ROBONOVA-1 from Hitec Multiplex
 = COMPLETE TORSO REPLACEMENT/UPGRADE - PAN WAIST & HEAD

  

Well, I had to put my Robonova-1 under sedation for this one. Surgery like this isn't easy! It's a very involved modification, and hopefully the information you find on this page can be helpful if you choose to try it with your robot.

BRACKET FABRICATION

I started out by making several critical measurements, and mapped them out on aluminum plate. When I felt confident enough that everything was correct, I cut out the blank using a band-saw and drill. The large holes were done using a Uni-bit. All edges and corners were rounded followed by some emery cloth.

 
My father-in-law bought an aluminum break for fabricating storm doors/windows and figured I'd give it a shot. The bend radius is not as acute as I'd like, but worked none the less. The pictures (above) show the hip bracket, and (above right) with servos installed. Take note of the center servo. This will allow the rotation of the upper torso region later on. The downfall of this is it is now located where the batteries were. Don't worry, I took that into consideration...

Here we see (above) the hip with legs. Even more important, the beginning of what will soon be the upper torso. Now in order for another HSR-8498HB servo to fit between the shoulders, I increased the gap between the two by about 6mm. Since the batteries needed a new home, I took advantage of all that wasted space above the shoulders. What space you ask? Here's the trick, I found some real inexpensive 5-cell, 6v, 1200mAh battery packs, and dissected them. Two cells fit nicely (as the little red arrow in the above pic shows). The fifth cell will become part of the head later on, and all will be wired together in series. The arm can still bend w/o interfering with the new torso.

I've mounted the hips to the torso, modified the RN-1 plastic chest plate, and screwed it in place. Mounded under it is another HSR-8498HB for the head. Next, a new pinhole camera head and the grips...

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Okay, lets backtrack a bit. The more I look at it, the worse it bugs me. The lower torso bracket just sucks as far as I'm concerned (picture below-left), so I'm scrapping it and starting over. The picture (below-center) shows my new blank. This one will be so much better once it's bent correctly (below-right). It's much lighter in weight and has a taper to spiff up the appearance when combined with the upper torso.

Since I had my bot torn apart again, I took advantage of it and tended to the other parts. I removed excess material that further lightened it up, yet still kept its structural integrity in tact. ...And boy, don't they look sharp in black! I don't have a lot of time before the competition, so I simply primed and painted them instead of having them anodized. He'll look a bit Frankenstein-ish, but put on a show none the less.

The upper shoulder/neck/battery compartment bracket (above-left), and the pair of chest brackets (above-right).

The back bracket (above-left), and the upper torso base plate (above-right).

 
The head/camera component encasement (above-left), and its accompanying base plate (above-right).

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I went over areas of each part with my air-brush to highlight or diffuse the angles some. Reassembled the head and torso, threw on the grips, and presto! A RN-1 with 20 D.O.F.

As you can sort of see from the picture (above), I  utilized the existing chest plate. I had to cut out the Hitec logo area  and mount it to the waist servo.

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BATTERIES

At this time, I still was using the 6v Ni-MH batteries. I initially had bought a few 5-cell packs from the hobby shop, tore 'em apart, and made up a custom array of cells. I paired two sets of two to be mounted in each shoulder, and the fifth cell, in his mid-region. They were wired in series the same, just distributed. That may not have been the best way around it, but it suited my needs for the time being... or so I thought.

Since I added the extra D.O.F. and the servos to boot, my batteries weren't lasting very long at all. Normal run-time for the standard RN-1 is approximately 45min. to an hour. I was seeing more like 15min tops. The HSR-5995TG can draw a maximum of around 5 Amps in a stalled state alone!

I took care of it by heading once again to Phill's Hobby Shop to inquire about their Li-Po selection. They introduced me to several verities. I ended up snagging four Thunder Power 7.4v Li-Po packs. Two of them rated for 1230mAh to simply use while programming or for backup. The other two, at a beefier 1900mAh, would be strictly for competition and demonstration. I probably went a little overboard I know, but believe me, I don't have to worry about power any longer.

The two Li-Po packs are wired up in parallel to a 6.0v regulator. Now Li-Po's are dangerous... they can literally become great big fireballs if you don't watch it. They are volatile if exposed to air or charged incorrectly. If you plan on wiring these types of batteries in parallel, be sure that they are balanced. Meaning, You need a charger (or monitoring system) that will insure each cell is being discharged/charged the same and tops off at exactly the same voltage. I even went the extra length to make the leads from the battery to the regulator equidistant. I didn't want to give any head-way in influencing one cell to drain faster than the other.

MORE FABRICATION

Here again, I had to fabricate some new brackets to house the batteries. The feet were the best candidate, so there they went. I left the front and backs open for easy access to the batteries when needed changing. I made four little "covers" that slide into the foot to further protect the batteries form possible puncture, yet come off easy when the need arises.

With the regulator, battery leads, additional servo leads, etc... I had to make rear-waist and new back-torso plates to house all of it.  The back-torso plate looks much like the RN-1's plastic back, but is made from aluminum and doesn't have the constrictive sides. When the waist pivots, it twists with it a bundle of servo & power leads. The more open back gives me a little more slack in the lines.

Joining the plastic chest-plate and aluminum back-plate, are two "shoulder" brackets. Under each rests a GWS PG-03 piezoelectric gyro.

...This is where I'm at right now. More coming soon!