Mobile applications today with accelerometer sensor can work as a Pedometer or Step Counter for counting the number of steps you take while walking, running or step aerobics. In this blog I will discuss how it works and review of couple of apps on Android and Iphone.
Benefits of Pedometer or Pedometer Apps:Using a Pedometer helps in keeping track of the steps you take while doing aerobics, running, walking, steps exercise.While starting any fitness activity, You set some goals and would like to monitor it. E.g. If you have to prepare for a marathon which is 2 months away, You make a schedule of running every morning. Now you run everyday and follow the same or different path. Sometimes you feel very tired and reduce the distance or sometimes you increase the distance, But you do not have track of whether your stamina or performance is increasing or not. If you do your activity using the Pedometer, It will capture the details like distance covered each day, Steps taken and duration. You can review your performance after days and weeks to check whether it is improving or not.
How accurate is the Count: It is close to the actual count but need to be started and stopped at right time.e.g. If you start the app before starting your jogging and end it after you complete it, then the count will be near to the actual count. But if you start the app, and talk on phone or play some game on it, then chances are that this activity will increase the step count.One obvious question is that can these applications record all the steps taken by a person with the app on the phone in a day? The answer is, It can provide a rough idea of it but not accurate numbers. Some of the tasks like picking up the phone ,putting it down, sliding it , holding it for clicking picture etc. may also increase the step count.
Where you need to keep your phone: It does not matter where you keep it and you should keep it at a place where you are comfortable for free body movement. You can keep it in pocket,in jacket, hold it in hand or keep it in purse. As long as it is directly or indirectly attached to your body during motion it will give the number of steps. Also it does not matter whether you keep your phone straight or upside down.
Does it use GPS: These applications work without GPS also, So we can assume that it does not need GPS for step counting. But if the application has other features like showing the map of the track you followed while jogging, then GPS will be required.
Affect on Battery: Pedometer apps do consume battery a lot as it continuously use the Phone sensors.Newer versions of Apps consume lesser battery.Google claims that Android 4.4 accelerometer sensor works on low power mode and consume less battery.
How it works?: These applications work with the phones which have the Accelerometer sensor built in it. While running, this application will monitor the change in accelerometer and based on it will conclude if the step is taken. It can provide the information about the angle at which you are holding the device, direction , speed at which it is moved and the gravity. Accelerometer provides the values whenever they are changed along with the Time at which the event occurred. Application stores these values in the database and look for a pattern.
An accelerometer will provide three values x-axis value, y-axis value and z-axis value. As the person starts taking the first step, x-axis value will increase at a rate depending upon the force at which the person starts to move, y-axis which will tell the relative change in the height of the device along with the force will show an increase in value as while taking the step person will rise from the ground and then it will decrease till the step touches the ground. Based on this kind of pattern match, Step event is detected. Same kind of concept is used in wave to answer feature provided in phones.
Android Kit Kat 4.4 Step Detector and Step Counter(Developers Only Information): Android has introduced the low power step detector feature in the platform itself. Developers can use this feature and don’t have to write own code/algorithm for step detection. Apart from this a Step Counter is also introduced by the Android in Kit-Kat which will maintain the count of steps taken after the sensor is registered for listening of step events. Here are some key steps for implementation for using the Step detector
1:Extend the activity to implement SensorEventListener(). 2:Extend the activity to implement SensorEventListener(). 3:Get the Sensor Manager using getSystemService() 4:Check for the availability of Sensor and get the sensor using getDefaultSensor() functionality of Sensor Manager specifying the Sensor type 5: Register for the listener using the registerListener() functionality of Sensor Manager and providing the frequency at which you need the event notification. 6:Implement the logic for displaying or using the Step event in onSensorChanged() function called by the system.Check for the time-stamp for duplicate events.
Review of Pedometer Apps: Here is the review of popular apps available for Smartphone:-
- Runtastic Pedometer: This is probably the best app available and works quite well. It captures relatively accurate step counts,have a great user interface and captures the summary of your activities well.
- Noom Walk Pedometer: The only advantage of this app is that it use less battery as compared to other apps. But it does not have the lot of rich features like measuring distance, Speed and duration and detailed summary for checking your performance. As per the App developer, It can be turned on for a complete day and will affect only 2% of battery. I have not used it for whole day, But it is good for those who want to keep the pedometer on whole day without much impact on the battery. Accuracy of this app is not as good as Runtastic Pedometer.
- Pedometer 2.0:This app has good interface like Runtastic Pedometer. It does capture distance and time.Pedometer 2.0 is quite sensitive and was increasing the Step count even with a slight movement of phone after the activity was finished and it also asked to specify whether the activity is walking or running manually whereas Runtastic Pedometer did not ask for the same.
How to Check Sensitivity or Accuracy of Pedometer Apps: One simple test is to open the app on the phone, start the session using the button on the app. Start tapping on the app using your finger and you would see number of steps and distance will increase rapidly. The app which shows lesser number of steps when tapping is less sensitive. I did the same test on the above three apps and the winner was Runtastic Pedometer followed by Noom Walk and Pedometer 2.0
Don’t want to carry phone for counting steps: If you don’t feel comfortable carrying phone because of its weight,size or not fitting comfortably in your pockets, Try the Pedometer devices which are available in the market. These devices are small and lightweight. They provide good accuracy level and are quite handy. Some of them come with fashionable bracelet style.