Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: TTU_Team 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,
>
>
> ...matt
-
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.
-
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.
-
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 (http://www.caswellplating.com/models/esc.html)
and Mtroniks - Micro Failsafe (http://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.