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Old Jun 16, 2012, 11:02 PM
Semper Fi
GreenAmphibian's Avatar
Northern Triaid North Carolina
Joined Jun 2008
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Help!
Brushless switching

I have a problem that I need help with for my 1/16 LVTP-7. I need to be able to control two brushless systems with each one having two ESC's and Motors and their own 11.1 Li Po's. One system is for the tracks and one is for the water jets. I would like to use the El Mod system for the main board and for its other functions, but it only supports two brushless motors/ESC's. Can I use an electronic switch on the boards output to switch between the two drive systems, or is there an easier way to do this? Can I do this without having problems with the ESC's that are switched out? Thanks for any help you can give me.

Herman
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Old Jun 17, 2012, 07:17 AM
RIP Ric
Andy W's Avatar
Marietta, GA
Joined Jun 1999
43,312 Posts
Not following your description. Can you not simply run each pair in parallel?
Perhaps post a diagram?
..a
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Old Jun 17, 2012, 10:50 PM
Semper Fi
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Northern Triaid North Carolina
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The pairs have to operate individually from each other. Two for tracks (L&R) forward and reverse, and two for the water jets, forward only. Although the systems are normally used separately, they could work in conjunction with each other coming out of the water.
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Old Jun 18, 2012, 04:40 AM
Registered User
UK
Joined Aug 2000
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Herman,
You can use electronic switches. Inserting them into either the battery positive or radio signal leads will work. The 1st requires a high current switch. The 2nd will make the motor beep when the signal is cut off. With both I'd expect the ESC's to require that you close the throttle to arm them when you switch them on. To operate both pairs simultaneously or independantly you will need two switches and probably two 'switched' radio channels.

Another approach is to put the water jets and tracks on different 'proportional' channels. For instance, if you use the right stick for tracks you could use the left stick for the water jets. This has some mixing challenges if the jets need differential thrust for steering. What Tx do you have?
Regards, David.
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Old Jun 19, 2012, 08:26 AM
Semper Fi
GreenAmphibian's Avatar
Northern Triaid North Carolina
Joined Jun 2008
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David,
I am using a Futaba 9C radio. I am using the radio mixing now, but I want to add IR battle capabilities to the model and need to use one of the IR tank systems in order to do that. I am trying to work within the capabilities of that kind of electronic control since I am a firm believer in the KISS principal. How would the two switches be set up?
Herman
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Old Jun 19, 2012, 08:53 AM
"Simplify, then add lightness"
Raleigh,NC
Joined Nov 2000
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This device would do what you are looking for. It has outputs for 4 servo/esc signals and two groups of 4 inputs. It uses a spare channel to switch either one or the other groups of inputs to the outputs. Using one of them would allow either one or the other esc to be selected. If you needed the option of using both drives at the same time you would need two of them. You would also need either another spare channel that was always off or else a servo tester to feed into the inputs to provide a neutral or off signal so that the escs do not have to be re-armed when they are switched. http://www.pololu.com/catalog/product/722
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Old Jun 19, 2012, 09:42 AM
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UK
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Herman,
People like Dimension Engineering sell electronic switches. You just plug each into a channel (eg: Ch5) and toggle the switch to enable/disable. There may be a switching threshold that has to be set. If you switch the positive lead between the battery and ESCs then the signal leads would go to the tank system and obey whatever comes through that. I know nothing about the tank control system but I'd expect the two switching channels to bypass that.

To use the 'separate sticks' approach I was thinking you could use say Ch1 & 4 to control your jets with a 'v-tail' type mix assuming you need differential thrust for steering. These two channels would bypass the tank system. All other channels could go into the tank control board.
Regards, David.
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Old Jun 19, 2012, 01:45 PM
Semper Fi
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Northern Triaid North Carolina
Joined Jun 2008
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Thanks guys! You have given me a couple of things to chew on. Now to see which one would be the best approach for my application.
Semper Fi,
Herman
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