Hi,
am not 100% sure this post is in the right place so feel free to move it.
I am having a little problem with my 2WD robot when its sitting on my table without the wheels on the ground everything runs great but when I put it on the ground after a couple of seconds the L led on my arduino flashes 3 time in a row and the code resets, this can happen at random times and I cant work out what is causing it.
Any help would be great.
Thanks
Motor stall current too high causing voltage droop?
How are the motors connected and powered?
The Motors are powered from the arduino, which is running of 9v battery.
As long as I don't have any weight on the motors the system runs great, its just when I put some weight on the motors the arduino rests every couple of minutes with the L led on the board flashing.
Any help would be great
The Motors are powered from the arduino, which is running of 9v battery.
That's still too vague.
Are they running from the 5V? from Vin? How powerful are the motors? What's the specs for them? What kind of 9V battery? Are you using an H-bridge? Please give us information.
Any help would be great
Here is your help: Stop using a 9 volt battery. It is a weak battery for what you are doing. As soon as higher current is demanded... the voltage drop so low that the reset circuit kicks in. Go buy a cheap 9.6V RC Battery back and see if you get better results.
pwillard:
Go buy a cheap 9.6V RC Battery back
Hm, I might try that too.... with the ~3-4v drop thru a MotoMama's 298, 9.6 to give 6 for my motors sounds good... There be an RC shop near home so will pop in tomorrow.
Do you have any brand names?- don't want a championship quality one!
Jim
Usually one can tell from the price... Don't Buy any that require Krugerrands and I wouldn't buy any that were 'bargain' either as one usually gets what one pays for.
Or another thought would be to inquire the size of 'vehicle' it was made for... might get an answer you can use.
Doc
Docedison:
Don't Buy any that require Krugerrands
Good idea Doc- as it happens I'm fresh out of those right now!
I saw some pix of batteries when I Googled last night- one said it was 9 x 8 x 1.5 and I'm kinda hoping that's centimetres not inches but it didn't say!
Yeah, Hard to say except by the AH rating, D cells would fill that area and C cells would be a fair to good fit for the metric... 1.5 cm = .59"?, AA sized batteries at 800 -1200 mAH, inches I think and about 4 - 6 AH capacity... unless it's a Li-Po cell... Inches I think all in all... U?
Doc
It's this guy here Doc
But there are 2 RC shops within 10 minutes of home so I'll go and have a look at what they have on offer.
If 2 AH is good for you then go with it... what voltage do you need on your motors? If you could really drive them with 6V ea and a dc to dc converter you could get 6V at 3200 ma for an several hours of intermittent 2 - 4 meters movement or about 40 45 mins to dead battery (9.6/6) X 2A = 3.2 AH (or just about 2000 mAH) and you could get as much as 3A for 30 35 mins continuous duty, more if the the duty cycle is lower, probably not more than 50% though... Hope that helps and yes there are several switchers that will do 3A easily @ 1V max IO Differential but by that time the batteries would have been long dead... Remember the ratio of Vin/Vout X battery capacity in AH will give you the switcher output current available at full battery load... For a Buck bode and for a Boost it is similar but reverse the voltages Vload/Vbat X BATah X eff - 100%... I think, it is rather late for me nearly one in the morning...
Doc
Doc it's Sparkfun's magician which has 2x 6V motors. I'm a bit confused by their line "No Load Current:190mA(max.250mA)" which I take to mean that the max current when moving would be 250mA, although they do take 1A each at the stall.
So 2AH at 2x250ma = .5A would give us 4 hours. And this is for a toy robot right now, so running is more likely to be measured in minutes. One thing is for sure, the 4xAA = 6V battery pack it comes with does not drive the motors at all well, since half of those are soaked up by the Voltage Sponge inside my MotoMama's 298!
But I'm thinking a decent battery such as these 9.6V RC ones would be a good investment for more serious use on other projects as we progress.
(We better let the OP have his thread back now?)