Location recording Big-brother style

-

A few weeks ago there was a lot of noise on the news about how different providers were handling the location information obtained from smartphone users. I had a look at what was available (user level) on the Android platform. Latitude is a software from Google that allows you several types of location information storage and processing that can be fun, scary or terrifying depending on how you think about it.

Most of the recording is disabled by default (at least this is what we are told) so you do not have to worry. Whether some recording is done on the provider's side or not I do not know. We all know, however, that cellphone carriers do collect location information of all their customer's cellphones.

What Latitude offers you is the possibility of using your smartphone location capabilities (GPS+GSM+wifi based) to provide updates to your Google account so you can:
  1. Check your (cellphone) location anytime on Google Maps.
  2. Check the location of other users that willingly share it with you. You can track your kids, employees, work mates, etc.
  3. Get a report of your total traveled miles in the last month, week, etc. With details of all the different locations you've been to.
  4. Get a detailed usage of your time: hours at home, at work, on the road, etc.
  5. Get recorded data in KML format (XML based).
There is an API to enable the creation of applications that use this information for new purposes too.

I can think in multiple useful uses of this service and of some not so nice ones too.

Next time you're telling your husband you are at a meeting in the office, think it twice :-)

Comments

Post a Comment

Popular posts from this blog

VFD control with Arduino using RS485 link

-
Image
Variable Frequency Drives ( VFD ) allow the control of spindles so speed can accurately be controlled and a detailed acceleration profile for the spindle and reverse rotation can all be handled. In essence a VFD is an three phase inverter for three-phase AC motor. I am using a popular (I mean cheap) Chinese VFD and though the reference manual is not great, I could see there is a built-in RS-485 port. I usually control the start, stop and speed selection using the keyboard on the unit but I thought it will be more useful if I could control everything from the same Arduino is doing our CNC table control. Some cheap RS-485 off eBay and some lines of code later, I can start, stop and change the speed from an Arduino. What a cool thing to have! Some configuration of your VFD are needed before you can use it like that.  You need to set PD163=1 (I am using address 1 in the code). PD=164=1 (for setting serial to 9600bps) and PD165=0 (for using ASCII and 8N1 character format)
Read more

How to get sinusoidal s-curve for a stepper motor

-
Image
After some experimentation, and delving a bit into the math of motion, I realized there can be a significant difference on the motion of a machine by just making small changes. A common and popular approach to smooth one axis of motion is to use a trapezoidal speed pattern, where acceleration and deceleration are uniformly accelerated movements (aka constant acceleration motion) separated by a portion happening at cruising speed. The problem comes with the fact that, while that approach is simple to understand and to code, it does contain sudden changes in the acceleration, that show as spikes on the acceleration derivative, called jerk. These sudden changes in the acceleration translate into undesired vibration in our machines. Most of that can be eliminated by selecting a motion pattern that does not contain sudden changes of acceleration. If we chose a mathematical function for our speed whose second derivative is continuous, then we reduce system vibration quite a lot. One ma
Read more

Stepper motor step signal timing calculation

-
Image
While we use stepper motors in many devices, the timing of the step signals is not always well understood. Most of us can see how a fixed speed is a bad idea unless the speed of motion is really slow, but it is fixed speed what is really to generate with simple code. You just can use the Arduino Blink example to send a fixed frequency of pulses to a stepper motor driver. If too slow, just reduce the delay value. But for most real-life applications variable speed controls will perform better. These systems will speed up the motor to a given maximum speed and it will slow it down to stop at the desired step count. But understanding the math behind this process is sometimes not obvious. Let us start with the simple case of the so-called trapezoidal speed motion profile. Here motion takes place in three phases: acceleration, constant speed (cruising) and deceleration. But the point is how can our code create such a behavior. Stepper motor drivers usually accept two signals to control
Read more