Adept Rocketry

DDC22 Instructions and Data Sheet

DDC22 Dual-Deployment Controller™

Copyright © 1989-2017, All Rights Reserved

DDC22 Dual-Deployment Controller™


The DDC22 is a Deployment Controller™ with two deployment outputs that fire deployment charges, based on altitude. The DDC22 is an altimeter based instrument that uses the same circuitry as the ADEPT22 Altimeter and handles Dual Deployment™, but it does not report maximum altitude after a rocket flight. Because of this, the tedious calibration requirements of the ADEPT22 can be avoided somewhat and allow the DDC22 a substantially lower price. The DDC22 can be used as the primary deployment controlling device if you don't care about measuring altitude (some rocketeers actually don't). But typically it would be used as a redundancy backup device alongside an ADEPT22 (or any other altimeter). The first charge fires when the rocket reaches its maximum altitude (apogee), and the second charge fires when the rocket descends to 1800, 1200, 900, 600, or 300 feet above ground, or 6 seconds after apogee, or at 150 feet below apogee (7 choices, 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. Dual Deployment™ was invented by Adept Rocketry in 1990 when the term was copyrighted and trade marked. The term Dual Deployment™ remains the sole property of Adept Rocketry.

This device is used in rockets that will reach at least 300 feet altitude. Either or both deployment putputs may be used. The DDC22 may be used in any rocket configuration including multistage rockets. Individual DDC22 units may be placed in each stage of interest to handle deployment for that stage. The DDC22 functions to 100,000 feet above sea level.

The DDC22 measures 0.9” wide by 0.6” thick by 2.8” long. It fits inside a tube with a minimum ID of 1.0” (25.4 mm). The device weighs only 0.4 ounce (12 grams). It is designed to be used with a standard 9-volt battery. The DDC22 is a stand-alone device that includes the arming mechanism, and the current drivers for firing deployment charges. A four-pin terminal block is included for connecting to the user supplied external battery, wiring, and On-Off switch.

Once powered up, the DDC22 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. The first deployment output fires at the very moment when the rocket reaches the maximum altitude. The second output fires when the descending altitude reaches either 1800, 1200, 900, 600, or 300 feet above the ground, (or 6 seconds after apogee, or 150 feet below apogee) as preset by the user. Note: the DDC22 cannot be used for, and will not function for, maximum altitudes less than 300 feet.


  • Altitude Capability: to 100,000 feet Above Sea Level (ASL).
  • Liftoff is detected when the altitude quickly increases by 300 feet.
  • Mach Compatible; the DDC22 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.
  • Custom altitude sensor that is immune to light, including direct sunlight.
  • Calibration Accuracy for Deployment Altitudes: +/- 5%, typical.
  • Uses external alkaline 9-volt battery to fire low-current electric match charges. Advanced on-board Voltage Regulator that is totally immune to reverse voltage (battery in backwards).
  • Battery Life: up to 48 hours. Battery Current Consumption of the DDC22 is only 2.7 mA, so the device can run for a week on a 9-volt alkaline battery. However, since the unit's primary purpose is to fire deployment charges, the 48 hour specification should be observed; the battery will remain reasonably fresh for up to 48 hours of operation time. Do not substitute an external battery with a voltage less than 7 volts. A 2-cell Li-Po battery should be sufficient, but complete pre-testing will be necessary.
  • Piezo beeper reports 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.
  • Output #1 fires at maximum altitude; Output #2 fires during descent at 1800, 1200, 900, 600, or 300 feet above ground, or 6 seconds after apogee, or at 150 feet below apogee as selected by the user. The second charge can never fire any sooner than 2 seconds after the first charge fires.
  • Measures 0.9” wide by 0.6” thick by 2.8” long and fits inside a tube with a minimum ID of 1.0” (25.4 mm), It may be mounted to a plate, or flat against a bulkhead in larger diameter tubes.
  • Weighs only 0.4 ounce (12 grams).
  • Accessories Required: one 9-volt alkaline battery, external wiring, and an On-Off switch if one is used. Zero, one, or two Programming Jumpers required to choose the main chute setting - two are included.


NOTE 1: The precision amplifier circuitry and continuity sensing circuitry on the DDC22 may be sensitive to noise and static electricity when being held. Following power up, there is a 10-second silent period to allow time to get your hands off the unit before it starts taking readings. Always handle the device by the edges when testing or installing to avoid touching any of the circuitry. Avoid carpeted floors and other sources of static electricity when handling and testing the device. Never store the device in a clear plastic bag; clear plastic bags are prone to static buildup and discharge. However, pink-colored or smoke-colored antistatic bags are ideal, because they are chemically treated to prevent static buildup. Storage in a small cardboard box, or wrapped in a paper towel inside a clear plastic bag is acceptable. Do not use Velcro to secure the device, as Velcro is a substantial source for unwanted static discharge. The DDC22 is a super precision instrument. Use care to keep the device clean and dry.

NOTE 2: This device must be installed only in a “clean area.” Electronic Instrumentation is not compatible with the fumes and residue created by rocket motors and deployment charges. The DDC22 must be installed in an area that is totally sealed from motors and charges. After passing wires through holes in bulkheads and such, seal them with epoxy or removable putty.


The DDC22 is designed to be powered with an external 9-volt alkaline battery. The same battery also furnishes the current that fires the deployment charges. The negative lead from the battery (usually BLACK) connects to pin 1 of the terminal block on the DDC22.

The positive lead from the battery (usually RED) connects to pin 2 of the terminal block. One side of each deployment charge also connects to pin 2 of the terminal block. Pin two will have three wires connected. It is best to connect the three wire ends together before connecting them to pin 2 of the terminal block. The On-OFF switch (recommended) is connected either in-line in the positive lead from the battery, or in-line in the negative lead if desired.

The other side of the apogee charge connects to pin 3 of the terminal block, and the other side of the main chute charge connects to pin 4.

When the unit is switched on, the unit sounds out a long pulsating beep to indicate proper operation. Then after ten seconds of silence the unit starts beeping once a second to indicate that it is now taking altitude readings and is waiting for liftoff.

If low-current deployment charges are connected, the beeping changes from a single beep to other beeping patterns to indicate continuity of the deployment charges. A single beep indicates proper operation with no deployment charges connected. A double beep indicates continuity of only the first output or first deployment charge, the one that fires at apogee (maximum altitude). A triple beep indicates continuity of only the second output or second deployment charge, the one that fires during descent as selected by the user. Four beeps repeating indicates that both deployment charges have continuity.


When viewing the front of the DDC22 (with the green terminal block to the right), a four-pin square connector is located just below the legend DDC22. When no jumpers are installed on the connector, the default altitude setting is 600 feet above ground. The second deployment charge will fire during descent at 600 feet. When a single shorting jumper is installed horizontally on the lower two pins only, the setting is 300 feet. When a single jumper is installed horizontally on the upper two pins only, the setting is 900 feet. When two jumpers are installed horizontally, on both the lower two pins, and on the upper two pins, the setting is 1200 feet.

Jumpers also may be installed vertically on the four-pin square connector. When a single jumper is installed vertically on the left two pins only (toward the blue capacitor), the setting is 1800 feet above ground. The second deployment charge will fire during descent at 1800 feet.

When a single jumper is installed vertically on the right two pins only (toward the terminal block, the second deployment charge will fire 6 seconds after apogee (6 seconds after the first charge fires).

When two jumpers are installed vertically, on both the left two pins, and on the right two pins, the second deployment charge will fire after apogee during descent at 150 feet below apogee.

With the 6 Seconds After Apogee setting, and the 150 Feet Below Apogee setting it is possible to use the second output as a backup for the first charge. With these settings it is possible to create an apogee deployment sequence that is implemented with two sequential steps. One of the many possibilities for these settings is to click a camera after the rocket's descent has stabilized.

To simulate rocket liftoff it is necessary to pull a vacuum on the altimeter while it is inside a sealed chamber. You need only hold the vacuum for a few seconds, then slowly release. However, the best method is to put the whole device (including wires and flashbulbs or small light bulbs, for testing the outputs) inside a small wide-mouth juice bottle, and pull a vacuum on the bottle (or you may use an Adept VCK2 Vacuum Chamber - see VCK2 Vacuum Chamber and VCK2 Instructions). It is easy to simulate rocket flights to altitudes of several thousand feet. Slowly pull the vacuum, then slowly release the vacuum. As the vacuum (altitude) increases, the DDC22 will BOOP to indicate that 300 feet has been reached (liftoff). Then when the altitude starts its descent (vacuum is being released), a BEEP will indicate that the maximum altitude was reached, and this is when the first output (apogee) fires. When the simulated altitude falls to the user selected altitude above the original ground level, there will be a long BEEP, and this is when the second output fires. The unit then resets to a new start condition. For the present flight, its work is complete.

Warning: never install this device in a rocket without first testing its controlling outputs. Always test before each flight. Also, backup deployment systems and/or instrument redundancy (use of two similar systems in the same rocket) are highly recommended.


The DDC22 may be installed lengthwise in a small-diameter rocket tube. It will fit lengthwise in a 1.0 inch (25.4 mm) ID tube. In larger tubes it may be mounted flat against a plate or bulkhead in any orientation. The mounting holes are .090 inch diameter for #2 hardware. Use #2 screws, standoffs, and hexnuts when mounting the altimeter to a plate or bulkhead. Mounting hole centers are 0.7 inch by 2.0 inches. Do not enlarge the mounting holes, and do not use Velcro.

An altimeter device must be installed in a "sealed" chamber with a vent or vents to the outside. A sealed bulkhead below the altimeter chamber is necessary to avoid the strong vacuum caused by the aft end of a rocket during flight. Any leakage around the motor mount or in other areas at the aft end of the rocket will allow the strong vacuum to be partially felt inside the rocket body. In this case an altimeter could incorrectly indicate and record an altitude that is far higher than reality.

A sealed bulkhead above the altimeter chamber is necessary to avoid any pressure fluctuations that may be created at the nose end of the rocket. If the front of the payload section slip fits to another section such as a nosecone, then the fit must be as free as possible from turbulence.

You cannot ... you cannot put an altimeter device in a rocket along with the parachute and expect to get accurate readings. Sometimes it may seem to work just fine, and sometimes the values may even seem reasonable, but the readings will always be wrong, and active deployment functions may not perform properly. An altimeter must be mounted in its own specially isolated and properly vented payload chamber or electronics bay. If your rocket does not already have one, then you must create one or add one.

A breathing hole or vent (also known as a static port) to the outside of the rocket must be in an area where there are no obstacles above it that can cause turbulent air flow over the vent hole. Do not allow screws, ornamental objects, or anything that protrudes out from the rocket body to be in line with and forward of a vent hole. The vent must be neat and burr free and on an outside surface that is smooth and vertical where airflow is smooth without turbulence.

Some rocketeers use multiple static ports (vent holes) instead of just one. Very strong wind blowing directly on a single static port could affect the altimeter. Multiple ports evenly spaced around the rocket tube may help cancel the effects of strong wind, the pressure effects of a non-stable liftoff, or the pressure effects that occur due to flipping and spinning after deployment. If you wish to use multiple ports, then use three or four. Never use two. Ports must be the same size and evenly spaced in line around the tube.

The general guideline for choosing port size is to use one 1/4 inch diameter vent hole (or equivalent area, if multiple holes are used) per 100 cubic inches of volume in the altimeter chamber. For instance, An eight-inch long four-inch diameter tube has a volume of about 100 cubic inches. Use one 1/4 inch port, or three or four 1/8 inch ports evenly spaced around the tube. An altimeter chamber two inches in diameter and eight inches long (25 cubic inches) needs one 1/8 inch vent hole or three or four 1/16 inch vent holes. Try to keep hole sizes within -50% or +100% of the general guideline. Do not make the holes too small, and especially do not make them too large. In general, the vent holes need never be smaller than 1/32 inch. Also, the vent hole diameter need never be less than the thickness of the body tube.

Adept Rocketry completed the research on static port sizes in 1990. The information provided here has remained the industry standard ever since those early years.

When possible, vent holes should be a minimum of 4 body diameters below the junction of the nosecone with the rocket body. This is necessary with high performance (high speed) rockets. The tremendous pressure on the nosecone leeches down the rocket body as much as three or four body diameters before it dissipates. However, with lower speed rockets, the "minimum of 4 diameters" rule may be reduced to one or two.


Adept Rocketry and Adept Instruments, Inc. warrant to the original purchaser that this product is free of defective parts and workmanship and that it will remain in good working order for a period of 90 days from the date of original purchase. This product will be repaired or replaced within 90 days of purchase if it fails to operate as specified, if returned by the original purchaser and if it has not been damaged or modified, or serviced by anyone other than the manufacturer. Adept Rocketry and Adept Instruments, Inc., their owners, employees, vendors and contractors shall not be liable for any special, incidental, or consequential damages or for loss, damage or expense directly or indirectly arising from customer’s or anyone’s use of or inability to use this device either separately or in combination with other equipment, or for personal injury or loss or destruction of other property, for experiment failure, or for any other cause. This device is sold as an experimental accessory only, and due to the nature of experimental carriers such as rockets, the possibility of failure can never be totally removed. It is up to the user, the experimenter, to use good judgment and safe design practices and to properly pretest the device for its intended performance in the intended vehicle, or reasonable facsimile of same, under controlled conditions to gain reasonable belief that the device and vehicle will perform in a safe manner, and to assure that all reasonable precautions are exercised to prevent injury or damage to anyone or anything. WARNING: Do not use this device unless you completely understand, agree with, and accept all of the above statements and conditions.

The perfect mate for the DDC22 when used in a dual redundancy backup system is the ADEPT22. The ADEPT22 would function as the primary device to measure altitude and to control Dual Deployment™. The DDC22 would function as the redundant backup device to also control Dual Deployment™. The ADEPT22 measures altitude to 25,000 feet with deployment that functions to 100,000 feet.


Programming Jumpers (also known as Shorting Jumpers) are used to connect two connecter pins together in order to turn on the power for some of the Adept devices. Programming Jumpers are also used on some devices to program certain values or functions. They are used on the ADEPT22 to program the value for the Second Output Function, the output that fires the Deployment Charge for the Main Parachute.

Programming Jumpers
Price: $1.39 per pack of 10. Note: two are included with the ADEPT22.

Mounting Hardware

BC1 Premium Battery Clip


VCK2-S Vacuum Chamber, Complete with Bottle and Syringe
Price: $24.95. Use for simulating flights, and for testing Altimeters with or without deployment.

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

Tac'NStik Removable and Reusable Putty
Price: $2.99 per 2 ounce pack.     7/17/17