Starting Point

[RogueTwoRobots]

Re: Starting Point

For the voltage problem, 28.8V is the nominal voltage of having four 7.2V packs connected up (1.2V per individual cell). When a battery cell is freshly charged though, it can be up to 1.5V so multiplying that by 24 (total number of cells in four 7.2V packs) gives 36V. Even if they only charge to 1.4V each, that's still 33.6V so the chance is that it is too much for the controller.
I assume it goes back to working again if you revert to 21.6V after trying the 28.8V setup? If so, then the controller's probably got an excessive voltage cut-out circuit in it to protect the unit.

[zoll]

Re: Starting Point

Cheers for the tips, I think you are right as the batteries were fully charged. I dont think it was anything to do with current draw as it just didnt come on atall. Think I might just run it off three packs anyway seeing as thats powerfull enough to destroy the rig I made. Would HDPE or Nylon 6 be stronger then wood when the axe tries to rip the screws out as the wood just splits along the grain line, or am i going have to go straight to metal?

[typhoon_driver]

Re: Starting Point

Nylon would be able to take it if thick enough but to be honest I much prefer metal and aluminium really isn't that hard to work with. Some basic tools and you're away! I also gotta say if you're gonna have that axe swinging around I think you really should go for metal!

[zoll]

Re: Starting Point

Yeah oki think it might have to be metal then, btw before my rig destroyed it self it swang the full length axe at some fair power, made large hole in some chipboard. What thickness alliminum would you recomend and where am i looking to buy it from?

[zoll]

Re: Starting Point

Anyone any idea how to limit the return speed of return using a DX6 and victor 883 to say 20%?

[zoll]

Re: Starting Point

Sorry to still be boring you all with all my questions but I really do apprieciate all the help you give me. I've remade my little rig for my axe out of slightly stronger wood while i learn how to work with metal and ive notice the gear reduction through just the chain and sprocket that I have on it is really not enough and I some how need to gear it down further to produce more torque. How would I go about making a gear box to go this? Thanks again Matt

[psycho_fling]

Re: Starting Point

to make a gear box you would need gears instead of the chain and sprocket approach (can be done but will be quite large)

usually you would need a 2 stage reduction gear box in order to get to the desired torque or speed

any parameters we can look at as to current spec and the desired figures??

[zoll]

Re: Starting Point

Anyone know what size box section is good for making a frame and where I can get some?

[typhoon_driver]

Re: Starting Point

For a featherweight look at 10mm by 10mm or 15mm by 15mm and a mm or two thick steel box section. You can roughly calculate what weight your chassis will be by working out the weight per mm length of box section and then total it up based on how much box section you would use. For a supplier best to look locally. Look in the yellow pages for a steel or metal supplier.

and with regards to gearing your axe down, calculate the gearing that you need and then we can better advise on what would be the best method for gearing.

[zoll]

Re: Starting Point

will 10mm be thick enough sounds very thing to me?

[psycho_fling]

Re: Starting Point

id go for some of the stuff i have on offer to you that way you will make sure there will be no problems

[typhoon_driver]

Re: Starting Point

For a featherweight 15mm wide box section is fine if you go for a 2mm wall thickness, 10mm may be a bit thin yeah. If you are planning on taking on spinners then I wouldn't look to use a box section chassis but for non spinner fights it will be more than enough.

[zoll]

Re: Starting Point

Hi again not got anything really done over the last few weeks am busy with university exams... my finals but am just having a bit of a break.

Ive come to a bit of a dilema with my robot as in I want to start making it out of metal but have a few dilemas. Main dilema is that I need a welder and dont know wether to go for something like a cheap and chearful arc welder that will probably set me back £80ish pound after all gear is brought or wether to go for a DIY mig something like the clarke 90 with gear and gas would probably be around £300.

Also is a box frame the way to go or is there a better way to do it?

[psycho_fling]

Re: Starting Point

a box frame is a great cheap and easy way to learn welding etc

you can also make it all out of bulkheads, i.e sheets put together like a jigsaw puzzle then weld or bolt

might be easier to advise if you post a picture of the frame you wish to make

alex

[elobire]

Re: Starting Point

sorry to hijack your thread, but where did you find the wheels that you used for the axe? ive look everywhere and cant find ones made from metal.