motor controler for bilge pump rov

Forum 2005-2010 (read only) Hardware Interfacing
1

I am building an ROV i need to run 2 bilge pumps that draw 5 amps 7 max per motor. i need it to be bi directional and variable speed. i wil be running the motor off of a 75 foot run of 10 awg wire ran to a 12v car battery. The controllers will be housed in a sealed pvc pipe so low heat would be ideal. out of these or any others around the web which would best fit my needs im using a uno so the less pins the better.

option 1: http://www.robotshop.com/dimension-engineering-sabertooth-2x10-1.html

option 2 : http://www.robotshop.com/pololu-dual-motor-driver-9a-2.html

option 3: http://www.robotshop.com/cytron-5-19v-10a-brushed-motor-controller.html

2

Heat is pretty much a fact of life with such things.... how long does it need to run for?

3

I am using the Pololu parts for the same exact project. (testing the ROV thrusters « Projects)

The STMicro VNH2SP30 will handle 5 amps continuously with no heat sink. The Pololu notes say it will do much more than 5A.

At 6 A, the chip gets just barely noticeably warm to the touch.

4

these use 2 pins per motor right? one pwm and one for direction

5

Right., as long as you arrange for an external inverter. The Pololu board has separate A and B inputs. If you need A = not B at all times, as I do, you can use an inverter and avoid using an extra pin on the Arduino.

6

i want each motor to be controlled independently so it would be 3 per motor for a total of 6 2 pwm and 4 digitial?

how did you build your inverter and im thinking of upgrading to a mega so i may not have to worry about pins

7

I used a 7414 TTL hex inverter. It cost about 47 cents.

8

mind sharing how u wired that up and do u have a method for depth detection

9

do u have a method for depth detection

What depth ? well there are many sensors like the ping which you can use to detect depth :slight_smile:

10

depth in water i know you can use a pressure transducer but they cost 120+ which is to much. i would be going about 10 feet deep so i need to measure about 7 psi. i am looking in to using a electronic oil pressure sensor which is about 15 i know it outputs 0-5v and is rated for 80 psi i need to look into if it will work for me. is the uno sensitive enough to work between 0-100 microvolts 1-8 psi or will i need to amplify it?

11

method for depth detection

Not as yet, but I have a vague plan to use something like this Freescale MPXM2202GST1. Mouser has them priced at $6 to $11 depending on specifics.

http://www.freescale.com/files/sensors/doc/data_sheet/MPX2202.pdf

A 200 KPa part would measure to around 18 metres depth -- deeper than the lake I want to run in.