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Altimeter Two Generation Two


  • Model: JL ALT2
  • Manufactured by: Jolly Logic

Building on top of the features of the popular second-generation Altimeter One, the Altimeter Two is a rechargeable digital altimeter (for model rockets only) that analyzes flight altitude, acceleration, top speed, flight duration and 6 other important flight statistics.

The AltimeterTwo retains the rugged design, easily-readable bitmap-display LCD, small size, and rechargeability of the AltimeterOne. With the addition of a 3-axis accelerometer and a 4X speed increase in processing speed, it can provide a full suite of important flight statistics that can help you analyze and improve your rocket’s performance.

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  • 3-axis, 24g accelerometer can detect launch, acceleration, speed, ejection, and landing
  • Accurate 19-bit barometric pressure sensor sensitive to altitude changes of less than one foot
  • Daylight-readable LCD display clearly displays all flight statistics−no computer needed
  • Rechargeable Lithium Polymer battery lasts for hundreds of launches, no batteries to buy, connector makes it easily replacable
  • Recharges in less than 2 hours from any standard USB port with included cable.
  • Samples pressure over 25 times/second, and acceleration over 250 times/second
  • Automatically powers down to conserve power
  • Handy enlaarged tether point allows secure attachment
  • Rugged fiberglass and ABS construction to survive crashes
  • Approved for use in official contests
  • Displays results in either English or metric units

Size and Weight

Size 0.57″ x 0.71″ x 1.93″ 1214.5mm x 168mm x 49mm
Weight 0.36 ounces 9.9 grams

Range and Precision

Max Altitude (above sea level) 29,500 feet 9000 meters
Max Acceleration Minimum of 23 gees
Maximum of 40 gees (careful mounting)
Minimum of 23 gees
Maximum of 40 gees (careful mounting)
Altitude Precision Nearest foot below 10,000
Nearest 10 feet above 10,000 feet
Nearest meter
Acceleration Precision Measured to nearest 0.0007 gee
Displayed to nearest 0.1 gee
Measured to nearest 0.0007 gee
Displayed to nearest 0.1 gee
Speed Precision Nearest MPH Nearest KPH
Timing Precision Shown to nearest 0.1 second Shown to nearest 0.1 second


Altimeter Two Generation Two User Guide

Changes to the Altimeter Two Generation Two

  1. More advanced display
    1. You can see from the images that screens are more clearly labeled.
    2. When you hold down the button a menu appears which now smoothly scrolls. When you select a menu item, it flashes to confirm your selection. For instance, you select “Launch” instead of the cryptic “0000” to prepare for launch.
    3. Battery level is now indicated as a percentage, such as “Battery Level 75%.”
  2. Stores last 100 flights
    1. If you choose History from the menu, the last 100 flights (from most recent to oldest) are shown one after another.
    2. Flights are sequentially numbered.
    3. You can also choose Erase to clear all flights.
  3. New battery
    1. In the new design, the battery is much larger and will retain charge for months. When you pull this generation out of your range box, you can be more sure that it will still have power. The old design did not have great shelf life.
    2. The new battery has a connector, so it can be replaced. It’s a custom battery, so we’ll offer replacement units.
  4. Slightly larger
    1. The new design has a larger, sturdier slot that’s easier to attach with a line. Hooks and rings are no longer needed or included.
    2. The slight size increase may mean it may not fit in some very small spaces that the old generation could. You should plan to check this out.
    3. There is a new accessory, the Snap Mount. If there’s a place to mount the Snap Mount, it securely holds the altimeter so you can quickly snap it in and out.
  5. USB Port rather than a built-in plug to recharge (cable included)

The more universal USB Micro-B port is compatible with lots of chargers already out there (it’s the most common on small devices). The included cable will fit in EVERY (not just most) normal USB ports on laptops, etc. Also, it only fits one way, eliminating confusion.

  1. More parts are replaceable

The battery and display have connectors. Like the outside case, it’s easy to snap replacements in.

Changes Specific to AltimeterTwo

  1. All data is automatically shown (no longer need to select a menu item to see it)
  2. Some units are changed (e.g. instead of KPH, metric uses m/s)
  3. Some figures are shown to two decimal places, such as Thrust Time (e.g. “1.99 sec”)
  4. Instead of flashing, the display uses a “>” symbol to note acceleration overload when actual speed, acceleration may be higher than shown (e.g. “>723 mph”)
  5. Pressure is sampled 25x per second, acceleration 250x (slight speed up)

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