I've taken a look at what's out there for the Tamiya 70097 gearbox, and decided to design this chassis :-)
Major design features include a twin deck and parallel I beam construction for rigidity; all moving parts,including the turret mast are inside the diameter of the chassis - nothing protrudes (Frits's request); the internal beams fully support the output shafts from the 70097 - a sorely lacking feature on current chassis... and my personal favorite, an engraved protractor on the top deck. Makes it easy to see and adjust code for turning radius.
Frits, its setup to use the 203:1 gearing in this photo, but it can also use the 58:1 gearing by just changing the gear ratio on your gearbox and using the rear set of mounting points on the chassis.
Will this fit the design you wanted for nothing protruding from the diameter of the chassis?
Thanks Dan. I really like Thanks Dan. I really like the protractor as well - it really serves a nice purpose that I have personally needed and I suspect other’s have as well.
What is it? Plexi, lexan acrilic? To the point, can it be drilled or is it the kind of stuff that cracks and explodes if a drill bit even looks at it funny? (I have had some bad experiences in the past)
Also, you mentioned doing some custom work, is it a huge deal to streach this to an oval or elipse to allow 2 Tamiya gearboxes and 4 wheels? -I might want to talk seriously with you.
Chris, it’s plexi. You gotta go slow with a bit or it will crack - the easiest way for you to make a new hole would be to pierce the plexi with an old iron tip on your soldering iron. No worries about cracking then.
Not a big deal at all to cut you something custom. If it’s based on a current design, I should be able to modify to suit your needs.
Yup, I sure do know about the plexi… I used to do a lot of upper-end car stereo work and have drilled, heated and bent, sanded and polished more plexi then I care to think about. Actually, my little trick has been to sandwich the plexiglass between two pieces of thin plywood with a couple good clamps and then drill. At any rate, thanks for the responce, I need to get some thoughts in order and I will be getting in touch with you in the near future. --Great looking site by the way, good stuff.
Something like Something like http://www.noplabs.com/twinmotor/twinmotor.html incorporated in the design for gear encoding would be especially useful. Without good odometry it is very difficult to achieve accurate motor control. I’ve been using the Hamamatsu optical encoders in a number of my own designs and they are very easy to work with, being rugged and reliable and so tiny they will fit in just about anywhere. Their only drawback is that to the best of my knowledge, the only place that you can buy them is http://www.acroname.com however I’ve been very happy with their standard of service.
That looks great! You really got me thinking with the whole “articulated” idea… I am also thinking about servos for drive instead of the tamiya gearboxes -The only reason I am thinking this is to get past the “one motor is faster” problem. (With servos you can just change a variable to control speed. On the other hand, the gearboxes seem a bit more rugged and I sure do like the ability to change the gearing -not to mention the fact that you have already done the design using this unit!
One queston,
Do you have an idea of the overall size with the 4 wheel configuration? I am thinking of using a picaxe 40 I have and the board is a little big.
–Can’t wait to see the draw up on the articulated unit!
- Let me know when you have the design solid and I will keep thinking of any extra holes I might want. -Looking forward to firing up my pay-pal!
