Otto-Re-Mix by Traveler218

Last crawled date: 3 years ago

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This is a really great little Robot. It was fun to build and my Granddaughter likes to watch him dance. I've built a couple of iterations of this, starting with Bobwi. The current Otto, version 3 head and body, are about the best I have seen (maybe a little small on the inside). I really appreciate all of the work that went into evolving this into what it is today. I also have to thank cparrapa for posting the 123CAD design files. That makes it much easier to customize the design.
The main problem I have with this one is that the legs are a little tight for the Servo. In the pictures, the servo wire is run up inside the leg, but there isn't really enough room for the servo to fit correctly. The only way I could get it to go together was to leave the wire hanging on the outside. Since this is for my 21/2 year old Granddaughter to play with, I didn't really like that approach. My solution was to make a channel on the inside of the leg to run the wire. I have posted the .stl file and I will post some pictures later.
I will also be making some changes to the head and body. I am using an Arduino Nano Pro as the controller with a custom wiring board. I need additional mounting posts for the board. Also, I am using 2000mah rechargeable batteries from my RC airplanes and need just a little more room for the battery pack to fit properly. I will be adding a place for an on/off switch and a recharge connector for the batteries (I temporarily cut a hole in the back to bring the recharge connector out). That should make Otto completely integrated and self contained. Once I get everything to fit, I will post it all here for your enjoyment.
Update; Just a note on the batteries. The original design uses standard AA Alkaline batteries. I decided that I wanted to use some rechargeables instead. My first thought was to re-use a 2000 mAh LiPo battery from my RC plane.The fit was a bit tight, so I decided to try a 400 mAh that I also have. I wasn't sure if the 400 mAh would be large enough, so I ran a test. The battery lasted almost exactly an hour! This battery is much smaller than the 2000 mAh LiPo and even the AA's, and will recharge in about 10 min with the charger I have. At $14 on Amazon.com it is a pretty good deal and should save a lot of money on AA, and I won't have to modify the design to make them fit:)
12-31-2016 - New pictures added with V3.1 of the head. I removed the round hole for the external power, added a switch mount for a micro-switch, and added mounts for my PC board. Pictures show internal hookup and final assembly.
*Note: One last thing on the Head. I was experiencing some interference with installing the head. The tabs where hitting the top of my servos. Not sure if this is a problem with the particular servos I chose, or if it a general problem. Anyway, I have a V3.11 Head where I shortened the tabs by around 0.75mm. If that is not enough I will raise the slots slightly when I modify the body. If anybody else would like V3.11 just let me know.
Next I will be adding a panel mount for the JST -XH (2S balance connector). This should make it easier to connect and disconnect the battery charger with less chance of damaging the wires. Since the battery sits in the lower section, these changes will be made to the body.
1-1-2017 OK, maybe my wife is right; I'm just a little bit obsessive. I updated with some pictures of the the V3.1 Body with a 2S LiPo plug. There is a clip on the inside, to keep the plug from pushing in when the charger is connected up. Also, with the modification to the tabs and slots, the head fits more securely and wont come open when being handled by a 2 ½ year old or when he falls over from vigorous dancing. It all works very well now.
It's now time to take another look at the electronics. I understand that some folks have made it work with Bluetooth or wifi and have android apps written to control him. That, and getting the ultrasonic range finder working will be my next effort.