Author Topic: signal monitoring  (Read 3487 times)

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Offline TTU_TeamTopic starter

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signal monitoring
« on: April 09, 2006, 09:16:41 PM »
Hello, I‘m trying to make a safety feature on a remote control submarine that will sense when the sub is out of transmittion range and blow the ballast tank and send her to the surface for recovery. I am using a motorola HC12 and the Hitech Laser 6 transmitter and reciever. Basically I want to poll one of the A/D ports on the MCU and when there is no input, jump to a subroutine to blow the ballast. Is there something I can hook up that will output a voltage if there is a signal. Please let me know how to accomplish this, or if there is a better way. Thanks,
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Offline cjwillms

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Re: signal monitoring
« Reply #1 on: April 09, 2006, 10:48:50 PM »
The only solution I can see would be to somehow configure your Laser 6 to send out a signal every minuet or so. Then, you’d have to reprogram your MCU to wait for any signal. If one doesn't come, for say 2 minuets, and then your sub should blow the ballast.

If you can't configure your Laser 6 to do that, you'd have to build a transmitter that operates on the same frequency that sends the signal, telling your sub that it's in range.
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Offline Admin

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Re: signal monitoring
« Reply #2 on: April 10, 2006, 04:57:19 AM »
I will actually be working on something similar for the Navy in a few months . . .

So what you need to do is set up a timer on your microcontroller. Every time your microcontroller recieves a command, have the timer reset to zero. If the microcontroller doesnt recieve a signal for some set amount of time (5 min? 10 min?), have it trigger the recovery floating.

So for the microcontroller to detect a command from your laser 6, read and use this circuit:
http://www.societyofrobots.com/remote_control_robot.shtml
Scroll down to the bottom until you see 'Optional: Teleoperation' and you see a schematic.

Basically every high voltage on a specific input pin should reset your timer variable.

And if say the recovery must triggerr, what you then do is output a voltage to the gate of a MOSFET
http://www.societyofrobots.com/electronics_tutorial.shtml#mosfet
In serious with the MOSFET would be your power, ballast blow thingy, and ground.
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Offline kazzer

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Re: signal monitoring
« Reply #3 on: June 25, 2008, 07:56:55 AM »
There are failsafe systems built into a number of gizmos used in model submarines these days.

See the Micro Viper Electronic Speed Control. http://www.caswellplating.com/models/esc.html

and Mtroniks - Micro Failsafe  at approx $20

These are connected to the ballast tank servos and when loss of signal occurs, they blow the tank after approx 7 seconds.


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