Feather weight speed controllers

[calumco]

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?

[maddox]

Feather weight speed controllers

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.

[geeza]

Feather weight speed controllers

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.

[woody]

Feather weight speed controllers

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.

[mattan]

Feather weight speed controllers

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 -

[woody]

Feather weight speed controllers

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, 200

[m2xt]

Feather weight speed controllers

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?

[calumco]

Feather weight speed controllers

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?

[woody]

Feather weight speed controllers

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, 200

[leorcc]

Feather weight speed controllers

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.

[woody]

Feather weight speed controllers

im making a kind of prototype robot which runs on two 9.6 volt drill motors and gearboxes?
Simply replacing the drill chuck with a wheel of between 80mm - 100mm dia is standard practice in bot building.

[john_frizell]

Feather weight speed controllers

Good decision not to go with the Viper M tronics for a feather. I once did a 6 kg feather with them, runing 2 x 9.6 volt drill motors. They worked but they were not quite enough and sometimes went into thermal cutout. I retired them to a 1.3 kg robot driven by electric screwdrivers and they have been performing well ever since.

[philip_taylor]

Feather weight speed controllers

Has anyone ever tested the Sabertooth controllers with a data logger to find out if they perform to their reported amperage in the arena?

[typhoon_driver]

Feather weight speed controllers

Sabretooths in my experience are far short of their 25Amps rated. They have blown twice on me so I have given up and gone back to 15amp electronize. Only blew on of them for the first time this weekend and even then its only the relay which will take a half hour to replace.

[m2xt]

Feather weight speed controllers

Philip, I have and they unlike another well known brand I could mention do perform to their published spec and that is also guranteed by Dimension Engineering. I have run a pair of 15A electronize controllers with eight 30W motors in parallel and never blown a relay. As I have mentioned before Gary, its all about knowing what your motors take under all conditions especially stall current which is what is the controller will see when suddenly reversing direction.