Build Log | Caractacus - Any Tips?

[Ocracoke]

Firstly, I know the robot must have an LED on show when its on but I'm curious to see what some of you guys have done for yours?

For my Middleweight, I wire two LEDs in series directly into the main power wiring, each with with a 24v resistor in them so that each only uses 13.2v (from my 8S LiFe setup).

Secondly, Where abouts have you guys put your removable link? I know it needs to be able to be put in and pulled out with the robots top on (giggidy ), but I'm worried about it being pulled out mid battle.

I put mine on the top of my Middleweight, works fine though I have a short loop and some raised side armour to prevent robots directly attacking it. On my featherweight, I put it on the rear, at the top of the robot so whilst you couldn't directly attack it, it would get damaged if flipped on its back.

[willcaddy]

UPDATE: Push bot and same safety questions xD

Hello everyone

Unfortunately due to not being able to get a suitable speed controller in time I have decided to just make a push bot for the Cheltenham Extreme Robots to get a bit of experience and know what to expect for the next one. I do have some ridiculous ideas in mind though for decoration so watch this space xD

Just a few questions about safety. Firstly, I know the robot must have an LED on show when its on but I'm curious to see what some of you guys have done for yours? It's running off a 6s LiPo so regular LEDs would just fry but I saw in a YouTube video that Angus (now part of Makers Muse) used a connector and plugged it onto the Spektrum receiver with a resistor in line. I'm not really sure if this is a good solution or if there is a simpler one out there?

Secondly, Where abouts have you guys put your removable link? I know it needs to be able to be put in and pulled out with the robots top on (giggidy ), but I'm worried about it being pulled out mid battle. Having said that the loop on mine is rather long so is this just as simple as making it shorter? lol Would love your feedback Its going to be a fairly boxy robot because I plan on using the base and top panel again in the final axe robot so i was thinking of maybe putting it in the same place as Crabsolutely Clawful on the back wall of the robot?

Again any suggestions is most welcome and thanks a lot!

Will

[willcaddy]

About Speed controller, a BB80 may be your best bet now as Rory has stopped making the single channel feathertwos, and getting a duel version to run the hammer is a waste.

Sorry to be a pain! but do you have a link, I am struggling to find the controller you recommended

Thanks again

[willcaddy]

Thank you for the advice xD i think i will have a play tonight

And i was actually thinking of using the dual FeatherTwos for drive and switch out the BotBitz ones and re-purpose them for the axe. What do you think? I shall also look at the one you recommended thanks!

[Maxamuslead]

about the Head styles, they each have benefits. a point delivers the energy to a single point allowing you to make holes in materials but will wear quicker than other styles. a bladed axe (like Terrorhurts) has a smaller point to deliver energy to and will wear better than a point but it will not make holes. A hammerhead will wear the best but will deliver the energy to the larger area. TBH design something that looks cool or fits the theme of the bot (for me a hammerhead)

About Speed controller, a BB80 may be your best bet now as Rory has stopped making the single channel feathertwos, and getting a duel version to run the hammer is a waste.

[willcaddy]

Nearing completion xD

Hello everyone!

The robot is really coming along now and with loads of great advice from Roboteernat its finally nearing completion xD

Just a few questions remain which i would love to get all of your input's on!

Firstly I have read that Hardox 450/500 is the go to for a hard wearing axe head so I would like to use that but I just wanted to get your opinions on what design i should use? Is a hatchet style blade beneficial verses a pick axe style blade? I would have thought a smaller point would pierce better but I see a lot of robots going for a wider blade. Your thoughts?

Also along that train of thought, Is there anything i should be aware off when using something like Fusion 360 to design the blade and export it for cutting? (also any recommendations on where to go to get it cut? xD)

The other thing is I went with the BotBitz 85A ESCs and I found out from Roboteernat that the original ESC these are based off of has been discontinued. I hear the FeatherTwo's from Rory are pretty darn good so i was pondering switching the ESCs out for a FeatherTwo and using the one BotBitz to drive the axe motor.

Again any thoughts/recommendations on that idea and other brands of ESC?

I will post a link when i upload the latest video of what im doing too if you guys are interested

Thanks in advance!

Will

[PaulusSmallus]

You are using a brushed motor for the axe, so you can either use an ESC for a brushed motor or use an ESC for a brushless motor and change the firmware so you can use it in a brushed mode.

[willcaddy]

Thanks a lot You have been awesome

Can i just ask one more thing, did you use a brushless or a brushed scooter motor? I don't mind getting a 85A ESC of either type but just wanted to make sure which was best for the axe xD

Thanks again!

[Roboteernat]

I understand.

I had no feedback from the motor position, so stick forward is drive motor forward, back, drive motor back.
The only thing stoppuing it from going further was the chassis/floor.

a video of it running is on the build log: http://www.fightingrobots.co.uk/thre...ld-of-fw/page8 first post on page 8.

Im using a servo tester to control the motor ESC so i didnt have ti wire in the TX.

EDIT: just seen your edit and that you found the vid

[willcaddy]

Glad your recovering

My axe is run from a 150w? scooter motor through a 2 stage chain gearbox giving 5:1 ratio, so not powerful, however it was rnning from a 30 amp electronize esc - as i didnt have a spare TZ85a esc.

It was stalling allot during my time at ER 3 fights, and didnt suffer, nor did the ESC get warm.
thats my insight into it if its any help.

Thanks a lot for the reply! Was very helpful Just one quick question, did you wire it up the same as a drive motor (forward on the stick changes speed) or did you do like a servo type setup (stick position is the same as axe position)? (Hope that makes sense!)

Thanks again

EDIT: Just found your test video on you forum post lol it looks like you are doing the former xD but if you could confirm would be much appreciated!

[Roboteernat]

Glad your recovering

My axe is run from a 150w? scooter motor through a 2 stage chain gearbox giving 5:1 ratio, so not powerful, however it was rnning from a 30 amp electronize esc - as i didnt have a spare TZ85a esc.

It was stalling allot during my time at ER 3 fights, and didnt suffer, nor did the ESC get warm.
thats my insight into it if its any help.

[willcaddy]

Thanks Everyone! and a question about the axe motor ESC?

Hello again everyone

Sorry for the really long update on this build. I have had a carpel tunnel operation which has left me unable to do a lot on the robot but it is getting better!

I just have a question about the ESC for the axe. If I'm using something like a 300w scooter motor, the first question is probably obvious lol but what ESC would you recommend based on the motor is probably going to do a fair amount of stalling in a battle?

Second, would it be a case of wiring it up the same as the drive motors or is this liable to snap the chain if you go to mad with it? Is a set up similar to a servo what you need? and if so, what would you need to do to add that functionality?

I hope that all makes sense!

Once again a big thank you to you all for taking the time to help me out! I have never known such a wonderful community

All the best

Will

[qbnut]

It is strictly in the FRA rules but I think that EOs bend them on this one, especially in the age of spinners. A chunk hit off in spinner blow is in my opinion likely to do more damage than an axe head falling off or being thrown.

Battleaxe had a chain tether at Insomnia last year and this was accepted in tech check though it broke in the 722 battle when the head came off anyway :/ It's now on a steel cable tether. Broadax on the other hand is one-piece Hardox so I don't believe it will be required depending on the EOs discretion. Though if in any doubt about the robustness and safety I would add a tether. You are right as far as I know the last Hatchet revision wth the one-piece also did not carry a tether.

It might be the case of still being needed for arenas without a roof I guess.

[Maxamuslead]

I think that's the main reason. It's more for axe heads that are bolted onto arms where the chances of the bolts shearing is reasonable, but on Onyx the axe head is welded on, so it's a bit redundant, but dems the rules

Sorry for hijack but is this required for any axe head evan if the shaft and head are one of the same E.g. Hatchet's ?

[RogueTwoRobots]

Sorry, just saw your edit.

The boss is the protruding cylindrical part that comes on a lot of sprockets. It's a good wall thickness on the 40T sprocket which made drilling and tapping for grub screws nice and straightforward

_20180406_180541.JPG

The tether is in the rules so that if the axe head becomes separated from the arm, it doesn't go flying off, potentially breaching the net roofing of some live arenas and into the crowd. At least, I think that's the main reason. It's more for axe heads that are bolted onto arms where the chances of the bolts shearing is reasonable, but on Onyx the axe head is welded on, so it's a bit redundant, but dems the rules