Joined: 17 Jun 2004
Posts: 1459
Location: Brisbane
Spinderella - Hellfire Labs - QLD
Since my Fairy weight parts arrived I thought I would start a build thread.
The name may be temporary. It was suggested by someone from work and stuck in my head.
The plan so far is to make a shell spinner using a cut down 90mm hole saw as the shell. The shell will be mounted directly to a Turnigy 2204-14T 19g outrunner controlled by a Turnigy Plush 10amp 9gram speed controler.
Since the shell will be so heavy, an unmodified hole saw is 104g, the rest of the robot needs to be as light as possible. This is why I went for a pair of 3.7g sub micro servos. I weighed these out of the bag at 4.7g each. There are no mechanical stops on either the gears or potentiometer so no changes where needed there. I removed the wires to the pot and put a couple of 2k2 0603 1% chip resisters accross the pads on the PCB but the servos will only run full speed one way when the radio is on so that didn't work. I didn't check the wiring before pulling the wires off and it seems I got the order of the pads wrong. Simple fix before work on Monday where I have some enamelled wire to re wire them.
I am using a 75MHz single conversion receiver which started at 10g but is now 6g without casing, connectors, 0.1mm enamelled wire antenna and crystal soldered directly to the PCB.
The chassis will be 1mm carbon fibre epoxied together. just need the layout finalised.
Due to stock issues with HK I got a 500mAh 2 cell LiPol that is currently 31g but will have a fair amount of wire removed and smaller connectors added.
Total weight of the parts minus shell so far = 68g so needs some work. _________________ Get Some!!!
Secretary of the Queensland Robotics Sports Club inc.
Basically mini PQ. Anyway to lighten the hole saw? _________________ Steven Martin
Twisted Constructions
http://www.botbitz.com
Sat Apr 10, 2010 5:00 pm
Knightrous Site Admin
Joined: 15 Jun 2004
Posts: 8511
Location: NSW
Never thought of a hole saw for a shell spinner. Might have to look at hacking one up for uMBX v2. The tensile steel of the holesaw will epically outlast the HDPE...
Fairyweight is the same as UK antweight but is the american name for it and doesnt include cube rule. _________________ Steven Martin
Twisted Constructions
http://www.botbitz.com
Sat Apr 10, 2010 6:28 pm
Philip Experienced Roboteer
Joined: 18 Jun 2004
Posts: 3842
Location: Queensland near Brisbane
Thank you.
Please tell me it is going to have a doll on the top of it. _________________ So even the rain that falls isn't actually going to fill our dams and our river systems
Sat Apr 10, 2010 6:36 pm
kkeerroo Experienced Roboteer
Joined: 17 Jun 2004
Posts: 1459
Location: Brisbane
@ philip: I have more of the gingham material so we will see.
@dyrodium: using a battery that can supply 2.7A to drive a brushless that draws 6A would be interesting but I wouldn't use less than a 400mAh battery. I did order 400mAh cells but after a month of waiting for them to come into stock I changed the order. The 500mAh will fit fine.
@marto: I use the Fairy Weight term here to avoid confusion but I guess it didn't work. I am building to the 4" cube rule for added fun. I also only need a 20mm high hole saw so I will loose a bit cutting it down. I hope toget it under 100g with teeth. Or maybe just one tooth.
Daniel what is the smallest tap you have? Can you bring it tomorrow? _________________ Get Some!!!
Secretary of the Queensland Robotics Sports Club inc.
Sat Apr 10, 2010 9:35 pm
Daniel Experienced Roboteer
Joined: 30 Aug 2005
Posts: 2729
Location: Gold Coast
M2 x 0.4. But its a really crappy set and I'd be worried it'll snap in what your tapping. No idea what your tapping either.
Sat Apr 10, 2010 11:20 pm
kkeerroo Experienced Roboteer
Joined: 17 Jun 2004
Posts: 1459
Location: Brisbane
I got the servos working.
I first rewired the resisters and used a wire link to get them going. It turned out with the 2x 2k2 resisters the centering was way off, too far for me to trim them. I replaced one of the 2k2 with a 1k5 and one of the servos cnters with no triming and the other needs a slight adjustment. Here is a pic if others are using these servos (resisters and wire link at the top):
_________________ Get Some!!!
Secretary of the Queensland Robotics Sports Club inc.
Tue Apr 13, 2010 9:37 am
dyrodium Experienced Roboteer
Joined: 24 Aug 2004
Posts: 6476
Location: Sydney
I hacked mine last night and had the same problem with the 2K2's so ended up using a mini 5K trimpot, will try 1K5 though if it worked for you. Are they speed modded, too? For future reference the cheapo $2 turnigy servos work great their boards have no built in resistance detection (it won't back off power if you put pressure on the wheel). _________________ ( •_•)
Joined: 17 Jun 2004
Posts: 1459
Location: Brisbane
Done some more work on my breaks at work. I wont get any done for the next 4 weeks as I will be out of the country.
All the parts have been mounted onto a 1mm carbon fiber disc with all the wires as short as possible. I still need to add 3 PCB stand offs to hold a base plate on and maybe bigger wheels.
I also removed the prop saver mount off the motor and drilled and tapped 4 M2.5 holes in the rotor to mount the weapon and also tapped the motor mounting holes.
The battery wire have been changed to have just 1 plug that doubles as power and balancing plug. lots of wire removed there.
Here is the view from underneath:
And on top:
Total weight so far = 74.5g
So it looks like the shell needs to be about 65g _________________ Get Some!!!
Secretary of the Queensland Robotics Sports Club inc.
Sat Apr 17, 2010 11:00 am
Jaemus Experienced Roboteer
Joined: 01 Apr 2009
Posts: 2674
Location: NSW
Nice!
What are you going to be using for teeth on the shell?
IMHO, the foam on the wheels looks a little flimsy. maybe you could use a second pair of the 4 spoke horns layered ontop of the existing ones to make an 8 spoke wheel without a rim?
Sat Apr 17, 2010 11:31 am
Glen Experienced Roboteer
Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect
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