Is it ok to use a RC heli board as my main board? and how to watreproof motors other than a magnetic coupler?


#1

Hey i have this broken 3.5 channel R/C heli with infrared transmitter, the main chip board works perfectly and i have tested it out with a 3800kV brushed dc motor and it works good, as the heli needs to control the climb rate it has an ESC to control its motors, and this in-built esc works correctly with the motors, all i am wondering about is if it will work in the long run and if i am giving enough amps to my motor, how can i know if i am underpowering them or not? my emitter has a 15 feet range i am expecting about 7 feet underwater , to tackle this i will keep the receiver on top and send its contacts down with my tether which will give the ROV a more vast range,using this board i will control 3 motors and 2 motors will have speed control, the battery is a 180mAh LiPo which will be replaced by a 5000mah LiPo with the same discharge rate as the prev battery, is this a good way to contol my rov thrusters or am I TOTALLY out of track?

secondly what are the various ways of waterproofing a motor other than magnetic couplers, i cant buy bilge pumps from where i stay because i will have to import them and they become too costly then and out of my budget.


#2

Tarneil,

It's hard to say exactly what to expect with that hardware, but if it's from an RC helicopter, you probably won't be able to reverse the direction of the thrusters. Also, in water they will draw a lot more current, so plan for your power supply and ESC to be handling a lot more power then usual. I usually try to get the lowest possible KV rated motor I can find, because in water you almost always want more torque and less speed.

You can waterproof a brushless motor fairly easily. The two things you have to worry about are corrosion (over time) and electrical shorting. Corrosion issues can be somewhat mitigated by spraying the motor with silicon spray before a dive, then rinsing and drying them with fresh water after the dive. For electrical shorting, coat all solder joints (and other locations of un-insulated wire) with several layers of liquid electrical tape.

Good luck with your project!

Eric


#3

Thank you for your reply Eric, but a lower kV motor usually is much bigger than a higher one as the wire is thicker inside with less coils, this adds weight to the rov and making it neutrally buoyant becomes that much more tougher. And the higher torque motors require more current = to a bigger battery pack, can you suggest me a good torquey motor with less current draw? typically how much should the kV range of the motor be to work as a thruster?

To decrease electrical shortages i will cover all electrical components in hot glue is that ok? and using silicon spray each and evry time before a dive will become too tiring, as i will have to open the closed motor every time to spray it, what else do you recommend? and i wanted to know if you were making a low budget ROV which controller would you use as the main brains?

Thanking you in advance,

tarneil


#4

Hey eric tackled the reverse problem with a switch program which i will put on a ATTiny85( http://www.atmel.com/devices/attiny85.aspx) from atmel, this gives me motors with reverse with ESC. I will use the heli board as an experimental board and Post back with the results but please give me a reply on my previous posts. If the heli board yields results i will put it on my rov and if i get success i will post how i made it thru.