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Archive for the 'magnetic fields' Category

Tricorder: Android Homage To Star Trek

Application Name: Tricorder

Description: Multiple sensor data output, including GPS and compass; solar data.

Publisher’s website: moonblink

Cost: Free

Version/date reviewed: v.5.11  /  10-5-10

Phone/OS: Droid X / Android 2.2

Android Market link (mobile app only)
Android Market link (browser)

While comparing his Droid Incredible with my Droid X a few months ago, a friend commented that the sensor capabilities of the Droids reminded him of the tricorder from the original Star Trek series, a multi-purpose data collector and analyzer. What he didn’t know was that I had a copy of the Android Tricorder app on my unit that makes the connection even more explicit. I can’t say that I find it totally useful – I think there are better apps for many of the functions. But it’s fun to use to show off your Android’s capabilities, and it does have one feature related to GPS accuracy that might surprise you.


Figure 1: A “gravity meter” monitors input from the orientation and accelerometer sensors.


Figure 2: The magnetometer displays information from the unit’s magnetic sensor.


Figure 3: An acoustic meter displays the waveform, spectrum, and noise level for input into the unit’s main microphone (here, me whistling a note).


Figure 4: The geographic section displays location from both network data and GPS satellites; the former is a nice touch, since that data is either not presented by other GPS apps, or is superseded by the GPS data when a fix is acquired. The display at the bottom shows the satellite sky map, and a compass with both true (T) and magnetic (N) directions. Wouldn’t want to use it for navigation, though.


Figure 5: Electromagnetic sensor shows the strength of the local WiFi networks, as well as that of the cellular network. There are lots of apps for the former, but I haven’t seen that many that show cellular network strength this clearly – a good alternative to the cell signal bars on your status bar.


Figure 6: You might think that a solar activity sensor, showing downloaded solar data, might be interesting but not particularly useful. But the plots of proton/electron flux at the bottom can reflect on how accurate your GPS position measurement is. As the sun moves into a more active phase, these fluxes can affect conditions in the Earth’s ionosphere, which in turn can make GPS less accurate. So if you see those plots rising near the end, that would suggest that your GPS position might be less reliably accurate.

Other Issues:

None ; worked fine every time.

Final thoughts:

Perhaps not the best sensor app out there, but too cool in appearance and function not to have, and the solar data is hard to find elsewhere.

Ulysse Gizmo: Android MultiSensor App

Application Name: Ulysse Gizmo

Description: Multiple sensor data output, including GPS and compass.

Publisher’s website: Binary Toys

Cost: Free

Version/date reviewed: v.1.6  /  12-7-10

Phone/OS: Droid X / Android 2.2

Android Market link (mobile app only)
Android Market link (browser)

One thing you’ll immediately notice about Ulysse Gizmo is the “fit and finish”; in terms of visual presentation, it’s one of the more outstanding Android apps of its kind I’ve seen, at least in its default “visual style”. It displays GPS, magnetic and orientation data in four different displays; each one has excellent context-sensitive help.


Figure 1: The magnetic field sensor shows field strength, and the theoretical/actual magnetic strength/direction, along with the local magnetic declination (deviation of magnetic north from true north). More of a science toy than anything else, though I suppose you could use it to detect abnormal magnetic fields.

The icons at the edges represent the other sensor displays, and show actual active data readings. If I tap on the one at lower-left


Figure 2: … a nice bubble level shows up, with pitch/roll/slope orientation data displayed; I wish it also had a readout of the total slope angle along the orientation, but that’s a minor quibble. A quick tap zeroes out the level, while a longer one resets the zero level completely. The bubble level is the default view; if you tip the unit on one of its edges, say a long edge, and do a long press on the level …


Figure 3: It turns into an inclinometer, displaying total angle of rotation, and % slope.


Figure 4: GPS mode displays a sky map of satellite positions, with coordinate data in the box at upper right. Latitude/longitude in DMS is the default option, but you can switch to decimal degrees, UTM or MGRS in the setting section. If you tap on the coordinate box, it will cycle through the coordinate view, a geocoded address readout where available, and …


Figure 5: … a GPS satellite/signal info box. It’s on the small side but packs a lot of readable data into that small space. Here, I’ve changed the visual style from the default to the alternative “Mil-tech” as a comparison to the default style seen above. I personally much prefer the default style, but this alternate might be more readable for some people. There are also day/night color options for both visual styles available from the Menu.


Figure 6: Finally, compass mode. This has been vastly improved from earlier versions, which didn’t include a permanent “Heading” readout. Red needle always points towards true north, blue towards magnetic north; the numbers at top represent the counter-clockwise deviation from north, not the actual heading, which is a bit confusing. But the true heading (and orientation) are always visible in the center. Tapping once on the compass sets the current heading as a direction bearing, aiding in navigating in a constant direction; a long press resets that bearing.

The original version of this review before publication noted that there was a setting for waypoints, but it hadn’t been implemented. Just a few hours before scheduled publication, that changed …

Figure 7: From the menu on the compass page, choose the “Waypoint” option, and you’ll get a local map. A long press on the map at any location will place a waypoint there, and you’ll see info about the waypoint (bearing, distance, coordinates) at the top

Figure 8: Tap and drag on a waypoint lets you relocate it, and brings up a magnified view of the area under the waypoint – a nice touch, since your finger will block that part of the map as you’re moving the waypoint.

Figure 9: Returning to the compass page, the info box now includes data on the waypoint. There’s also now a small white circle on the edge of the compass ring, which shows the bearing direction towards that waypoint. You can remove the waypoint from an option in the waypoint menu, and also “link the bearing” to the waypoint; that will make the bearing display inside the compass correspond to the bearing to the waypoint.

Other Issues:

None – worked fine.

Final thoughts:

Ulysse Gizmo is a  visually-appealing app that shows off the Android sensors nicely. I prefer other apps for GPS status and coordinate data, and I don’t really see any need on my part for a magnetic field sensor. But the orientation app, especially the inclinometer option, is really nice, and the compass’s ability to let you set a bearing is useful. The author was very responsive to suggestions and bugs, and is working on adding additional features. Recommended.