Last night I took some more pictures of the assembled base. I also weighed the base. It came out to 26+ pounds! That’s what 1/8″ steel will do for you! Now on to the pictures –
Views from the front, back and one side.
Side close up.
The back now has a power switch. Also the power bus connectors I got from Adafruit. They make one convenient place to hook the master 12V and Ground.
In the front there is a 5″ wide electronics shelf. It contains the Motor Processor (UNO), DRI0018 Motor Driver board, and a 5V power supply. The motor controller will communicate by I2C to whatever Brain is mounted to the upper. The upper portion is designed(?) to be interchangeable. I can put a Telepresence top on, a Manipulator arm, or a Machine gun :-). It is limited only by imagination. Currently I have a Bluetooth module on the motor controller to send commands to for testing.
Well that is all for this year. I will be traveling and visiting the Colorado homestead for all od December.
I have been traveling for the last month so things we pretty much on hold.
However I got lucky and got some surplus 14″x15″ steel prototype plates. These suckers are 1/8″ thick. This makes for a good base and frame. All the holes are tapped for #6-32 screws which makes life nice. They came with additional pieces that I will use to tie two plates together. There will be an upper and lower plate tied together. This idea is that this will be a self contained base that I can build whatever upper part I feel like and interchange uppers.
This shows the wheel mounted on the plate. I mounted the wheels inside the the edges for a cleaner look. I had to cut openings for the wheels. In 1/8″ steel it was no easy job. All the other holes were already in the plate.
(Those in the know may recognize these as VV bases. The were being thrown out so I got a couple.)
Here are the motors mounted on the plate. Notice the screws for belt tension on the outboard side. This may be modified later, but for now it seems to work.
I did a lot of work on Sunday mounting the electronics and power distribution. However I forgot to take pictures. I will take them tonight and post tomorrow.
I have re-built the chassie and drive system. I will also use Bluetooth for the control link. This all will be documented after my trip next week.
However, with Halloween just around the corner, I have added a skin that is a KillBot. If I get things done fast enough – the head will slowly open, they will take their candy, and the jaws will then slam shut. If I can’t get it done in time, I will just prop the head open.That thing on top is a LED strobe that also plays scary noises. It’s motion/sound activated.
Here are some pictures:
Also a look at some of the internals.
I changed my motor drive system/wheels to use electric scooter wheels. They are from a Razor 200ES from http://www.electricscooterparts.com. Each one includes a drive cog for a belt built in. It also included a axel and brake which I did not use. The wheel cog has 72 teeth and the motor cog has 13 teeth. This give a wheel speed of 0.18 of the motor speed. The motor full speed is 600 RPM at 12v. This has proved much more successful.
After Halloween I will remove the Skin and Teeth and get back to your regular robot build.
I just got back from a vacation in Colorado, so not much is new.
Intel has released the Galileo board. This is a board that has an Atom processor and an Arduino Shield connector. It also include USB OTG as well as a PCIE connector. Plus much more. This look like a great board for the Brain of my ‘bot. All at a very good price. Here is a link: https://communities.intel.com/community/makers
Back soon with updates, but I will be traveling from Nov 4 to ???? so I don’t know about progress.
If you view this blog please leave a comment to let me know someone out there is looking at it. – Thanks
Today I received two Tiva Launchpad development boards from Texas Instruments. TI had a $25 sale coupon that I used, so I only spent $0.98 for them.
These are the successor to the Stellaris Launchpad boards that I was going to use. TI revamped the product names and put a more capable chip on the board. This chip now ha s16 channels of REAL PWM control as well as Quadrature Encoder processing hardware. I will upgrade the motor controller board to this even though an Arm Cortex M4 is really overkill. It has 256Kb Flash, 32k Static ram, 2k EEPROM, 16 PWM outputs and runs at 80Mhz!
I also found really interesting link to a supplier: http://www.superdroidrobots.com/shop/ has a lot of really interesting and sometimes hard to find stuff. It looks like I will get my motor drive sprockets and chain there.
Let us not forget the Mad Scientist Hut http://madscientisthut.com/ in Lyons, Colorado. Good stuff here. I especially like the Magnetic Rotation Encoder, no optical involved. I hope they are OK with the flooding.
I have moved my web page/blog over to WordPress. The previous link will still work.
I have spent lots of time working on my Bot. He/she now has a partial body and made his first test runs across the floor.
However I have found out a few things that have caused me to stop work and do a major rebuild of the drive system.
This weekend I was a volunteer at Portland, Oregon Mini-Maker Fair. I had a change to observe several robots such as Asto-Mechs (R2-D2 type), Lego, Combat Bots and Loki.
I have a long talk with David Shinsel creator of Loki. (See: http://www.dshinsel.com/). Dave and I actually work at the same Intel site and it turned out that our thought processes in a bot are the same. What I was doing was almost exactly what Dave had done with Loki. I just am using more local controllers.
One thing I saw was that no one was using direct drive of the locomotion motors. Since I have been having headaches with my system I have decided to rebuild the base.
The base will now be a framework instead of a solid pan. Each motor will drive and axle via a toothed timing belt. This will isolate the motors and wheels from any vibration an jerking. It also will allow flexibility in mounting the motors.
I probably will have a prototype by the end of the month. First I have to get the parts!
August 21, 2013 Hi, I’m back after a business trip. No pictures today.
I rebuilt the main structure using 3/8″ & 1/4″ 36 inch threaded rods. There are two 3/8 rods by each motor and two 1/4 in the front and back as well as one in the center. The 3/8 will support the shoulder/arms when I get around to adding them. I used three pizza pans on the body spaced out for holding equipment. I have two more as spares if I need to add more.
The body covering is a piece of 36×48″ sheet metal from Home Depot. This is used for duct work. It will be wrapped around and secured with sheet metal screws.
I worked on the head, but the body filler is not holding. On the weekend I will fiberglass the whole head. I stuck on 2 googly eyes from Michaels (40mm) just for fun.