Tweet
What should a Submarine Deadman Timer be and where can I get one?
A Deadman Timer should be a "simple" device that will reliably run on it's own power and produce some kind of activity at the end of a long (hours) delay. Possibly releasing an emergency buoy(s) that are tethered securely to the sub and can be used as a location device for a sub sunk. Just like we have on the 1:1 boats.
A Deadman Timer would NOT replace the Failsafes that are available but would try to cover the problem of a sub stuck on the bottom for some reason and an emergency blow initiated by a Failsafe would not release it. Most likely the failsafe will have initiated a blow already before the Deadman Timer released it's buoy.
I had originally pursued a mechanical clock type of mechanism. I even located such a device but they were priced at $225!
I used to fly free-flight (no R/C) airplanes as a kid and remembered the DTs we used when we wanted the bird to descend for recovery. This type of unit is referred to in the FF world as a "DT" (De-Thermolizer). The early ones were nothing more than a fuse or wick that would slowly burn down to the point were it would burn through the string holding the horizontal stabilizer/elevator thus allowing it to swing to a vertical position.
The DT is an "If all else fails" totally independent approach to trying to find a boat on the bottom that has not responded to anything else for one reason or another.
I've included a URL to a web site that has a device used by the free-flight aircraft hobbyists to bring down their aircraft after a pre-set time delay. The DT (through a servo or other device) causes the horizontal stabilizer on the FF aircraft to flip to a vertical position which forces the a/c to begin a falling-leaf decent.
URL: http://mysite.verizon.net/resrqa3z/airtek/id68.html
I contacted the builder, Ken Bauer, to see if he had a way to extend the time-base increment and maximum time-out. With a firmware change he can program the timer to count in increments other than 30 seconds. He suggests that he could, for example, change the timebase increment to 30 minutes for our application which would give us a maximum time-out period of 20 hours. He could make the timeout whatever we wanted.
What Ken Bauer is offering is a good KISS solution which has been proven in the FF world. If one didn't want to activate a servo, a relay switch type device, or solenoid could be activated instead.
I plan on putting the DT in it's own WTC along with it's own battery. I plan on either keeping the servo in the DT WTC or possibly extending the servo leads outside of the WTC to a waterproofed servo. Haven't decide which yet though the former approach seems better. I also want to make sure that whatever system I implement it does NOT put a load on the DT battery until Timeout. I want to preserve the battery charge as much as possible. I would consider loading the battery at Timeout, which should be almost never. At that point who cares about the battery condition as long as it will support the Timeout event.
The servo operation is simple and would work for you as is. There are only two servo positions, the normal initial position and the DT or release position. A couple of seconds after DT timeout the servo moves back to the normal position and will not go to the DT position again until after another full cycle timeout. You can restart the timer as many times as you want either by pressing the button or powering it up, but the servo will just stay in the initial position. The timer sends a command to the servo to go to the first position with each reset/power up, but if it is already there it won't move.
Ken Bauer is ready to accept orders for the "SS-DT", (Sub Sunk-Deadman Timer), at $30.00 a piece plus $5.00 shipping and handling. This price does not include the battery or servo, just the Deadman Timer. I've purchased two units already.
Send Checks or use PayPal to:
Ken Bauer
2306 Turquoise Circle
Chino Hills, CA 91709
USA
airtek@verizon.net
949-981-9578
"For mail orders in the US sending a check is good. PayPal works great but please add an extra 2% to the total to help offset the money that these guys keep in the process. Send PayPal to: airtek@verizon.net."
You might want to email Ken when you send in your order and please copy me so I can keep track of who is getting units.
The unit will be programmable in 5 minute intervals. Up to 40 interval counts can be programmed into the SS-DT so that will give us a range of between 5 minutes and a maximum of 200 minutes for Time-outs.
One useful note: The timer provides not only a signal wire to the servo but also a power wire and a ground wire. The signal wire carries the pulse signal that tells the servo where to position it's arm. The power wire is controlled by a mosfet switch so that the servo is only powered on and using battery power during the one second period when it is moving. This is significant because this power signal can be used to control a device directly rather than using a servo. For example, a solenoid could be connected directly between the power wire and the ground wire which would be much simpler than using a servo. This mosfet switch is good for about 200 to 300mA.
If 200 to 300mA is not enough power to drive your solenoid directly you could use it to drive a small relay that could then be used to complete the circuit between a battery and a large solenoid.
Any additional questions PM or email me.
I think you will find the SS-DT a great solution to an old problem. It is vestal and can accommodate may different implementations.
A Deadman Timer should be a "simple" device that will reliably run on it's own power and produce some kind of activity at the end of a long (hours) delay. Possibly releasing an emergency buoy(s) that are tethered securely to the sub and can be used as a location device for a sub sunk. Just like we have on the 1:1 boats.
A Deadman Timer would NOT replace the Failsafes that are available but would try to cover the problem of a sub stuck on the bottom for some reason and an emergency blow initiated by a Failsafe would not release it. Most likely the failsafe will have initiated a blow already before the Deadman Timer released it's buoy.
I had originally pursued a mechanical clock type of mechanism. I even located such a device but they were priced at $225!
I used to fly free-flight (no R/C) airplanes as a kid and remembered the DTs we used when we wanted the bird to descend for recovery. This type of unit is referred to in the FF world as a "DT" (De-Thermolizer). The early ones were nothing more than a fuse or wick that would slowly burn down to the point were it would burn through the string holding the horizontal stabilizer/elevator thus allowing it to swing to a vertical position.
The DT is an "If all else fails" totally independent approach to trying to find a boat on the bottom that has not responded to anything else for one reason or another.
I've included a URL to a web site that has a device used by the free-flight aircraft hobbyists to bring down their aircraft after a pre-set time delay. The DT (through a servo or other device) causes the horizontal stabilizer on the FF aircraft to flip to a vertical position which forces the a/c to begin a falling-leaf decent.
URL: http://mysite.verizon.net/resrqa3z/airtek/id68.html
I contacted the builder, Ken Bauer, to see if he had a way to extend the time-base increment and maximum time-out. With a firmware change he can program the timer to count in increments other than 30 seconds. He suggests that he could, for example, change the timebase increment to 30 minutes for our application which would give us a maximum time-out period of 20 hours. He could make the timeout whatever we wanted.
What Ken Bauer is offering is a good KISS solution which has been proven in the FF world. If one didn't want to activate a servo, a relay switch type device, or solenoid could be activated instead.
I plan on putting the DT in it's own WTC along with it's own battery. I plan on either keeping the servo in the DT WTC or possibly extending the servo leads outside of the WTC to a waterproofed servo. Haven't decide which yet though the former approach seems better. I also want to make sure that whatever system I implement it does NOT put a load on the DT battery until Timeout. I want to preserve the battery charge as much as possible. I would consider loading the battery at Timeout, which should be almost never. At that point who cares about the battery condition as long as it will support the Timeout event.
The servo operation is simple and would work for you as is. There are only two servo positions, the normal initial position and the DT or release position. A couple of seconds after DT timeout the servo moves back to the normal position and will not go to the DT position again until after another full cycle timeout. You can restart the timer as many times as you want either by pressing the button or powering it up, but the servo will just stay in the initial position. The timer sends a command to the servo to go to the first position with each reset/power up, but if it is already there it won't move.
Ken Bauer is ready to accept orders for the "SS-DT", (Sub Sunk-Deadman Timer), at $30.00 a piece plus $5.00 shipping and handling. This price does not include the battery or servo, just the Deadman Timer. I've purchased two units already.
Send Checks or use PayPal to:
Ken Bauer
2306 Turquoise Circle
Chino Hills, CA 91709
USA
airtek@verizon.net
949-981-9578
"For mail orders in the US sending a check is good. PayPal works great but please add an extra 2% to the total to help offset the money that these guys keep in the process. Send PayPal to: airtek@verizon.net."
You might want to email Ken when you send in your order and please copy me so I can keep track of who is getting units.
The unit will be programmable in 5 minute intervals. Up to 40 interval counts can be programmed into the SS-DT so that will give us a range of between 5 minutes and a maximum of 200 minutes for Time-outs.
One useful note: The timer provides not only a signal wire to the servo but also a power wire and a ground wire. The signal wire carries the pulse signal that tells the servo where to position it's arm. The power wire is controlled by a mosfet switch so that the servo is only powered on and using battery power during the one second period when it is moving. This is significant because this power signal can be used to control a device directly rather than using a servo. For example, a solenoid could be connected directly between the power wire and the ground wire which would be much simpler than using a servo. This mosfet switch is good for about 200 to 300mA.
If 200 to 300mA is not enough power to drive your solenoid directly you could use it to drive a small relay that could then be used to complete the circuit between a battery and a large solenoid.
Any additional questions PM or email me.
I think you will find the SS-DT a great solution to an old problem. It is vestal and can accommodate may different implementations.
Comment