Altimeter Two by Jolly Logic

Altimeter Two by Jolly Logic
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Price: $79.00
Product ID : jollytwo
Manufacturer: Jolly Logic
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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 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.

(Click the image for a larger view.)


  • » 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
  • » Recharges in less than 2 hours from any standard USB port, no cable necessary!
  • » Samples pressure over 30 times/second, and acceleration over 244 times/second
  • » Power button turns device ON/OFF and RESETs the display between flights
  • » Automatically powers down to conserve power
  • » Handy tether point allows secure attachment, or independent streamer recovery
  • » Rugged fiberglass and ABS construction to survive crashes

Size and Weight

Size 0.47″ x 0.64″ x 1.93″ 12mm x 16mm x 49mm
Weight 0.24 ounces 6.7 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


Simple Instructions

Just want the basics? Here’s how to use the AltimeterTwo, in as brief a form as possible:

1. Press and release the button quickly to turn the AltimeterTwo on or off.

2. Clear and reset for the next flight by holding the button down and releasing it when “0000″ appears.

3. View detailed information from the last flight by holding the button down and releasing it when “dAtA” appears.

4. Recharge by plugging it into a USB port on a computer. Make sure a red light appears when you plug it in; take it out after the green light appears.

AltimeterTwo User Guide

AltimeterTwo User Guide

Step-by-Step Tour

Here’s a detailed walk through of how to operate the AltimeterTwo.

Turning It On and Off

Press the button and release it quickly to turn the AltimeterTwo on and off. Even though the button is small, you don’t have to use a sharp object to press it. Just press it with the pad of your finger, and it will “click.”

Accessing the Menu

If you press the button and continue to hold it down, you will be presented with a series of choices on the screen, one after another, which you can select by letting go of the button.

Resetting for the Next Flight

If you hold down the button and let go when you see “0000″, you will clear the results of the last flight and the AltimeterTwo will be ready for the next flight. On the screen, you will now see an animated “0″ like this:

After the Flight

The AltimeterTwo will automatically display the apogee and top speed of each flight. The display alternates between showing each.

ŒŽ . . .

Detailed Flight Data

To see the additional flight statistics from the most recent flight, hold down the button and let go when you see . The flight statistics are presented one after another. You can interrupt at any time by pressing the button to exit the detailed display.

Here are the screens you will see when you select the “dAtA” option:

What It Means
Burn Time
. . . . . .
The length of time (in seconds) that the engine produces thrust
Peak Acceleration
. . . . . .
The maximum rocket acceleration during engine burn (in Gs)
Average Acceleration
. . . . . .
The average acceleration from ignition until motor burnout (in Gs)
Coast to Apogee Time
. . . . . .
The delay between motor burnout and the moment of highest flight (in seconds)
Apogee to Ejection Time
. . . . . .
The time between the peak of flight and parachute ejection; can be negative if ejection is on the way up (in seconds)
Ejection Altitude
. . . . . .
The altititude at which the parachute is ejected (in feet or meters)
Descent Rate
. . . . . .
The average vertical speed from ejection to landing (in MPH or KPH)
. . . . . .
Time of flight from ignition to landing (in seconds)

Time of flight from ignition to landing (in seconds)

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Product Reviews

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Reviewed by dyaugo
06/27/2012 - 06:46:24 PM
Great product! A must have!
I had a chance to try out my new Jolly Logic Altimeter 2 last weekend. I headed out to the dry lake bed near my house and put it through it's paces. Right off the bat I found it very easy to use and the illustrations and instruction are clear and concise.

It requires that you drill 3 holes equally spaced around the rocket's diameter. I just make a tick mark with a straight edge inline with the fins. On smaller rockets say BT-70 and below I would use 1/16" hole anything above that up to 4" stay with 1/8" the holes are so that the altimeter can sense the atmospheric pressure and record the peak altitude. It covers this in the instructions.

Before you decide on attaching it to your rocket you may want to launch your rocket a few times without it, just to see where it lands and how far it drift. I did only because I wanted to make sure I got it back especially if you plan on sending it up in a rocket that hits a mile plus!

The Altimeter 2 offers great performance. I flew it over a dozen times on different rockets and never had any issues. For added protection I think you can fabricate or buy a case/cozy for it, but I flew mine "as is"

The only con that I can see is the snap swivel that comes with it. This is just my personal preference, but I would like to see something a little reliable perhaps. I switched mine out and decided to use a key ring for added strength.

This is a really device to have in your range box and a lot fun to see how high some rockets will fly. Worth every dollar!

Reviewed by dyaugo
06/27/2012 - 03:18:55 PM
Great product I highly recommend it
I actually received mine as a gift and just now had a chance to use it. This is a really cool altimeter and really easy to use. The instructions and illustrations are clear and concise. I had no issues with using mine. It worked perfectly every time.

It mentioned in the instructions to drill 3 holes equally spaced around the diameter of the rocket so that the altimeter can sense the atmospheric pressure and record the peak altitude. The holes can be very small. I would recommend 1/16-inch diameter on your smaller rockets below BT-80 and anything above I would go with a 1/8" hole. Just make sure that they are just below the shoulder on the nose cone so that they aren't block by the nose cone when it is inserted into the rocket.

I also launch the rocket a couple times without the Altimeter to get an idea of how high and how far the rocket will drift. I just want to make sure I get it back.

I can't think of any CON's except that maybe the snap swivel is a little to flimsy for my taste so I just upgraded it and used a thick key ring and I slipped it through a quick link. If I bring my laptop I designed an Excel spreed sheet to record all the flight information.

I also fly it "as is" but if you wanted you can design a Fabric/Rubber cozy for added protection (optional) you can.

All in all it's a great product and I would definitely recommend it. It's fun to see how high your rocket goes.

Reviewed by dyaugo
06/27/2012 - 10:28:33 AM
Great Product! Great Price!!
Just recently I had the opportunity to use my Jolly Logic Altimeter 2. This device is really cool and easy to use. The instructions are very clear and concise. In order for it to work you must drill 3 holes into your rocket equally spaced around the diameter and just below the nose cone shoulder so air can pass through. I make mine 1/16" on the smaller and anything above a BT-80 I drill 1/8" holes. Make sure the holes are neatly and cleanly drilled. Another step is I like to launch the rocket a couple times before installing the altimeter so I can get an idea of how high it's going and how far it will drift. This insures me that I will be able to retrieve it. When you have a $70 altimeter on board you want to make sure you get it back. I wasn't really impressed with the clip it came with for attaching it to the nose cone or thereabouts so I used a regular and thicker key chain ring. Some rocket guys out there use or fashion a case to protect it, which is fine, but I fly it "as is" and have not had any issues with it. You can record the flight information on a paper chart or better yet use an Excel spreadsheet with the information. This way you can store the data on your laptop computer. A very cool device/tool to add to your field box.

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