Re: Minibot climb rate
 

What's the blue broom-hook thing at the top made of ?

Re: Minibot climb rate
 

if you're referring to the clip, its actually blue pvc pipe!

Re: Minibot climb rate
 

are you using the stock 52:1 gearbox? and are those 4" wheels ?

Re: Minibot climb rate
 

Based on a quick comparison in proportions to the opening in their deployment system, my guess is they are 4.6 inch. It looks like they are made of PVC and wrapped with surgical tubing.

Re: Minibot climb rate
 

Stock gearboxes, I modded some gearboxes to 10:1 but I didn't invest much thought into them after. The wheels are actually around 5.5", the picture angle is misleading. They use a 4" to 3" PVC pipe fitting for the wheel rim and its 3/8's surgical tubing. Im pleased with the way they came out, and can safely say its a unique design (unlike many little screamer bots out there).

Re: Minibot climb rate
 

pi*5.5" wheel diameter = 17.3" wheel circumference.

90"/17.3" = 5.2 wheel revs to climb pole

(5.2 revs)/(2.2 seconds)*(60 seconds/minute) = 142 rpm

At that speed, the motors are generating virtually no torque.

Somebody please check my math.

Re: Minibot climb rate
 

He noted in passing that he modded the gearboxes to 10:1. Which probably puts him on the wrong side of peak power, but makes a little more sense.

Re: Minibot climb rate
 

OK, is that what he meant? I thought that was an aside. The way I read it, he modded some gearboxes but then decided to use stock (as-is) ones.

Your interpretation makes more sense I guess.

Re: Minibot climb rate
 

I also took it to mean that the gear boxes on this bot were the original 52 to 1 ratio.

The 10.4 to 1 boxes, based on our experiences and pile of smoked motors, won't work with a 5.5" diameter wheel. We ended up with ~3" wheels with our 10.4 to 1 gear boxes.

The math doesn't add up to a 2.2 sec time with 52 to 1 boxes either, unless that bot's weight is less than the total of the battery and motors, let alone the wheels and frame, again based on our experiences.

Re: Minibot climb rate
 

We used stock (52:1) gearboxes on the minibot. The average time was 2.2-2.3 seconds from bottom of the pole to the top. It weighs around 4.5-5 pounds.

If this helps:

Re: Minibot climb rate
 

Very Impressive. What type of switch are you using for the trip down?

Re: Minibot climb rate
 

Our minibot had a 3.5 second climb. Unlike a lot of robots that I saw that used magnets to hold on to the pole. Our magnets were located in our wheels and then covered in electrical tape for traction.

I have attached a picture of one of the early forms of the minibot. the magnets are underneath the thin layer of black electrical tape.

We had some problems with deployment early on, mainly due to the fact that the robot was driving down the pole, but other than that it worked reasonably well.

Re: Minibot climb rate
 

Is there any gap between the magnets, or are they butted right up against each other?

How did you secure them to the wheel?

Did you alternate them N/S ?

Re: Minibot climb rate
 

Late in the process we got a 1.7s minibot working with 1/4" tubes covered with surgical tubing. I never understood why everyone thinks magnets are necessary. If you center the minibot's mass left to right and balance the top to bottom mass difference by angling the minibot a bit, magnets are not necessary. Sure the minibot is not trying to climb straight up but it is also not trying to pull the magnets up with it - and its simpler.

Re: Minibot climb rate
 

The magnets are butted right up against eachother and are alternated. To stick them to the wheel we took electrical tape and made a loop to make it act like double-sided tape. Then we used a layer of electrical tape on top of the magnets to hold them to the wheel. Overall the minibot worked well, the main issues were silly mistakes made when hooking the battery up or when setting it up before a match (forgetting to set it to turn on). but overall when we didn't mess up before the match the minibot worked well.