So, when commuting by bike, there are often obstacles to overcome. Gear to haul, weather to adapt to, health problems to work around, sweat to wick away, repairs to be made, and so on. While many solutions to these problems can be found for sale in local bike shops or the internet, many of us have - at one time or another - come up with innovative DIY solutions to these problems.
As someone with a bit of a DIY streak in me, I am curious to see what others have come up with to solve the common and uncommon hurdles in using a bicycle for transportation, and I am sure there must be others here with that itch to tinker and overcome problems themselves rather than go to the store for a quick (and sometimes costly/wasteful) solution.
So I am inviting you to share the things you have come up with (past and present). If you have pictures, I encourage you to share them (if not, that's okay). Describe what it is you came up with, what it was intended to solve, how well it worked, what didn't work so well about it, and what you might have done differently.
While I do not have a picture, one of my DIY fixes was to my speedometer. Somehow, while I was riding my bike a few years ago I dropped it (I know, it makes about as much sense writing it now as it did when it happened - I think the wheels must have slipped out from under me and I detached myself from it). When that happened, the mount for my speedometer smashed: there was no way to maintain electrical contact between the mount and the speedometer itself, rendering it useless.
I happened to have a couple of 9volt battery clips kicking around my tool box, so I soldered one clip to the speedometer contacts, and the other to the wires coming from the sensor. Then I cut a piece of plastic out of used plastic container (a margarine container or something) , put four holes in it and mounted that to my handlbars with zip-ties. To fasten the speedometer to the plastic mount, I put self-adhering velcro onto the speedometer and my plastic mounting plate.
It worked some of the time. The biggest problem I had was that the soldered points on the speedometer kept coming off (FAR too often). I think if I were to do this again, I would try to disassemble the speedometer, solder my connector somewhere inside the body, and reassemble in such a way as to eliminate any stress on the solder points from tugging on the wire.