- Peak altimeters - These devices are active throughout the flight, but lack the memory to produce a detailed flight profile. The simplest ones just beep or flash the peak altitude; more elaborate models will display other information, such as average speed, time to apogee, acceleration, and so forth. Examples of this class include the Jolly Logic Altimeter One and Two, the Estes Altimeter, and the PerfectFlite Firefly and APRA (The latter is an approved altimeter for this year's TARC competition).
- Recording altimeters - These devices store information throughout the flight, usually at 0.1-0.2 second intervals. This data can be downloaded into a computer or other device, where it can be displayed and/or manipulated. Cheaper ones store data for only one flight, forcing you to download the data almost immediately if you wish to fly it again during a launch; others can store data for many flights, eliminating the need to bring your laptop to the field. Examples are the Jolly Logic Altimeter Three, the Altus Metrum MicroPeak, and the PerfectFlite PNUT (the other TARC approved altimeter for 2015).
|Some of my altimeters. On the left, starting at top: Estes Altimeter, PerfectFlite PNUT,|
Jolly Logic Altimeter Three. On the right: Altus Metrum MicroPeak, PerfectFlite Firefly,
and the Jolly Logic Altimeter Two (pre 2014 version).
Yesterday marked the first time I flew my Altimeter Three. Here are my initial thoughts:
- The Altimeter Three (and the new Altimeter One and Two) is bigger than most of the others - it won't fit in a BT-20 tube, and is very loose in a BT-50. I found that a Centuri ST-8 (0.865" inner diameter) is a good fit, but you may have to make some custom rings to mount this inside an Estes body tube. Jolly Logic sells a snap mount to help attach the altimeter to a sled. Weighing in at 10 grams, the altimeter is also a little bit on the heavy side.
- I like the change to a USB cable for charging the altimeter - a definite improvement over the pre-2014 Jolly Logic devices, which plugged straight into the USB port. They were way too easy to break.
- The Altimeter3 app is currently only available for iOS. However, I just saw a note from John Beans saying that the Android version will be out this coming week, so don't let that stop ya from getting one.
- The Bluetooth interface to the iPhone is a pain - John Beans, the man behind Jolly Logic, is pretty up front about this. Most of it isn't his fault, as Apple implements Bluetooth in a weird way (no big surprise). To help out, he provides a very good Bluetooth setup guide and I was able to get my connection up and going fairly easy. There was some funkiness reconnecting with the altimeter after the flight, but turning Bluetooth off and then back on solved the problem. Still, this was less effort than opening up the rocket and extracting the altimeter to listen to the beeps or watch the flashing LED.
- The smartphone software is very good, and works as advertised. I was very pleased by the simple interface and the amount of data displayed - very nice to have available in the field! The ability to share data with your buds via email or social networks right after the flight is pretty darn nice, and I mucho like the well-formatted Excel spreadsheet that accompanies the email.
Map screen. The app uses your phone's
GPS to locate the launch location, which
is displayed on the map (Click to enlarge).
Sharing screen. You can email your flight
data or share it on social networks from the
field (Click to enlarge).
|Excel spreadsheet accompanying the Jolly Logic Altimeter Three email (Click to enlarge).|