Novice Here - Any Beginner's Advice?

Hi all, I've been a huge fan of robot combat for many years now and have finally decided to build my own and take part. After a brief bit of research I've been told that beetleweight is the best category for a beginner to get into. Supposedly antweights are too difficult to meet the low weight limit, featherweights have a really high skill ceiling, and heavyweights are just too expensive. This is fine by me.

What advice would you be able to give me? I'd like to know where I can purchase parts, what sorts of tools and materials are most suitable, and so on.

I have very little experience with anything like this and in the past I've tried to learn more about the basics but find myself getting confused by speed controllers and battery ratings and so on. If possible, a simple explanation of all this would be very useful. Thanks in advance!

Hey there, welcome to the forum!

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After a brief bit of research I've been told that beetleweight is the best category for a beginner to get into. Supposedly antweights are too difficult to meet the low weight limit, featherweights have a really high skill ceiling, and heavyweights are just too expensive.

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Beetleweights are a good class to start off in but you could argue that Featherweights are just as easy. You can easily plough in as much money into a Featherweight as into a Heavyweight depending on what you want in it. I am not sure about the skill thing though... how do you mean?

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What advice would you be able to give me? I'd like to know where I can purchase parts, what sorts of tools and materials are most suitable, and so on.

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I would begin by reading up on the build threads in the various weight category forums and the build diary forum itself, they are a good repository of what is being used in the various classes. For a Beetleweight, I find a good Dremel with various attachments does me fine. Companies like DirectPlastics.co.uk supply my materials for building with and Hobbyking.com is where I get most of my RC parts from these days for my Feather and Beetleweight.

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I have very little experience with anything like this and in the past I've tried to learn more about the basics but find myself getting confused by speed controllers and battery ratings and so on. If possible, a simple explanation of all this would be very useful.

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Do you mean things like the ratings of batteries and so on and mixing?

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Originally Posted by Ocracoke

I am not sure about the skill thing though... how do you mean?

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Pretty much the cost thing you mentioned, with many good featherweights costing a large amount. I've been told a good beetleweight is much cheaper to build than a good featherweight, and no more difficult. I worded that a bit badly!

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Originally Posted by Ocracoke

For a Beetleweight, I find a good Dremel with various attachments does me fine.

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What's a Dremel?

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Originally Posted by Ocracoke

Do you mean things like the ratings of batteries and so on and mixing?

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Yeah, those and speed controllers really boggle my mind. The milliamps, the S numbers and C numbers all confuse me with the batteries. I'm also not entirely sure what size motors and batteries and so on would be ideal for a beetleweight, and which would go together. I have very little engineering or electronics experience.

From my experience, a half good featherweight need not cost the Earth.My featherweight cost me about £250-£300ish in its current form and was able to stand up to a spinner. Admittedly, Beetleweights are cheaper - the one I am building at the moment hasn't cost me north of £100 so far.

Dremel - I use this one, hasn't let me down yet.

Batteries (I've only just learnt this as well so I could well be wrong here) - So take a battery that has a rating of 1800 milliamps and is labelled "3S1P" and has a constant discharge of 30C and a burst rating of 40C. The 3S1P thing relates to how many cells there are in the battery wired in series (S) and parallel (P).

For a Lithium Polymer battery (LiPo), each cell has a nominal voltage of 3.7v, so this battery has a total voltage of 11.1v (3S x 3.7v). For a Lithium Iron Phosphate battery (LiFe), it is 9.9v total (3S x 3.3v).

The C rating is a multiplier to the amperage of the battery so in this case, the battery can deliver a constant 30 x 1.8amps and a burst of 40 x 1.8amps.

As I say, read through the build diaries for what folks are commonly using in their robots. I am fairly sure the choice I made with my Beetleweight may need revising in the future.

Thanks very much, that's definitely cleared a lot up! Time to do more research...

I've had a bit of a play around with ideas in my head, and I reckon a strong rambot or wedge is probably a good place to start. Are these basic parts suitable for a beetleweight? I've done a bit of reading and think I've got things right. Correct me if I haven't!

Battery: https://hobbyking.com/en_us/turnigy-...flb32003s.html
Motors (x2? or is 4 wheels reasonable for beetleweight?): https://hobbyking.com/en_us/turnigy-...ner-motor.html
Speed controller (same number as motors?): https://hobbyking.com/en_us/turnigy-...-bec-besc.html

For armour and wedges and so on I've read that cutting boards can be a cheap source of strong plastics to start with, what thickness am I looking for, and how much should it weigh?

Greetings! I pretty much agree with what Ocracoke on everything he says. As for your motor selection for wheel drive, those are brushless dc motors used for quadcopters and are not optimised for robot drive. I am however using a variant of those motors on my bot, but i am using a gearbox in between motor and wheel. That gearbox comes from a different motor and was a little bit difficult attach.

as for your speed controller, again those are optimised for quadcopters and planes and will only allow the motor to spin in one direction. You will have to reprogram it to get bi directional motor control and im unsure if it is possible to repogram those (I am happy to be proven wrong on that!). If you wish to stay on the brushless motor path then I would recommend something like the Afro 12A esc (these will have to be reprogrammed using an usb programming tool) :

https://hobbyking.com/en_us/afro-12a...-firmware.html

or these:

https://hobbyking.com/en_us/multista...2a-0-lite.html (you will need a voltage regulator for your rc receiver if you use 3s batteries or above)
you can reprogram them with this:
https://hobbyking.com/en_us/multista...gram-card.html

You will need a gearbox from a 25GA 12V motor from the 500rpm varient:
https://www.ebay.co.uk/itm/12V-DC-60...53.m2749.l2649

OR

you can go the brushed DC motor route, get the 1000rpm varients from the like above, and avoid butchering the gearboxes and use brushed motor controllers like these:
https://www.vexrobotics.com/276-2193.html

sabretooths are pretty common aswell but i do not know what varient people use.

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sabretooths are pretty common aswell but i do not know what varient people use.

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Shu! (my Beetleweight) uses a 2x5A variant of the Sabretooth but tbh, if I was doing it again, I'd go for a 2x12A. The 2x5A is fine don't get me wrong but it does rather limit you to what sort of batteries you can have in it.