Feather weight speed controllers

Im planning to make a feather weight robot, but first im making a kind of prototype robot which runs on two 9.6 volt drill motors, hooked up to one 9.6 volt battery but the problem is i dont know which speed controllers to get.

at a model shop called geedee model shop in nottingham near me, they are selling marine speed controllers running at for example 15A which say.....

The Viper 15 is a reversible marine spec speed controller capable of handling upto 12v 15A max.
NEW built in failsafe to protect against complete loss of signal or when out of range.

would 2 of these do the job? they cost £21 for 1

Any ideas?

If you would try it, I suggest fitting fuses of 15A to the main leads. if these blow a few times in non combat, forget these speedos.

Also, its better to invest in the right stuff from the start, otherwise you end up, like me, with a pile of parts that arent really usable and still sucked my wallet dry.

The other thing is that buying 12V speedos now will limit your upgrade possiblities. It would be better to get some 24V speedos like electronize (availiable from technobots.co.uk). And use them on 12V as 9.6V drills should be able to handle 12V.

As Ed said ...spend a few pounds more and get a speed controller that is commonly used in the Robot community and gives a wide voltage spread.

Ed mentioned the Electronize ...Technobots do a range of controllers e.g.

Sabertooth Dual 25A Motor Controller Universal.

http://www.technobots.co.uk/acatalog/Online_Catalogue_Dimension_Engineering_Controllers _34.htmlhttp://www.technobots.co.uk/acatalog...gineering_Cont rollers_34.html


Double the price of your two Viper Mtroniks Escs
http://www.mtroniks.net/mtroniks_SC_products.asp?CategoryID=1&SubCategoryI D=3http://www.mtroniks.net/mtroniks_SC_...ubCategoryID=3
.... but probably worth it in the long term.

http://www.dimensionengineering.com/http://www.dimensionengineering.com/ same but cheeper price in USD, USD is VEERY low right now, try Sabertooth dual 10A motor driver for R/C - 65 USD - OR Sabertooth dual 25A motor driver - 125 USD -

The Robot Power Scorpion XXL is another possibility ... Ive recently purchased but not yet received this controller.
http://www.robotpower.com/catalog/http://www.robotpower.com/catalog/

Note that it only shipped two days ago ...so no gripes on time....yet:).

(Message edited by woody on April 19, 2008)

Mats, $65 = £34, add to this 4% import duty and then VAT you get £41.55 which is greater than Technobots £38.95 for the 2x10A RC, so how is it cheaper?

thnx very much thats all very helpful, its looking like for now due to the amount of money i have etc ill get the Sabertooth Dual 10A Motor Controller for RC which is £40

But im not 100% sure about something because ive not been doing this kind of thing very long,
but the motors are too fast and need slowing down, can I adjust the settings on the speed controller, or does it work on the more i would push the stick forward the more voltage is supplied to the motors- thus making them go faster?

The speed varies in relation to the stick position .... OFF at centre and a progressive increase as you move the stick foward / reverse ....& left / right if using just one Transmitter stick and mixing the R/C channels.



http://www.4qd.co.uk/robot/start.htmlhttp://www.4qd.co.uk/robot/start.html

(Message edited by woody on April 20, 2008)

There are 3 ways of solving this:

1: get more reduction behind the motor so the wheels turn slower if the motor is running full power (that is the best way, you will have more power and your speed controller(s) have to work less) but unfortunately that is not always possible.

2: reduce the amount of stick travel, make a small plate that fits over the stick with a circle that is less large than the maximum stick. Ive seen some people do that with transmitters that dont have option 3.

3: If you have a transmitter that can do it, change the settings on your transmitter that stick travel is only a certain percentage. With Dual rate you could flick a switch and then have your sticks at a lower percentage if you push it all the way out. I do that with Hannibalito 3, it drives normally at 45% of its top speed unless I flick the switch.