Ignore this :)
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Ignore this :)
The fuse is there to prevent lipo fires, not protect the electronics. The fuse rating is chosen to be somewhere over the maximum current likely to be drawn by all the ESCs simultaneously but less than the maximum current capacity of the Lipo pack.
The blade car fuses are a bit under rated if your bot has an active weapon, midi size fuses are what many builders use.
sorry i tried to remove my post but didnt see it come up, i didnt think anyone would read it before i got to work, looks like you did :)
ignore my post, i read rules 7.8.1 :D
Okay... now I'm a little confused again... so would it be more logical to get a 100 amp fuse or a 90 amp fuse by that logic? Considering that the battery in question gives out 94.5 amps.
It depends on whether that 94.5A is the continuous or the peak rating. Most packs state both and the peak is usually between 1.5 and two times the continuous rate (if the peak rating is not much more than the continuous rate, its a very good sign of a low quality pack). If that 94.5A is the peak rating, I would go for a lower rated fuse, about half way between the continuous and maximum rates.
Well the math I went off of was the calculation from the FRA rules and regs.
The battery is a 35C series, and it does 2700 mAh, which is specified on the front of the battery.
Which means, by going off of the multiplication of that, 35 x 2700 = 94500. Which means by logic, that brings it to 94.5 amps.
It's Burst rating is 45C according to the hobbyking website. So if I make it 45 x 2700 = 121500. So that in logic makes it 121.5 amps.
Sp somewhere in between those two? I've looked at Halfords and their 110 amp fuse is a strip fuse, which doesn't seem to be the right kind of fuse... which is here.
Their 100 amp fuse however looks a little something like this.
And Maplin doesn't seem to hold any that's suitable for that kind of amperage from what I've seen.
All this math is making my head spin... why did I flunk my systems and control class...
The fuse is mostly to stop the electronics pulling too much from the lipo, lipo gets hot and then catches fire. So the rules say you must have a fuse for the maximum the lipo can supply, but in reality you won't get near that with a pair of drill motors. They pull about 30 amps a pair tops. So in that case you could put a 30 amp fuse in and roberts ya mothers brother. If you have weapon motors as well, add the current to 30 ish for the drive and buy for that. It's as complicated as you make it.
David, that's made things a lot more easier. I can easily find fuses as such in Halfords. And if not in Halfords, then I'll just look to ebay. Quick question... yes, I know, another one, but I always just want to make sure. One battery leading into a ESC controlling the two drive motors, will I need two fuses or just the one for that?
So that'd make my shopping list...
Shorter M6 bolts, as the ones I have won't fit the drive motor mounts.
2/3 fuse holders, one for the drive, one for weaponry.
2 30 amp fuses plus spares
24v strip LED lights
And a pair of wheels.
Once that's all done, I can get on to getting on with the weapon system.
Back at it again with the LEDs... Would connecting say... a couple of these just after the 30 amp fuse work or will the bulb just blow straight away? And will I need some sort of mounting board to go along with them?
My understanding of the rules is that you need one fuse and it sits between the battery and ESC(s). So following the wire along you have battery - fuse - Power LED - ESC(s).
Yeah, I figured that out as well, but all I'm wanting to know is that if the LEDs I linked in my previous post is suitable for the task at hand, or if there's any out there that do the job better and if so, I'd love to know what it'd be.Quote:
Originally Posted by McMad
So I measured the radius of drive motor axle to floor, and it's about roughly 5 and 1/2 to 6 cm off the floor, which means best bet for wheels is possibly a 120mm-125mm wheel maybe? And seeming as that's the case, would this be a suitable wheel to go for here?
If not, what are some other suitable wheels at that size, considering that I don't have a lot of space to work with, and I'm wishing to make it a direct drive from axle to wheel.
I don;t think those LED's are suitable on their own, they'd need a resistor to protect them as they can only take a few volts. Someone with a better understanding of the voltages can suggest a value.
You will need a resistor to reduce the current correctly, something like a 560 Ω Resistor will be suitable, if you go this route I have several am happy to stick in an envelope for you.
Otherwise if you want plug and play...
Heres some someone has pre made http://r.ebay.com/DBUsuv for single led a nice 10mm will be fine.
Otherwise look for '12 v LED'
If you do want an LED with resistor, I can see what I have got and send one to you too...
Just get some 12V LED strip on eBay. It comes with a sticky backing for easy adhesion and you can just wire them up in series to drop the voltage to them. I run my robots on 5S/6S with series linked LEDs and they're absolutely fine. No resistors or anything to worry about. They're also a lot brighter and more visible than normal LED bulbs.
I still have the offer for the LED strip if you would like a length? 12v or 24v rated. (in white tho)
Hi hi, sorry for the late reply.
I managed to get the fuses sorted out, went down to halfords and bought a set of 30 amp mini blade fuses, along with holders. Means more space for components at least.
Thank you for the insight Jamie, at least I don't have to mess around with resistors, which is one less thing to buy.
And Nat, I'll give you a nudge a little later to see if I can buy a couple of strips from you. Have to consult with my mother before hand, so she knows what I'm spending my money on and such haha. Which means I'm interested but I'll have to either contact you later on today or tomorrow.
Alright... more than likely the last time I'll bother this particular thread, as the item in question is castors... what'd be a decent castor for featherweights? And if so, would it be available with M6 sized holes too for convenience sake?
I don't know of any featherweights that run castors, even heavyweights don't tend to run them. They're often too weak for robot combat so most people either just let the leading edge of the robot/chassis run on the floor, or mount a low-friction material (eg. Nylon) skid plate on the underside of the robot.
Ah, fair enough, fair enough. I'll try to get maybe some kind of skid plate instead then. Might end up being part of a plastic bottle or some cut up aluminium soda cans, and try and smooth some of them out. If that doesn't work, I'll have to try and think of something else. Thank you for the information Jamie.
The Honey Badger does use a castor on the front and previously did so on the rear when the wheels were located in the middle. Strictly speaking the rebuilt version doesn't need it., it has enough force to move on its HDPE base with the motors driving it along but I find it helps make it a little more controllable. I use castor balls in mine (http://www.ebay.co.uk/itm/301529661473) rather than a wheel to help with ground clearance.Quote:
I don't know of any featherweights that run castors [...]
So, just got my second sheet of HDPE, and to top it all off, Nat gave me a pair of light strips that I can pretty much place where I wish onto the robot. So as soon as the weather's clear again, I can cut out some wheels for the drive, wire it all up and test it all out. Special thanks goes out to Nat for the superb delivery, and like I said, if my motor mounts don't cut the mustard, I'll definitely be contacting him to see if I can get some motor mounts from him. :)
Well, I posted this on my build diary, but I'm going to put this question out on here just in case, because I don't want to burn through an ESC because of a stupid mistake. So here's my diagram, so to speak.
Attachment 7025
Is this the correct wiring? Or have I got things wrong? The black box with the line through it is the fuse, just for the sake of time haha.
Also, I know I got some of the markings unfinished, just... kinda hurried with it, my apologies.
Well I guess you can ignore the last post, got it answered in the Build Diary, so there's that haha.
Insert loud sighing noises here.
So... I tried using EC3 connectors... and I keep spilling the solder out over the edge and down the sides of the little connector things, which means I can't get them into the housing... so I'm thinking of either getting some EC5 connectors from Hobbyking or take a train to Dodworth and go to Fast-Lad to get some. And get a couple more metres of 14awg wire too. Any recommendations on wires? Or am I better off getting more Turnigy 14awg wires?
Unless there's a better way of doing it.
Oh yeah, I've also learnt how to tin wires properly, so that's something I'm somewhat proud of.
Same thing happens with the EC5s depending on what gauge of wire you use. The trick is getting just enough solder in the cup to form a good bond but not spill over. I'm still trying to find that balance :)
What I do is take a small flat file and just file down the solder (it files away quite quickly) until the connector fits in the housing/opposite connection. It's a bit time consuming is the only thing, so can get monotonous when you're soldering several connectors.
The XT range of connectors don't suffer from the solder overflow.
I've had the same problem with the EC5s. If there is not too much solder spilled down the side you can get them into the housing with a bit or force when they are still hot from soldering. The heat makes the plastic just pliable enough for them to go in. Careful not to burn your fingers and good luck if you ever want to get them back out.
Failing that, as Jamie says, a quick file to remove the excess will usually get them in.
Well... I think that I should honestly get started on the batteries. Only problem is I don't think I have a charging lead that can connect to EC5 (yes, turns out I have EC5s, not EC3s, I'm bloody wally...) connectors, so I think I may have to fashion one out of one of the charging leads... is this a good idea or is it a relatively bad one?
Also, is housing LiPo batteries in an old ASDA plastic food box a good thing to do cushioned in with packing foam or is it a relatively sketchy thing to do?
Any advice here'd be greatly appreciated.
PS, watching the 20 man rumble of I61, and I swear if it wasn't Robochallenge, I'd have thought someone'd bring in tables, ladders and chairs into the ring... wrestling jokes ahoooooy...
I would think it was OK, it is what I've done with my LiFePO4 batteries (though I am open to being wrong here if that isn't a thing to do). I've screwed down the battery box to the chassis board and then screwed the lid to the box, lining the box with material on the base and the lid and having the same material supporting the box on the overhang from the screws.Quote:
Also, is housing LiPo batteries in an old ASDA plastic food box a good thing to do cushioned in with packing foam or is it a relatively sketchy thing to do?
Thanks Michael, but now I got more issues... always something with this damn robot, haha...
Got three that immediately spring into the fray and are the most important, especially as 5 minutes ago I just dry tested it on top of the drill set I've been using to drill holes into the bot haha.
1) How the hell does one make and mount wheels to drill motors? The ones I made, the counter helix screws keep unscrewing themselves and, therefore, the "wheels" keep falling off.
2) I got the damn thing to move the motors, which makes me smile... the only problem is that they spin in opposite directions. I move the stick forward, the right motor moves forward, but the left one moves backwards. How do I get them to spin the same direction?
3) Once I do that, how do I get the bloody thing to steer? Do I need to mix the signal in some way? And if so, how?
I know it's a very shoddy representation, but this is what I'm working with...
Attachment 7230
Any and all help would be greatly appreciated.
To address your questions directly:
1) I can't really answer this one, I don't use drill motors per se (I use a pair of Gimson motors with matching hubs). I might suggest either some threadlock fluid or a nyloc nut though. I can't visualise how you've got them mounted. I definitely know the Featherweight version of Luna-Tic uses drill motors in this fashion though, might be worth asking cjsowry.
2) I'd swap the + and - around on the motor going backwards. I was forever having this issue with The Honey Badger after a dry build so I use a pair of matching connectors on both wires to the motor. If I find it is going backwards, I can swap the connectors over. I have a feeling you may need to swap them at the motor terminal though as you use EC5 connectors (so de-solder and resolder them). There is also the very hacky move of cutting the wires in the middle and then soldering across (so the wire from the connector on the left would be soldered to the wire going to the motor on the right for example).
3) I don't believe it is achievable in the setup you have at the moment. A channel can only really have three states; Up/Stop/Down. As you are sharing the signal between two speed controllers, they'll always either both go forwards or backwards. You need to have the speed controllers on separate channels.
Early attempts at The Honey Badger came across this problem. I ended up using the side to side channels instead of the up/down channels (as one would stick since it was for helicopters) until I found a controller that had sprung up/down sticks on both sides (so tank controls).
I think some controllers do support channel mixing as I looked this up when designing my Beetleweight but otherwise, it would be a Sabretooth or similar controller (which I know you've already tried) that you'd need. I must confess though, channel mixing is something I am pretty new to myself so I would defer this to someone more experienced.
1) There is a couple of methods, a popular one to use something akin to thisAttachment 7231just slid in the gearbox and bolt down the holding block. simple but effective. (also add a block to hold the motor stable and it stops too much force being applied to the gearbox motor join point)Quote:
Originally Posted by Outlaw
2) Check the RX/TX. swaping the cable does work but getting to know your Tx/Rx system will help as some drill gearboxes run faster in one direction so knowing to adjust trim and limits will help there.
3) Again check your Rx/Tx. If it has mixing capability then you can mix the to drive channels onto one stick so when you push forward you go forwards and etc
So I checked, and by the looks of things, the r/c doesn't have any mixing capabilities... well there goes that idea down the bleeding drain...
So, if anyone has any suggestions for a Radio controller and receiver combo within that can mix at a decent price, then please let me know, and I'd really appreciate it.
Also, tested to see if the lights work, and I think they require too much power for what I need from them, so I'm going to have to give roboteernat a nudge for them, haha.
A product like this might help?
http://www.mtroniks.net/prod/RC-Acce.../Tankmixer.htm
If @Lowndsy mixer that he linked doesn't get what you want or you fancy not using a external mixer, you could get this RC kit.Quote:
Originally Posted by Outlaw
https://hobbyking.com/en_us/turnigy-...er-mode-1.html
which i have got. I yet to use it in combat, but it is easy to mix and with some hacking able to use 8 channels (IIRC) rather then 6.
And to add a third option into the mix, The Honey Badger doesn't use any mixing at all. I've got a transmitter that has has tank like controls on both sides (a bit like Panic Attack's original transmitter when you see it) though it does make going in a straight line a bit interesting if you don't push them both equally.
My transmitter is a Carson Reflex Stick 2 but they are jolly expensive - £95 on eBay. I'd go with Maxamuslead's or lowndsy's advice on this one if I was starting over again ;)
I was originally going to use the tank mixer with a pistol grip remote to make it as hard to control and unpredictable as possible - sort of the Donald Trump approach.
Then I got a cheap DX6i and figured it might be nice to have some sort of control...
I'm pretty sure most TXs have built in tank mixing now, my transmitter was pretty cheap and was still able to do it.
Well if I do go down the Nyloc nut route with the wheels, what'd be the best way of getting the nut into the HDPE? And when I measured the drill axle, I think it needs to be an M8 or M10 nut. Would this happen to be alright?
Also, for clarification, I managed to get the controller that Maxamuslead put up. I'll just use the other controller for the weapon and give my friend something to use if we're both out there. :P