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also a note about the electronize controllers. I have run them for over a year now, I use two 15amp CPU ones in Alpha. Anybody whos seen alpha run knows how much of a thrashing the controllers get. But they have never let me down, and only had to change one relay (im not using the external Mod). Failsafes have also never let me down.
OK, they may not be the most responsive, but most drivers should be able to cope with it.
We all tend to stick up for our chosen solutions, and from what you have heard about electronize its understandable you were amazed at our lack of decent controllers, but just to put one or two things right.
1st, they DO failsafe, [EDIT]
They have mixers, if you buy one and attach it. The difference being we can choose our mixers, and still work out cheaper. IBCs are built in and they raise the price of the whole unit.
The electonize stick sometimes, but thats nothing a relay upgrade cant cure. This occurs when running them above their rated current, buy relays capable of higher and they are fine (mental not, re-read that James, you blew your relay!)
Crappy control? not sure about that one. If you want brakes, use worm gears. I for one like the way electronize respond, but, I havent tried the IBCs, they may have better control.... I wont know til I have a go.
As I say, not dissing the IBC, just sticking up for electronize, they get a lot of bad comments when they are really good solutions when used as designed.
Useful info on Electronize Controllers collated here from another thread.
FRA Forum Admin
The IBC is a little more expensive but the controller is fitted out with all the cables and I have had the controller running at over 70Amps. I have been using mainly drill motors and gear boxs so the electronic braking helps, to stop the robot on the spot and turn around. Anyway I have been happy using the IBC with no problems.
Is there anyone besides me who get flashbacks from that old discussion about 4QD and RoboteQ (as the discussion about Eleztronize and the IBC is quite similar)?
Jason- Electronizes also come fitted with wires and fuses atached.
And as James said if you need precise breaking-use worm gears. I could stop Turbine 3 straigh away, and im sure James gets the same affect with trinity.
Regards
Dave moulds
Equally, worm gears are, althought nice and simple and compact, one of the most inefficient methods of power transmition. It is, like everything in life, and balance. :)
But for 50:1 reduction under £20.......
noted Eddy, its not the most efficient solution.
Horses for courses I suppose.
Have asked this elsewhere, but as Admin have very kindly started this thread Ill ask it again.
Mixing.....
the mixer I currently use is a Ripmax V-tail. its designed for RC aircraft. the problem is it only gives 60% spin rate as it leaves room for the aircraft to stipp have some movements in the elavators (the throttle on the robots)
Is there a better mixer, preferably one that is compatable with a simple piezo gyro, and does anyone know if the IBC mixer has 100% spin rate on its mixer or does it cut to 60% for some reason.
(trinity........... humm..... forgot all about her recently)
that should be still not stipp
the ibc has a 100% mixer.
ive never tested it out myself but i believe my GWS v-tail mixer is 100%. ive tested it out with and without it in and it appears to have full spin rate.
we had this problem with alpha. I currently use a GWS (i think, the little black heat-shrinked ones) and they dont appear to reduce the throttle. Gyros and electronize dont mix! they just arent quick enough to respond, i tried ours in alpha and it sat there shaking!
The electronise can run gyros I tried one in thuggernought before and it worked ok, if you get the shakes it is usually a sign of the gain being set to high on the gyro.
Basic Gyros can restrict the ability of the bot to turn however. As for a mixer I use the IMX-1 from robotlogic.com its very good.
Ive had no probs with the GWS mixer. Its only about £10 iirc. Small and wrapped in heat-shrink as Alan said.
Eddy
The RC in RC out mixer from Technbots has served KatRip well. I didnt notice any lack of spin with and without the mixer.
But in all honesty, i didnt know some mixers resrict the speed of a robot spinning. I see your point now as they are built for aircaft. Hmm something for people to look into maybe. But i thought it just mixes the channel, not restrict them.
Mr Stu
The IBC also has a dead band for those who would rather have the robot turn more slowly instead of having to over correct yourself when you jam the stick a little too far.
Dont most, Evan all Speedos have a small amount of deadband?
Regards
Dave moulds
P.s. Im not good with electronics so let me off for silly quetions :)
Dave, it is essential to have a small deadband on speedos, some may have too much (standard 4QDs) and some are adjustable (Vantec & Roboteq). The wider the deadband the less stick movement you have left to control the power. Too small a deadband and the robot may creep due to tolerances in the transmitter / receiver and speedo. Effectively, within the deadband, stick movement has no affect on the power to the motor. Not sure I understand what Aaron is referring to.
More advanced speedos also allow you to adjust the relationship between stick position and power to the motor. Most basic speedos are a linear response. Again, more advanced speedos allow an exponential to logarithmic relationship.
Paul
I think he Aaron is trying to point out that there are two settings for the size of the deadband.
Joe Townsend
Ah gotchya, Thanks for clearing that up for me Paul.
Regards
Dave moulds
If anyone with a mind for code (not me, causes me headaches and a desire to put my foot through the monitor) and feels like playing with the idea of a exponential to log relationship for an IBC (seeing as the source code is available. Thats a point- will see if we can put it up on fw.org) then that would be great. I tries doing such a thing last year, but, as i mentioned, I got too stressed to easily. Electrons are a load of gits, steel is friendly :-)
Just looking at the IBC and has anyone else noticed it says its got reverse battery protection. Judging by it circuit diagram you will get alot of smoke if you try that. Also (I may be wrong) but 50A continuous? Will need a very large fan. But as they are usually not used for more than 5 minutes and then never at full current for that long they should be ok.
Sorry but I dont know how to program those and not looked at the code, but i didnt think it would be too hard. All you would have to do is find the code that updates the PWM output and apply a log or exp function just before it.
*goes back to the bench to figure out why his dual speed controller doesnt work yet*
If Im honest, Ive never been very happy about putting anything much more that 20A through a TO-220 case. They just dont look up to it :-). Mark- I will be modding my IBC with a slightly larger, finned heatsink, and a little fan. Im a bit of a nut about things running cool, especially batts, considering the amount Ive just forked out for mine :s
The IBC does infact have Polarity protection. We had a competitor running at Robowars 2003, KO, 4 x 12v drills on 24v with a possibility of drawing over 200amps on a moderately large drain and it only got the IBC warm, that was with out a fan on the heat sink, and Tim was making KO push a fair bit, I know, I was able to get a beautiful view of two sides of the arena :).
On both of our IBC that my team owns, we have small 40mm PC fans on them to have that extra bit of protection, expecially when running T2M with its 340watt winch motors (When you see your team mate who is around 80kg sitting on top of a feather weight doing over 5MPH in the pits doing a wheel stand on your feather weight, youll under stand why we have a fan on the IBC :proud:)
Brett was running BullDoze, a heavyweight on an IBC using wheelchair motors at 24v and it was getting fairly warm, but it with stood the punishment.
Ed, if your going to make up a finned heat sink, let me know on the prices you can get them made for, you might be able to sell them as IBC Upgrade part with fan attached :)
Will do that. If there is sufficient interest, I dont mind doing a small batch on the mill. It would only be fairly simple tho- anyone with a block of ali and a free hour (and a mill) could make one.
Its important to note that its the MOSFETs that get the abuse on the speedo, and its a rule of thumb that a reduction of 10 degrees at the junction of a semiconductor approximatelly doubles its life, and especially with people drawing 50A through those poor little to220 packages, cooling is important. For a few grams extra, a fan has got be to worth it. I have built a speed 300 motor powered fan, which really howls, and, once i stick it on my modded heatsink, should ensure long life and excellent performance- forgot to mention above that as the mosfet heats up, its on resistence increases, thus making it heat up even more- its all wasted power that could be going to your motors instead of damaging your mosfets.
Stay cool :)
Ed
Ive checked the circuit again and all I can say is if you think its got polarity protection then try it. The MOSFET are not protected (acording to there published circuit) and will generate a short across the battery. The only protection they have is before the voltage reg for the ICs. This should be made clear or someone will try it and be very dissapointed. If it does have a diode protecting it as it says it does then a diode at 100A with a 0.7V (at best) will produce 70W of heat!! Far more than you will get with just the MOSFETS and would take this power away from your motor. Again all I can say is try it but be prepared for the cost of repair.
Ive just had a look at the circuit diagram available via robotcombat.com and I agree with Mark. If there is reverse polarity protection then its done by something not shown on the circuit diagram. The same document states that theyre reverse polarity protected though, so if they do burn when you accidentally connect them the wrong way round, I would expect them to repair it free of charge.
If anyone has a link to the source code for the IBC I will take a look at it - I cant find it on robowars.org.
http://www.robowars.org/docs/ibc-docs-v0.1.pdfhttp://www.robowars.org/docs/ibc-docs-v0.1.pdf
thats all there is i think
Its only a cheap diode placed in the battery circuit, so if you do cross polarise, it will protect the main important parts of the board and only blow a small 15 diode which takes 5mins to unsolder and replace. Saves you loosing $$$ because the diode wasnt there.
You can infact short circuit the diode afew times with out it blowing, weve had one person do it a few times and they still keep working.
Instead of starting a new thread I am going to bump this one.
Has anyone here got a Scorpion XL in their featherweight and what are your experiences with them? Good and bad reviews all welcome.
One is now in Little spinner as of last weekend, but has not been to an event using it, allthough we are taking it to an event in 2 weeks just to test the drive.
We have fitted 2 heatsinks to it though, one for the mosfets and one for the voltage regulator which gets very hot with a battery voltage around 28V and using the BEC.
Still need to do some work on it as the Spectrum sometimes enters failsafe when we turn the spinner on, even with a 0.5 seconds slow turn on. I assume this is due to a combination of the BEC in the Scorpion XL and not much storage capacitance, but will look into it as there seems to be alot of noise on the 5V line.
Thanks for the info Mark. The nipper team is going to be at XFM with it?
Mark ... Are you aware of the recent mods to the XL?
http://forums.delphiforums.com/THERFL/messages?msg=2640.18http://forums.delphiforums.com/THERF...es?msg=2640.18
Thanks woody, but we should have the new versions as they work with the spectrums just not when the weapon is on, but will check the voltage regulator at the weekend.
Leo, Yes
(Message edited by big_nipper on May 24, 2007)
having spoken to Mark it sems the huge current draw of the magmotor is causing the voltage to drop suddenly from 28v to 3v for a fraction of a second. This triggers the scorpions on board failsafe.
Mark is working to fix this, and a seperate reciever battery may cure it.
This may be the same thing that was happening to Cyberon at Northampton last weekend.
All scorpions supplied through me have the updates mentioned by Woody, so should work fine with the Spektrum.
I will just use this thread instead of making a new one.
My dad is about to start making his robot and is wondering what speed controllers to use.
He is using 4, 18v drills and we were told by robot power that the scorpion XL would not handle them. Would running 2 scorpions be ok?
if not what speed controllers would be the best option?
Also my dad has just asked me what would be the most powerful drive, 4, 18v drills or 2 gold motors?
Will
Is it going to be a pushbot? Go for the Sidewinder. with 4 18V drills or 2 24V gold motors youll be thankfull you did.
Drills vs Golds - Personally Id go for golds if you can afford the cost of them, the drive train, and batteries to supply them with enough oomph.
Obviously the drills come with the whole gearbox attachment so its just a case of bolting them to a chassis, but with golds you have much more flexibility over desired speed and pushing power. One particular example that sticks in my mind is Team Mads Omega. If youve seen that in action youll know its a more-than-able pushbot (its on a 3.4:1 reduction I believe).
I think Omega also uses 15A microprocessor Electronizes for control (is that correct Alan?) so that controller or anything above in terms of rating should be sufficient to control them. The extra costs of the drive-train and motors is kinda balanced out by the possible use of low-cost speedos
I would go with the drills as the gold motors are pretty heavy, and 4 drills should be more powerfull and much easier to create 4wd/easier to get hold of and cheaper.
Will you should have noticed by now that Whirlpool can out puch DB5. So drills win, but I think that my drive is now more reliable than drill gearboxes.