Adept Rocketry

DDCS25 Instructions and Data Sheet

DDCS25 Dual-Deployment Controller™      Two Versions: 

DDCS25 functions to 60,000 ft.

DDCS25-100K functions to 100,000 ft.

Copyright © 1989-2013, All Rights Reserved

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.

DESCRIPTION

The DDCS25 Dual-Deployment Controller™ is based on the ALTS25 Maximum Altitude Altimeter with Dual Deployment™. It is the same as the ALTS25 in all its functions except that it does not report altitude. It is less precisely calibrated than the ALTS25 and is therefore lower in price. One of its primary uses is as a redundant backup for the ALTS25 (they both fly in the same vehicle). Or the DDCS25 may be used as a primary device to control Dual Deployment™ in a flight when the actual altitude attained is not important. The DDCS25 has two altitude controlled deployment outputs that are typically used to fire 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 1800, 1200, 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. 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 switches may be used. The DDCS25 may be used in any rocket configuration including multistage rockets, in which case the deployment control for a particular stage can be handled by placing the device in the particular stage of interest. Or individual DDCS25 units (or other altimeter devices) may be placed in each stage of interest to handle deployment for each stage. The DDCS25 functions to a maximum of 60,000 feet above sea level. The DDCS25-100K is an extended version that functions to 100,000 feet.

The DDCS25 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 DDCS25 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 device uses a custom absolute pressure device to precisely measure altitude values up to 100,000 feet in one-foot increments. It uses a 18-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 DDCS25 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 switch fires at the very moment when the rocket reaches the maximum altitude. The second switch fires when the descending altitude reaches either 1800, 1200, 900, 600, or 300 feet above the ground, (or two seconds after apogee, or 150 feet below apogee) as preset by the user. Note: the DDCS25 cannot be used for, and will not function for, maximum altitudes less than 300 feet.

SPECIFICATIONS

  • Altitude Capability: to 60,000 feet Above Sea Level (ASL). The DDCS25-100K functions to 100,000 feet.
  • Lowest Maximum Altitude Required: 300 feet above ground. Liftoff is detected when the altitude quickly increases by 300 feet.
  • Mach Compatible; the DDCS25 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, using a logarithmic 18-bit A-to-D converter.
  • Accuracy Over Full Range: +/- 5%, typical. Altitude is not reported.
  • 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 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.
  • Switch #1 fires when the altitude reaches maximum; Switch #2 fires during descent at 1800, 1200, 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.

TESTING AND USING THE DDCS25

NOTE 1: The precision amplifier circuitry and continuity sensing circuitry on the DDCS25 may be sensitive to noise and static when being held. A 10-second silent time following power up gives 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 DDCS25 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 DDCS25 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.

Install a 12-volt alkaline lighter battery (GP-23A, Eveready Energizer No. A23, Radio Shack 23-144, etc.) in the battery holder. The spring end of the battery holder connects to the negative end of the battery. Remove the battery when not in use to avoid prolonged stress on the battery holder and possible long-term disfigurement of the battery holder.

Connect an Adept CAB6L-xx series interconnect cable to the 6-pin connector on the DDCS25.

The BLACK and BROWN wires enable power to the altimeter device when they are connected together. They may be connected to an On-Off switch.

The RED and ORANGE wires connect to the first deployment charge, the one that fires at apogee.

The YELLOW and GREEN wires connect to the second deployment charge, the one that fires during descent as selected by the user.

To turn the unit on, connect the BLACK wire and the BROWN wire together. Typically these wires will connect to a normally-open On-Off switch or other device. Or the two wires simply may be twisted together. The unit sounds out a long pulsating beep when powered up, to indicate proper operation. 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 flashbulbs (or low-current electric matches at a safe distance) are connected (don’t connect anything quite yet), 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.

SETTING THE SECOND OUTPUT VALUE

When viewing the front of the DDCS25 (with the cable connector at the top, and the battery holder near the bottom), a four-pin square connector is located below the right end of the battery holder. 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 (Radio Shack Cat. No. 276-1512 or equivalent) 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, 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, the second deployment charge will fire two seconds after apogee (two seconds after the first charge fires). With this setting it is possible to use the second output as a backup for the first charge. With this setting it is possible to create an apogee deployment sequence that is implemented with two timed steps.

When two jumpers are installed vertically, on both the left two pins, and on the two right pins, the second deployment charge will fire after apogee during descent at 150 feet below apogee. One of the many possibilities for this setting 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 output switches) 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 DDCS25 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.

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.

NOTES ON MOUNTING AND INSTALLING

The DDCS25 may be installed lengthwise in a small-diameter rocket tube. It will fit lengthwise in a 38 mm ID tube. Also, it may be mounted lengthwise on either side of a center plate inside a 54 mm tube. In larger tubes it may be mounted flat against a bulkhead. 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. Do not enlarge the mounting holes, and do not use Velcro.

An Altimeter 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.

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 four 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 four body diameters" rule may be reduced to one or two.

LIMITED WARRANTY AND DISCLAIMER

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.

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.

ADDITIONAL ACCESSORIES

Additional CAB6L-24 Interconnect Cable
Price: $7.50 - 24 inches long. Connects DDCS25 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 DDCS25 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 DDCS25 when used in a dual redundancy backup system is the ALTS25. 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 ALTS25 measures altitude to 25,000 feet with deployment that functions to 60,000 feet. The ALTS25-60K extended version measures altitude to 60,000 feet with deployment that functions to 100,000 feet.

ALTS25 Maximum Altitude Altimeter with Dual Deployment™
Price: $99.00 - Includes CAB6L-24 Interconnect Cable and GP-23A Battery.

ALTS25-60K Maximum Altitude Altimeter with Dual Deployment™
Price: $134.00 - Includes CAB6L-24 Interconnect Cable and GP-23A Battery.

www.adeptrocketry.com 3/29/13