Boring Brick

[mrsam]

Got my axe motor from Dave Weston last night who was kind enough to drive down to Birmingham to drop it off, however since the motor had no sprocket attatched I was planning on using an 8 tooth one I had lying around but the bore isn't large enough and I don't really have the right tools to widen it let alone drill and tap the boss for a grub screw. This puts me in a predicament as I don't have enough money to spare to get one from technobots and im not paying nearly 8 pounds from eBay for a 9 tooth sprocket which would have originally been used. So I don't suppose anybody has a spare one they don't mind parting with? Or would be kind enough to modify the existing sprocket with an 8mm bore and tapped hole?.

[mrsam]

Cheers Harry that worked a treat

[harry hills]

Put a notch on their heads with a dremel or hacksaw or something and get them out with a flat head screwdriver.

[mrsam]

As i seem to be stripping bolt heads faster than i can put them in i've had to hastily order some m6 high tensiles (up from m5), the m6 bolts that i've tapped into the baseplate have given me no problems yet the m5 for the chassis strip so easily. Does anybody have any advice for removing the stripped m5s because they've stripped their heads still inside the chassis

[mrsam]

I'll see how it handles when the mixer is all sorted and it's tested properly, and a 300 watt scooter motor

[Revsmin]

You still after a gyro for it? Looking great BTW, what axe motor you using?

[mrsam]

I've now got a mixer in the robot and it all works fine but now it won't failsafe, I've tried rebinding but it hasn't worked, any help would be great

[mrsam]

Main axe sprocket and mixer ordered today and axe motor will be with me next week courtesy of Mario and Dave Weston so expect an axe test video mid to late next week

[mrsam]

Adjusted the ESCs and gave it another drive test, seems a bit better but the batteries are going a bit flat so it's quite slow http://s921.photobucket.com/user/mrs...3a7dc.mp4.html

[mrsam]

Thank you, for the moment it's just going to GSL but hopefully I'll be able to get to some more events if I can get the time off and some way of getting there.

[Danny B]

Looking very good so far! Any idea which events you plan to bring it to?

[mrsam]

Thanks Jamie I'll give that a go, the electronize will probably be the first thing to go when I rebuild/upgrade Hatchet as they definitely aren't the eaaiest things to use

[RogueTwoRobots]

It's a common issue with robots that have their wheels at the front, they tend to be a pain to drive forwards (spinning round like that) but they reverse remarkably well. It's the opposite for robots with rear-wheel drive; the robot will go forwards like an arrow but tends to spin off to one side on reverse. There is a scientific explanation behind it to do with acceleration and the robot's centre of gravity but I'll be damned if I remember fully what it is.

The problem is exacerbated by the Electronize speedos. Because it's relay control, they'll click on at different rates before applying proportional control so if one's clicking on marginally before the other then it will give bias to that side of drive. By the time the other one kicks in, the spin is already happening and hard to correct. Add to the fact that the drive motors are facing opposite directions so while you're driving forwards, one motor is spinning in the opposite direction to the other, and electric motors that aren't neutrally timed will go faster in one direction than the other.

The best thing to do is sit down with your robot (wheels off the ground) and move the transmitter stick forwards and backwards slowly. Watch the wheels and see if one starts turning before the other; use the rotary controls on the top of the Electronizes to make fine adjustments to when the wheels start turning so that they're as close to starting up together as they possibly can. It won't fix the problem but it might help lessen it. The alternatives would be a gyro (as mentioned) or even switching to a dual ESC or some TZ-85s in the future, basically something that has much finer control than Electronizes.

[mrsam]

I'll see how it handles with the mixer but a gyro is definitely on the cards at some point

[razerdave]

Considering your robot drives round the front it may not be a bad idea to add a gyro for ease of driving, but it's up to you.