So this guy Ted Benson [who named his kid Everest, great move] just posted about how easy it is to hack Amazon Dash buttons, those ridiculous little gadgets Amazon wants you to put around your life so you can reorder stuff with one-product-one-click, to automatically track kid data. You just write these python scripts and capture these MAC addresses and automatically post the data to a Google spreadsheet using the app his startup just launched last week and--aha. Always be evangelizing.
Basically the Dashes send out a single message over wifi with a single touch; Amazon intends for that to be a product order, but you can reprogram them to log, say, diaper changes or feedings or naptimes. It wasn't clear from the writeup, so it took me a little while to confirm that Benson's solution requires a separate button for each type of data. You could have one diaper change button, but you'd need two buttons to track pee and poo. For feeding, you could have one near the fridge, or near the bed or the rocker, but you'd need it somewhere. Unless you're going to wear it like a Fitbit or something.
Weighted Companion Cube rendering by saphirenishi at deviantart
Couldn't you put all the Dashes into one device? Just put a different button on each side of a gently glowing, wifi-enabled cube, and it could be a companion for the kid. Why has no one thought of this already? Get me Kickstarter on the horn!