Last week I posted about Mobile Applications that Monitor Transportation activity like ecorio, Carbon Diem and UbiGreen. greenMeter is an iPhone application that computes fuel usage and driving characteristics based on the iPhone’s built-in accelerometer (the New York Times has a nice write-up on other iPhone car applications).
From the greenMeter website:
greenMeter is an app for the iPhone and iPod Touch that can compute your vehicle’s power and fuel usage characteristics, and help evaluate your driving style to increase efficiency, reduce fuel consumption and cost, and lower your environmental impact. Based on the gMeter vehicle performance app, greenMeter uses the device’s internal accelerometer to measure forward acceleration and compute engine power, fuel economy, fuel cost, carbon footprint, and oil (barrels) consumption.
One has to wonder how accurate the iPhone’s accelerometer is in order to correctly track fuel efficiency. The New York Times explains:
Getting accurate results depends largely on the accuracy of the variables you tap in before using the program. Some are easy, like the per-gallon cost of fuel (diesel or gas), weather conditions and the vehicle’s total weight, which means factoring in your own as well as that of any passengers. (The car’s weight is usually listed in the owner’s manual).
Other required variables are not so easy to produce. Drag coefficient? Rolling resistance? Those numbers are rarely on the tip of the tongue of any but the most passionate driving enthusiasts.
One major hang-up with using such an application on the iPhone is that it must be explicitly started every time you begin a trip. This is a limitation of the iPhone itself–processes aren’t allowed to execute in the background. Ideally, an application such as this could run in the background (as a very low priority process) until “vehicle travel” was detected. Otherwise, how many of us would remember (or would be diligent enough) to start this application every time we get in our cars? For UbiGreen 2.0, We are currently working on using the iPhone/Android’s internal accelerometer to automatically disambiguate transportation modes (e.g., bus vs. train) as well as to see if we can accurately detect the car door that a person enters/exits.
Detecting acceleration speeds to determine how someone is travelling? ….I see a big market and breakthrough for this kind of feature ..keep it up!
Interesting idea and a very similar proposed app to the one that is available free on the store, albeit with the exact opposite intention. PocketDyno uses the built in accelerometer to calculate 0-60 times, max acceleration, horesepower estimates 1/4 mile times, etc. Simple process to make sure your results are as poor as possible!