Ideally, however, it should be much, much smaller. And that is exactly what I have now invented.
I went through three or four other 'new and improved' designs for the web shooters before finally coming up with this one. Since I'm not actually going to use any of those ones, it would be pointless to explain them here. But I will detail the last two steps of my thought processes.
I realised that I didn't need to have the motors standing on end, nor did I even need two of them. I could simply have a single motor lying flat, and the vertical circular motion of the wheel on the end could be changed into horizontal circular motion by an appropriately oriented gear. That would then be connected to the two wheels that the 'web' gets fed through. They would thus be spun with a single, flat motor.
So, my design at this point was to have the motor on its side, lying across my wrist at the back of the device, behind the storage area for the web. Because my standards had increased considerably by this point, I was a bit annoyed at how this would look. If I was to keep the case as close to the internal workings as possible, then there would be a sizeable bump at the back of the web shooter, which would look a bit odd and ugly.
But then, just yesterday, I came to a realisation. The motor didn't have to be lying across my wrist. It would work just the same if it was pointing towards my hand. Also, I could easily (and, in fact, it makes things simpler) position the motor above the storage area for the web, rather than behind it, since that's going to be almost completely flat.
With this new design, there will still be a sizeable bump, but it will be in the middle of the web shooter, and will be going along my wrist, rather than across it. This will obviously look much better.
As regards the batteries, they will simply be on the other side of my wrist, thereby making the web shooter not any longer than it would be without the batteries. I have no idea why I didn't think of that when I came up with the original design.
So, here's a diagram of what I consider to be my 'perfected' web shooter design:
The web itself is, too, simple but effective (hopefully). Rather than my original idea of a rod that opens up into an X shape and has sticky pads on the inside, this is simply a string with rectangular blocks spaced along it. The blocks will have sticky pads on the top and underneath. There will be a higher concentration of them on the first few inches of the string, since that's the part that will be used most often (in fact, it probably isn't necessary to have them on the rest of the string, but I'll have them there just in case). When the 'web' hits something, it will bunch up, causing many of the sticky blocks - not just the one on the very tip - to collide with the desired object. Hopefully, that will be enough to stick sufficiently.
Because the motor is connected to the storage area as well as the propelling wheels, that will be spinning as well, presumably eliminating any resistance that would otherwise be created by the string unravelling. It also means that all I have to do to recall the web is reverse the current, making the storage area and propelling wheels spin in the other direction. This recall would - unless I put a resistor on this part of the circuit - be the same speed as the firing speed. This would result in the same effect shown in The Amazing Spider-Man 2, wherein Peter shoots a web at an object, which then gets extremely quickly propelled back to him while the web seems to disappear back into the web shooter.
It may turn out that the sticky blocks will just be pulled right off the object if the string is being recalled at firing speed, so I may well have to use a resistor. But in any case, I'm sure I'll be able to achieve a very decent recall speed, which will undoubtedly be extremely cool.
It's currently Sunday evening, and I kind of rashly accepted a challenge on Facebook to get the web shooter finished by Tuesday. So... I really need to stop procrastinating. However, I have already started! I'm in the process of making two of the three gears (which are a lot harder to make than you might think), and I already have the motor and the propelling wheels from when I was working on the original design last year. So I think, if I really try, I could get this done, or at least mostly done, in time for the ambitious deadline.
I'll let you know.