used in your project collaboration which is the first step after a proposal is approved for design.
In reality, with all the fine cats, dogs and horses available to us today, I would probably knock back a proposal like this unless it had some unique merit to the project beyond just being another lap pet.