The point of pullups is to improve upper body strength and muscularity. Once one is able to do 10-15 pullups in one set with bodyweight the stress of this unweighted movement is insufficient to cause much further adaptation.
At this point the trainee should start doing pullups with added weight and/or do pullups on ropes, a fat bar or a vertical pipe.
So, instead of actually making real progress in improving his grip, upper body and back strength, the OP has managed to spend a lot of money quantifying something almost worthless. That money and time could have been productively invested in buying some sand, putting it in heavy garbage bags and then loading a backpack to add weight to his pullups.
Note: For a cheap(possibly free) pullup training tool simply get a regular claw hammer, use the claw on top of the doorjam(or tree limb) and grab the handle with both hands and do pullups. Chalking your hands will almost certainly be required otherwise they will slip off.
Recently my consulting firm was tasked with detecting the calisthenics exercises (push-ups, sit-ups, and pull-ups) involved in the Navy SEAL physical screening test. After much research, we were able to use the accelerometer and gyroscope on the iPhone in tandem to achieve this. I was surprised at the level of success we were able to attain. You inspire me to write up a bit about how we were able to make this work.
If you are interested in this app, feel free to check it out here: http://itunes.apple.com/app/sealready/id520161454
"This is a paradigm shift in fitness apps utilizing the best features in mobile technology moving one step closer to wearable computing to determine the physical conditioning level of athletes who want to test their mettle to see if they have what it takes physically to just get their foot in the door as a potential candidate to become a Navy SEAL, EOD, Diver, Special Warfare Combatant Crewmember, or AIR Rescue Swimmer? SEALReady guides you through a simulated physical screening test and lets you know how you stack up. It’s an intense mini triathlon without the bike but throws in a 500 yard swim using only a side, combat swimmer, or breast stroke, a minimum number of calisthenics, but you want more to score, and a timed GPS run."
Something like this might be clearer - it outlines what the app is actually for in the first couple of lines, and misses out all the empty buzzwords (paradigm shift? really?):
"Do you have what it takes to become a potential Navy SEAL, EOD, Diver, Special Warfare Combatant Crewmember, or AIR Rescue Swimmer? Check your physical conditioning level and test your mettle with SEALReady. SEALReady guides you through a simulated physical screening test - a 500 yard swim, calisthenics, and a timed run - and lets you know how you stack up."
A good copywriter could probably get that even snappier.
Oh, also, having your customer review be made from the same account name as your HN account doesn't make it look very convincing ;)
Also, transparent information gathering could be useful for later investigations. For example, you might eat normally for two months and then analyze which calorie sources you'd be most willing to sacrifice.
How do you handle the accelerometer differently for the different exercises (swim, push-up, curl-up, pull-up, run)? And how are you able to support swimming?
How practical is the pull-up bar though? All I can think of is that Far Side cartoon (you know the one with the guy on the floor after hitting his head doing pullups), which Gary Larson said is his only cartoon based on personal experience.
I am trying to decide on the best approach on getting some sort of pull-up bar inside an apartment with ceilings that I can reach on my tiptoes.
Provided the Phidgets work well with Linux, which is not clear to me ATM.
To take this to the next level I would want geofenced app integration so that if I started to slack off, and I was home, I would get a reminder to go do some pullups.
