Adept Rocketry ALTS25

Maximum Altitude Altimeter with Dual Deployment™

           Prints Actual Size at 96 pixels per inch.

ALTS25, Price: $99.00 - Includes CAB6L-24 Interconnect Cable and GP-23A Battery.

ALTS25-60K, Price: $134.00 - Includes CAB6L-24 Interconnect Cable and GP-23A Battery.

The ALTS25 Altimeter with Dual Deployment™ is a maximum altitude altimeter. It measures and reports the maximum above-ground altitude value of a rocket's flight. The ALTS25 also has two altitude controlled deployment switches for firing deployment charges, based on altitude. The first charge fires when the rocket reaches its maximum altitude (apogee), and the second charge fires when the rocket descends to 1,800, 1,200, 900, 600 or 300 feet above ground, or two seconds after apogee, or at 150 feet below apogee (user selectable). One common usage is to deploy a main parachute at apogee by using only the first output. However, the most typical usage is to deploy a drogue chute or streamer first, then to deploy a main parachute when the rocket descends to a user selected altitude above ground (Dual Deployment™), in order to avoid significant drifting due to wind.

This device is used in rockets that will reach at least 300 feet altitude. Either or both deployment switches may be used, or the device may be used as a maximum altitude altimeter only. The ALTS25 may be used in any rocket configuration including multistage rockets, in which case maximum altitude information about a particular stage can be obtained by placing the device in the particular stage of interest. Or individual ALTS25 units (or other altimeter devices) may be placed in each stage of interest to report maximum altitudes obtained by each stage, and/or to handle deployment for each stage.

The ALTS25 precisely captures the highest altitude obtained during a flight to a maximum of 25,000 feet above sea level (by special order, the ALTS25-60K is calibrated to altitudes up to 60,000 feet). The maximum value obtained above the local ground-zero altitude is precisely measured and reported in one-foot increments (one-foot resolution).

The ALTS25 measures 1.4” wide by .6” thick by 3” long. It fits inside a tube with a minimum ID of 1.5” (38 mm). It will also fit on either side of a center divider inside a 54 mm ID bay 3” long. The device weighs only 1 ounce, including the battery. It uses a 12-volt alkaline lighter battery with a battery life up to 6 hours, so you need not be concerned about how long your rocket sits on the launchpad after the unit is powered up. The ALTS25 is a totally stand-alone device including the battery holder, arming mechanism, and current source for firing deployment charges. Nothing more is required except for the wires (interconnect cable) that connect to the On-Off switch and to the deployment charges.

The altimeter uses a custom absolute pressure device to precisely measure altitude values up to 25,000 (or 60,000) feet in one-foot increments. It uses a 17-bit logarithmic analog-to-digital converter to precisely (one-foot resolution) measure the nonlinear pressure versus altitude relationship over this large altitude range. Once powered up, the ALTS25 reports that neither, or one or both deployment charges has continuity. It also constantly measures the ground-level altitude and waits for a quick 300-foot change upward. It then captures the maximum altitude obtained above ground zero. The first deployment switch fires at the very moment when the rocket reaches the maximum altitude. The second switch fires when the descending altitude reaches either 1,800, 1,200, 900, 600 or 300 feet above the ground, (or two seconds after apogee, or 150 feet below apogee) as preset by the user. The ALTS25 uses the copyrighted and patented and trade marked technique of beeping out (blinking on some models) a value to report the maximum altitude value. The beeps can be heard even when the unit is still inside the rocket. The rocketeer knows the maximum altitude as soon as he/she picks it up, or just gets close to it. Note: the ALTS25 cannot be used for, and will not function for, maximum altitudes less than 300 feet.


  • Altitude Capability: to 25,000 feet Above Ground Level (AGL), to limit of 25,000 feet Above Sea Level (ASL) for the standard version (60,000 feet by special order). Note: the latest version of the ALTS25 actually measures and reports altitudes to 100,000 feet ASL. However, above the normal specified ranges, accuracy is not guaranteed. Apogee detection functions to at least 60,000 feet for the Standard ALTS25, and to 100,000 feet for the extended ALTS25-60K version.
  • Nonvolatile Memory: remembers and reports the altitude of the most recent flight, no matter how long the device has been powered down.
  • Lowest Maximum Altitude Readable: 300 feet above ground. Liftoff is detected when the altitude quickly increases by 300 feet.
  • Mach Compatible; the ALTS25 uses Adept's proprietary Real Time Dynamic Lockout™ system that tracks speed in real time to ignore pressure glitches that occur when transitioning through the sound barrier, both in and out. This system is possible due to the extreme precision of one-foot resolution measurements.
  • Resolution of Measurement: one foot; uses a logarithmic 17-bit A-to-D converter.
  • Calibration Accuracy Over Full Range:  +/- 1%, typical.
  • Uses 12-volt lighter battery and has large integral capacitor to fire flashbulb or low-current electric match charges. Battery Life: up to 6 hours.
  • Piezo beeper reports altitude and operational status including the continuity of the deployment devices. One repeating beep if neither device has continuity, two beeps repeating if only device #1 has continuity, three beeps if only device #2 has continuity, and four beeps if both devices have continuity. The beeper uses a push-pull driver for increased volume level, loud enough to serve as a location beacon for a lost rocket.
  • Switch #1 fires at maximum altitude; Switch #2 fires during descent at 1,800, 1,200, 900, 600 or 300 feet above ground, or two seconds after apogee, or at 150 feet below apogee as selected by the user, or 2 seconds after Switch #1, whichever occurs last.
  • Measures 1.4” wide by .6” thick by 3” long and fits inside a tube with a minimum ID of 1.5” (38 mm), or on either side of a center plate inside a 54 mm ID tube. Also, it may be mounted flat against a bulkhead in larger diameter tubes.
  • Weighs only 1 ounce with battery installed.
  • Accessories Required: one 12-volt alkaline lighter battery, and one cable (Adept CAB6L-xx series) to connect an On-Off switch and deployment charges.


Additional CAB6L-24 Interconnect Cable
Price: $7.50 - 24 inches long. Connects ALTS25 to On-Off Switch and to Deployment Charges.
CAB6L-12 Interconnect Cable
Price: $5.99 - 12 inches long.
CAB6L-36 Interconnect Cable
Price: $8.79 - 36 inches long.

Additional GP-23A Alkaline Lighter Battery; Price: $2.25.

GP-23A50 Alkaline Lighter Batteries (box of 50 at 50% Discount); Price: $56.25.

Shorting Jumpers are used to connect two connecter pins together in order to turn on the power for some of the Adept devices. Shorting Jumpers are also used on some devices to program certain values or functions. They are used on the ALTS25 to program the value for the Second Output Function, the output that fires the Deployment Charge for the Main Parachute.

Shorting Jumpers
Price: $1.39 per pack of 10

VCK2 Vacuum Chamber, Complete with Bottle
Price: $16.79. Use for simulating flights, and for testing Altimeters with or without deployment.

Electronic Instrumentation is not compatible with the fumes and residue created by rocket motors and deployment charges. Seal holes and gaps in bulkheads and such with epoxy or removable putty.

Tac'N Stik Removable and Reusable Putty
Price: $1.99 per 2 ounce pack.

The perfect mate for the ALTS25 when used in a dual redundancy backup system is the DDCS25. The ALTS25 would function as the primary device to measure altitude and to control Dual Deployment™. The DDCS25 would function as the redundant backup device to also control Dual Deployment™. The DDCS25 functions to 60,000 feet. The extended DDCS25-100K version functions to 100,000 feet.

DDCS25 Dual Deployment Controller™
Price: $79.00
- Includes CAB6L-24 Interconnect Cable and GP-23A Battery.

DDCS25-100K Dual Deployment Controller™
Price: $99.00
- Includes CAB6L-24 Interconnect Cable and GP-23A Battery.

Copyright © 1989-2011, All Rights Reserved      9/12/11