New to robots, need some guidance :)

Hi everyone!

First time on here,

I have recently been playing around with designing and building my own beetleweight as I have access to mill/lathe/laser machine at my work.

Nothing fancy or even battle ready to begin with, basically just a wedge ram bot, until I get the hand of things.

I've been looking through the forum and browsing internet, and have some idea of motors to use (something like 12V DC 1000rpm), but can anyone advise me on what ESC is suitable, controller/reciever & what mAh lipo's I'd need.


Thanks in advance :)

Hi Shrimpo!

We're currently finishing the build of our first featherweight so we can't tell you too much here but we can help with the basics.

On ESC's, there's a few things you need to check: The current draw of your motors, if the ESC has a BEC, if it can do reverse and whether or not your motors are brushed or brushless.

On the first point, you'll want to ensure that your ESC is rated for a higher current than your motors draw. So for example, if the motors are drawing 10 amps you'll want an ESC that can do 15 amps to make sure it always holds up. ESC's have to maximum current ratings, one for standard use and one for peak use, so make sure the standard use is higher too! Plus, robots tend to draw a lot more current when pushing as a result of stalling.

On the second point, you'll probably want to make sure it has a Battery Eliminator Circuit (BEC). These basically provide power to your receiver at a voltage (around 5v) that it can withstand.

Third, you'll need a ESC that can do reverse. It sounds silly but a lot of them don't since they're designed for RC plane rotors.

Finally, the Brushed/Brushless issue. As a general rule, brushless motors are more powerful than brushed, but can be harder to work with thanks to their increased torque. Brushless motors don't work on brushed ESC's and vice-versa. Easiest way to be sure is to check the number of wires coming out of each: Brushless motors and ESC's have 3 connecting wires, whilst Brushed only have 2.

For controllers and receivers, it really depends how fancy you want to go. We use a Turnigy AI-6, which seems to be doing well but other people use far fancier systems, as when the controller goes the robot is done for! Hobbyking is a good place to look for these, and pretty much any parts you might need. I'd recommend getting a package that includes both the receiver and transmitter so that you know they'll work together, and make sure it has enough channels and uses legal frequencies. Check the FRA rules if you're not sure which frequencies are allowed for your weightclass.

As for batteries, just make sure you've got something that's of the right voltage for your system. LiPo batteries are often calculated in cells, each cell being 3.7v. You don't need to use LiPo batteries, as although they certainly have a lot of power for their weight, they can be quite dangerous if not looked after properly and run the risk of catching fire. When it comes to mAh, it's generally the higher the better, just make sure your ESC's can hold up to it!

As an aside, this Instructibles article might prove rather helpful. It's intended for RC planes but it's useful for understanding the basics and I certainly wish we'd found it easier in our build: http://www.instructables.com/id/Begi...?amp_page=true

Hope all this helps!