Adept Rocketry - ST236 Instructions and Data Sheet
Dual (Two-Event) Staging / Deployment Timer
Copyright © 1993-2003, All Rights Reserved
The two-event ST236 Staging / Deployment Timer is capable of supplying very high current to igniters or deployment charges. It arms at the first instant of liftoff, and each output fires individually after predetermined periods of time. It may be used for staging multi-stage rockets, air starting motors, or for controlling parachute deployment at a given time(s) after liftoff. The Timer can also drive or furnish power to other types of electrical or electronic devices. It may be used for combinations of sequential ignition, staging, air starting motors, multi-event deployment (Dual Deployment™), etc.
The ST236 Timer is offered in two different configurations with different current supplying capabilities. The model designations are ST236LH and ST236H. The ST236LH is pictured above. The ST236H can be identified by the absence of a couple of components, the large blue capacitor above the right end of the battery holder is missing, and the legend "EXTERNAL BATTERY REQUIRED" is visible. Also missing on the ST236H, the small 2-pin connector just below the red 6-pin connector. Both models are capable of supplying high current (up to 12 amps of current) when used with an external battery, to fire virtually any type of igniters or deployment charges, depending on the type of load driving battery used, alkaline, nicad, etc. The designation LH stands for low current or high current. When used for low current the ST236LH device does not need an external battery. The small on-board battery along with the large electrolytic capacitor are used to fire flashbulbs or low-current electric matches such as the Davey Fire brand 28B or 28BR electric match. When used for high current, the LH device requires use of an external battery. The ST236H device (lowest cost) always requires use of an external battery even if used to fire only low-current igniters or deployment charges.
A 12-volt lighter battery is used to keep the microprocessor system running glitch free during the times of heavy current demand on external load-driving batteries. Current to a low-current load is actually supplied by the large electrolytic capacitor on the ST236LH. The lighter battery is always used, even when an external battery is required. Times are programmable to values in excess of 10 minutes in increments as fine as 1/100 second. The length of time in which the outputs remain energized is also programmable. Programmed settings are nonvolatile, and they are not affected when the device is turned off or when the batteries are removed. The settings remain indefinitely until they are reprogrammed.
The outputs may be used to drive light bulbs, or electric motors for functions of a mechanical nature. They can also be used to furnish power to other electric or electronic devices, with fully programmable on-times and off-times. Programming and testing is simple and quick. The ST236 uses Adept’s patented acceleration sensing system ("A" Switch™) for simplicity and to insure safety. If acceleration and movement upward does not continue for at least 0.3 second, the timeout operations will not be enabled. The system cannot be set off accidentally by dropping, shaking, bumping, falling over, etc. Times start from the first moment of liftoff.
This microprocessor based device measures 1.4" wide by 0.65" thick by 3" long. It fits in a tube with a minimum ID of 1.5 inches (38 mm). It will also fit on either side of a center plate inside a 54 mm ID bay, three inches long. Its weight with battery installed is only 1.2 ounces. An Adept CAB6L-xx series Interconnect Cable Assembly (or CAB6BC) is used to control power, and for igniter (or deployment charge) connection. Included is circuitry to detect and separately indicate when the igniters have continuity. The battery life for this product is many hours, so you need not be concerned about how long your rocket sits on the launch pad after being connected to igniters and powered up.
NOTE 1: The circuitry on the ST236 may be sensitive to noise and static when being held. Always handle this device by the edges when testing or installing to avoid touching any of the circuitry during normal operation. Avoid carpeted floors and other sources of static electricity when handling and testing the device. Never store the device in a clear plastic bag; however, pink-colored or smoke-colored antistatic bags are ideal. Storage in a small cardboard box, or wrapped in a paper towel inside a plastic bag is acceptable. Do not use Velcro to secure the device. Use care to keep the device clean and dry.
NOTE 2: The 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 Timer must be installed in an area that is totally sealed from rocket motors and charges. After passing wires through holes in bulkheads and such, seal them with epoxy or removable putty.
The procedures below may be followed as a tutorial.
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 a CAB6L-xx Series cable or special CAB6L-12 cable (Adept CAB6BC Cable / Battery Clip Assembly Kit, included) to the 6-pin connector on the upper end of the device. The CAB6BC supplied with the ST236 is actually a kit that may be configured in several ways. If using an ST236LH in Low Current Mode you may use a CAB6L-12, CAB6L-24, or CAB6L-36 cable. The CAB6BC cable becomes a CAB6L-12 cable when you install the 12" RED wire (between the BROWN and ORANGE wires) and the 12" BLACK wire on the other side of the BROWN wire. When using the ST236LH in Low Current Mode assure that a jumper is installed on the 2-pin connector just below the red 6-pin connector.
When using the ST236H, or when using the ST236LH in High Current Mode, assemble the CAB6BC with the two special "doubled-up" RED and BLACK wires that include a Battery Clip for a 9-volt size external battery. The extra RED (positive +) and BLACK (negative -) wires plug on to the external 9-volt size battery. If you wish to use a different type of external battery, then cut the wires close to the battery clip and use the short RED and BLACK wires to connect to the external battery (3 to 12 volts). When using the ST236LH with an external battery in High Current Mode assure that the jumper is REMOVED FROM the 2-pin connector just below the red 6-pin connector.
Powering Up the Timer
The device will power up when the ends of the BLACK wire and the BROWN wire are connected together. An On-Off switch may be used. When the device is powered up, it beeps every second to indicate normal operation and that it is now waiting for rocket liftoff. This is also the mode used for testing the device with or without a load connected. NOTE: when the ST236LH is turned off, it will continue to run for an additional 15 seconds or so until the large capacitor is discharged.
Testing the Timer
The ST236 is preprogrammed in the factory as follows. Output # 1 will turn on at 3 seconds and remain on for 1 second. Output # 2 will turn on at 6 seconds and remain on for 2 seconds. To test the settings with no loads connected, power up the device, and then close the Acceleration Switch for at least 0.3 second to simulate a valid liftoff. At the end of the Output # 1 time setting (3 seconds) there will be a beep, then a boop (lower tone beep) 1 second later, to indicate that Output # 1 turns on 3 seconds after liftoff and stays on for 1 second. Then at 6 seconds there is another beep to indicate that Output # 2 has turned on. Two seconds later, the boop indicates that Output # 2 has turned off. Then after a pause, the device returns to normal operation.
NOTE: the device is triggered when the Acceleration Switch remains closed for at least 0.3 second. It is virtually impossible for the device to fire due to dropping, shaking, or bouncing. Try it some time. However, when mounted in a rocket with the cable connectors toward the nose of the rocket, and the Acceleration Switch toward the aft end of the rocket, the device will start when the rocket launches. The rocket motor must have a minimum thrust time of 0.3 second, and the rocket must accelerate with sufficient G force for a minimum of 0.3 second. This requirement is met by virtually all commercially available rocket motors that are used as recommended in rockets that have a maximum recommended weight. WARNING: don’t use this device in an experimental vehicle designed to operate with a slow takeoff. And don’t use motors that have an extremely short burn time.
SAFETY SAFETY SAFETY
Never install the ST236 Timer in a rocket without first testing both of its controlling outputs. Always test before each flight with flashbulbs or low-current electric matches similar to the ones that will be used in the actual flight. Connect and enable igniters only during testing, and as one of the last steps before launching. When installing, especially in large vehicles, for maximum safety, it is important to use additional safety gimmicks such as quick disconnects, and igniter shorting clips. With the rocket on the launch pad, only then enable the igniters or deployment charges and turn on the power. Then as the last step remove any igniter shorting gimmicks.
PROGRAMMING THE ST236
Please read through the following information before attempting to program the ST236.
To program (permanently change) the time settings, either Output # 1 or Output # 2 must be selected, and the ST236 must be put into Programming Mode. Output # 1 is selected by shorting together the two Output # 1 connections. Output # 2 is selected by shorting together its output connections. Note: Programming should be done in Low Current Mode (no external battery) when programming the ST236LH. The ST236H must be programmed with the external battery connected. Be sure to remove the short circuit connection across Output # 1 or Output # 2 before testing the ST236 with an External Battery. If neither output is shorted, or if both outputs are shorted, programming is disabled.
To put the ST236 into Programming Mode, the device must be powered up while the Acceleration Switch is held closed. Programming is then done via the Acceleration Switch. The Switch will be used as if it is a push button switch. The Switch state is normally open with the brass bar up against the battery holder. Push the brass bar toward the microswitch to close it, or close it via its chrome lever. But be careful not to damage the assembly.
A better way to close the switch is to use your right thumb to push up the short end of the brass bar. Place the device on a flat insulated surface with the cable connector away from you and the switch toward you. Hold it in place with your left forefinger on the battery. With your right thumb push the short end of the brass bar upward. This movement can be quick and precise. Practice this a few times.
Programming is done by closing (and quickly releasing) the Acceleration Switch once to start the time setting, and again at the end of the desired time. At the end of the desired time, the switch is closed again but not quickly released. The amount of time it is held closed the second time determines how long the output stays turned on. See: Special Programming Considerations below.
When the Timer is powered up in programming mode, there will be a beep, followed by a long beep. Then the Timer will start buzzing to indicate programming mode. You can use the second hand of a watch or clock to indicate times, or you can simply count seconds if real accurate settings are not important.
Programming the device takes a little practice at first. But after a few tries, it will be very quick and precise. Turn off the Timer if not already off and wait for the beeping to stop. Close the Acceleration Switch, and turn on the ST236 while the switch remains closed. You may release the switch as soon as you hear a beep. After the long beep the device will start buzzing. It will take two closures of the Switch to program the time setting, once at the beginning and again at the end. Watch the second hand of the clock for start and stop times.
Press and release the Switch to start the time. There will be a beep, and the buzzing will continue. At the desired time, press the Switch again (another beep), but do not release until the desired amount of active-on time is complete (another beep). After a pause, the Timer will change back to normal mode, beeping once a second.
If neither output is shorted (selected), or if both outputs are shorted (selected), programming is disabled, but the buzzing and beeps still work the same. You may practice programming without actually changing previous programming by selecting neither output (or both).
Example: to set the Output # 1 time to 3 seconds after liftoff and to stay on for 1 second:
Turn off the ST236 and wait for it to stop running. Connect the RED wire to the ORANGE wire. This shorts the connections for Output # 1, and selects it for programming. Close the Acceleration Switch, and turn on the ST236 while the switch remains closed. Release the switch as soon as you hear the first beep. While the device is buzzing (and while watching the second hand on a clock), at an appropriate start time, close and immediately release the Switch (beep). Then when the second hand reaches 3 seconds later, close and hold for 1 second this time, then release again (buzzing stops). The setting is now 3 seconds with a 1 second on time, and will remain this way until you change it again. Now disconnect the RED and ORANGE wires.
Example: to set the Output # 2 time to 6 seconds after liftoff and to stay on for 2 seconds:
Turn off the ST236 and wait for it to stop running. Connect the YELLOW wire to the GREEN wire. This shorts the connections for Output # 2, and selects it for programming. Close the Acceleration Switch, and turn on the ST236 while the switch remains closed. Release the switch as soon as you hear the first beep. While the device is buzzing (and while watching the second hand on a clock), at an appropriate start time, close and immediately release the Switch (beep). Then when the second hand reaches 6 seconds later, close and hold for 2 seconds this time, then release again (buzzing stops). The setting is now 6 seconds with a 2 second on time, and will remain this way forever until you change it again. Now disconnect the YELLOW and GREEN wires.
With the Timer beeping normally, test the settings. Close the Acceleration Switch for at least 0.3 second. At the end of the Output # 1 time setting (3 seconds) there will be a beep, then a boop 1 second later, to indicate that Output # 1 turns on 3 seconds after liftoff and stays on for 1 second. Then at 6 seconds there is another beep to indicate that Output # 2 has turned on. Two seconds later, the boop indicates that Output # 2 has turned off. Then after a pause, the device returns to normal operation.
Special Programming Considerations
When programming outputs, do not allow either output (especially the first to fire) to remain on longer than necessary. A one-second drive time is more than sufficient to fire virtually any igniter or deployment charge. Some igniters do not burn up totally when fired (the wire does not open up), and they may continue to draw excessive current.
When using the ST236LH in Low Current Mode (no external battery) to fire flashbulb or low current electric match charges, the On Times should be only a small fraction of a second. They fire very quickly. So to program the ST236LH in Low Current mode do the following. While the device is buzzing (and while watching the second hand on a clock), at an appropriate start time, close and immediately release the Switch (beep). Then when the second hand reaches 2 seconds later (or whatever you wish to set the time to), close and immediately release again. The On Time will be about 1/20 second or so.
When using the Timer in High Current Mode to supply power to other devices, or to run electric motors, the On Time may be any value up to 10 minutes. The amount of current drawn during this period must be low enough (one amp or so) so that the on-board drivers do not over heat.
TEST THE ST236 WITH REAL LOADS
The outputs may be tested with light bulbs, flashbulbs, electric matches, Estes igniters, etc. Light bulbs are the least expensive alternative for general purpose testing. But never assume that a particular type of igniter or charge or other device will work with your battery without first trying them. Warning: never install this device in a rocket without first testing its controlling outputs. Always test before each flight. Also, backup systems and/or instrument redundancy (use of two similar systems in the same rocket) are recommended.
When turned on, the Timer beeps once a second to indicate normal operation with no loads connected. When an igniter or deployment charge is connected to Output # 1 only, RED and ORANGE wires, the single beeps of once a second, change into double beeps to indicate continuity of the igniter or deployment charge on Output # 1 only. When Output # 2 only is connected, YELLOW and GREEN wires, triple beeps indicate continuity of Output # 2 only. When both outputs have loads connected, the beeping pattern is 4 beeps.
If you wish to use a light bulb for low cost general testing in Low Current Mode, then use a low-current 6 to 12 volt bulb in place of a low-current igniter or flashbulb. It probably will just flash. In High Current Mode, in place of a high-current igniter, use a bulb with a voltage rating similar to the voltage of the external battery being used. It should stay turned on for the full on-time setting for the output. But always test at least once or twice with the same type of igniter that will be used in an actual flight. The proper way to test if a device can always fire an igniter or deployment charge is to try it with two in parallel. If it can usually fire two, then it should always be able to fire just one. The proper way to test if a device can fire two igniters or deployment charges in parallel is to try it with three in parallel. If it can usually fire three, then it should always be able to fire just two.
MOUNTING AND INSTALLING
This device must be installed lengthwise in a rocket tube with the acceleration switch toward the bottom. A couple of thoughts on mounting and installing this device used successfully so far are included here. The ST236 fits inside a 38 mm ID tube. Bulkheads, blocks, a fixed nosecone, etc. can be used to secure the Timer. The ST236 also may be mounted on either side of a center plate inside a 54 mm ID tube. When it is to be used in larger diameter body tubes, it may be mounted on basswood, plywood pieces, etc. that connect to bulkheads or a modified nosecone. Or it may be installed inside a 38 mm tube that is mounted to a plate. Whenever possible, support the lower end by mounting it against a bulkhead. The mounting holes are .090 inch diameter for #2 hardware. Use #2 screws, standoffs, and hexnuts when mounting to wood or other material. Do not enlarge the mounting holes, and do not use Velcro.
The device may be placed inside a 38 mm tube (that has a bulkhead at one end and a removable cap at the other) and secured in the parachute area of a larger tube. The parachute (and wadding if any) would fit in the remaining area beside the mounting tube. Care must be taken to assure that the parachute (and wadding) will still deploy properly. In some larger rockets, rocketeers have devised clever doors or hatches on the outside of the airframe that allow access to the Timer which is mounted between the airframe and the motor mount. The Timer may be mounted in the second or third stage of a rocket.
Note: the higher the weight is in the vehicle (CG closer to nose end) the more it adds to overall rocket stability. Mount the ST236 in the third stage for best stability. This allows direct connection to the third-stage igniter, but a "slip disconnect" is necessary in the wires that run down to the second-stage igniter. The wires slip loose when the stages separate. If the device is mounted in the second stage, then a "slip disconnect" is necessary in the wires that run up to the third-stage igniter. Adept CAB2-xx and CAB2-xxD cables may be used. The Timer must be installed in an area that is totally sealed from rocket motors and charges. After passing wires through holes in bulkheads and such, seal them with epoxy or removable putty.
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 judgement 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.
ST236LH Dual (Two-Event)
Staging / Deployment Timer
ST236H Dual (Two-Event) Staging / Deployment Timer
Additional CAB6BC Cable/Battery Clip Assembly Kit
CAB6L-24 Interconnect Cable
CAB2-12D - 12-inch CAB2-12
Interconnect Cable with 12-inch Disconnect Leads
Additional GP-23A Alkaline Lighter Battery - Price: $2.25
GP-23A50 Alkaline Lighter Batteries (box of 50 at 50% Discount) - Price: $56.25
The GE/Sanyo 9 volt size nicad batteries are made with cylindrical cells and have very low internal resistance. They can supply up to 15 Amps of current for short periods, making them ideal for many rocketry uses.
N-6PT GE/Sanyo 9 Volt Size Rechargeable Nicad Battery - Price: $16.79 out of stock
BC1 Premium Battery Clip for 9 Volt Size Battery (6-inch leads) - Price: $1.15
WY-29V Charger for Two 9 Volt Size Nicad Batteries (plugs into wall socket) - Price: $14.50
Shorting Jumpers are used on some devices to program certain values or functions. One Jumper is used on the ST236LH when it is used without an External Battery in Low Current Mode.
Shorting Jumpers - Price: $1.39 per pack of 10.
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.
The ST236 is also available in another form as the ES236 Dual Sequential Stager™. Unlike a Dual Timer, a Dual Sequential Stager™ detects liftoff by first detecting acceleration, and then fires the second stage when it detects deceleration of the first stage due to motor burnout. This is especially handy when the exact burn time of the first stage motor is not known, as with a hybrid motor. Also, an amount of coast time may be added before ignition of the second stage. Then if the second stage properly ignites and properly accelerates, the third stage ignites on burnout (deceleration) of the second stage. And again an amount of coast time may be added before ignition of the third stage. An Electronic Stager™ or Dual Sequential Stager™ can also be used to control air-start sequencing of motors.
ES236LH Dual Sequential Stager™
ES236H Dual Sequential Stager™