Asked — Edited

12V Dc Motors?

For my upcoming project(no hints, but cardboard is a material) I need 2 12v dc motors to be run off the h-bridge in the store, which means the max motor amperage is 2.5Amps.

Size isn't big but the robot will be mid-sized. 5 pounds or so of torque per motor if possible.

If it could have a wheel that would be awesome!

Anyone who can link me to some motors will be put on the credits list for the future bot.

Thanks guys!


Upgrade to ARC Pro

ARC Pro will give you immediate updates and new features needed to unleash your robot's potential!


Consider getting a Roomba "for parts" , it will come with a couple of drive motors rated at 12volts.


Robot-doc, would they be enough?

Troy, I like the site but I priced the stuff needed and it's almost $100.

Any other sources are appreciated.


@Technopro Those will work, but 300rpm is a tad fast I would think... If you pwm down it won't have any torque left... It is a motor definitely meant for high speed.. I like motors of around 100rpm on the output shaft... A Roomba is close to that (100rpm or so) or even possible a little less...


@Technopro, No problem. I know it can be pricey.


Actually, now that I look at that one again, it is pretty slow. There are others though.

(edit our last two messages crossed)


The one that you are looking at would probably do the trick. The description mentions robots, so I would guess that it is not made just for racing cars. You wouldn't have to buy tires, anyway.


Your latest link could work, its just about trying to find a wheel.


Remember to figure the circumference of the wheel you're attaching it to. Circumference=3.14 {or pi} X diameter. The circumference is the distance traveled per revolution. Divide your revolutions per minute by 60 to get turns per second. Say for instance you have a 3" wheel and a geared motor going 120 rpm. 120/60 is 2. The circumference is 9.42. So 2 revolutions of 9.42 is 18.82" per second. Kinda zippy. Granted that the rpm rating is when not under load but you can get a better picture of how fast it may go.


ok so seeing as I'm so tired I didn't understand that what do you think is better? 300rpm with 2kg of torque or 200(152)rpm with 2.8kg of torque?


I vote for more torque and 152 or 200 rpm. That still gives an overhead for pwm to get slower. Just my opinion. Edit. I just looked at the link you had. I didnt realize the speed was already in there with the wheel size. Unless Im missing something Im coming up with over 32K mm per second. 68mm tire size X 3.14 X 152 rpm = 32455mm per sec or 1277.7559 inches per sec or 106.48 feet per sec. Im a bit tired it seems. EDIT: I slipped up and didnt realize I forgot the answer was per minute not per sec.


I checked the math Troy. The wheel diameter was 65mm. That translated to 2.559 inches, giving a circumference of about 8 inches. Turning at 152 rpm would be 1216 inches per minute, or about 20 inches per second. It would cross a good size room in about 10 to 12 seconds.


So we have it! Ill get the 200rpm motors

Got my ping sensors from china last night and inspected them. Some for roli mega, the others for my next bot.(trying hard not to spoil the surprise!)


Thought i'd post product info for anyone who finds this thread. Product Name: Mini DC Tyre Motor Assembly; Motor Model: 37GARH; Voltage:12VDC; Rated current: 1.1A; Motor No load speed: 200r/min; Motor rated speed: 152r/min; Motor rated torque:; Tyre: 6827mm(DT); Shaft:Dia 37mm Long; Motor Speed: 653.14152mm/s; driving force: 2.8รท3.25kg Total Size: 65104mm(DH); Material: Metal, rubber; Color: As picture shows; Weight: g; Package Content: 1 X DC Gear Motor + 1 X coupling + 1 X stand + 1X tire;"


@danger, thx, lol I knew that I couldnt be right on that math.


No problem. The first time I did it, I was thinking it was 20 feet per second. I told techno that it would be way too fast. Then I thought about it and had to go back and edit my post. 20 Inches per second is still a little quick for a robot but I am sure that with pwm he can get it into the right ballpark.