This is my second autonomous mini-sumo design, and I call this one "Seeker", to follow after MicroSeeker. This one is very much a stealthy design. It is under 3" high, but it packs a lot of power into that small size. Right now, it weighs in at about 420 grams, but I still have one more tiny (1.2" x 0.75") pcb board to add, and the four bottom-facing IR sensors.
This mini-sumo is controlled by a PIC 16F877 micro-controller. The motors are Micromo 1717 gearmotors, and they are powered through a Texas Instruments SN754410NE one amp dual h-bridge. A single NiMh 9 volt battery provides the power for both the electronics and the motors. The tires & wheels are standard R/C racing tires & wheels for street touring cars. The IR range-finders are Sharp GP2D12 analog sensors from HVW Technologies, a really great local company here in Calgary.
And yes, this is a fully-operational robot right now.
If you have any questions or comments, please email me...
|March 6, 2002 -- Here's a
picture of the new chassis I am building for Seeker. It does not have the wedge on the
front anymore -- instead it has room for a AAA 6-cell NiMh battery pack to run the motors.
I still have more mounting holes to drill, and right now the chassis structure is just sitting on top of the base plate.
|Here's a rear view of the new chassis. The support bars are made from 1/4" x 3/4" aluminum bar that has been milled down from 3/4" to 5/8" high. I will be drilling a bunch of 3/8" holes in the aluminum bars to reduce the weight.|
|Here's the new chassis, with the old one next to
it in comparison. The new one is much more precisely machined. The old one is not screwed
together here, the pieces are just sitting on top of the old base plate.
The new chassis as it sits right now weighs about 45 grams more than the old version, and I need to remove most of that excess weight.
|December 22, 2001 -- Here it is with the first coat of flat black on the shell. I am very pleased with how Seeker has turned out in terms of the way it looks.|
|Here you can see it with the RF telemetry board
attached. Of course, I won't be competing with this board in place, as it makes the bot
too large & heavy, but while I am practicing and developing and debugging, it will
give me a way to get real-time feedback from the bot, as well as change certain parameters
that I can save in the data EEPROM of the main CPU, the 16F877.
The board itself is just a simple dual perf-board from Radio Shack, with the RF module mounted on one side, and a PIC 16F876 mounted on the other side. There is a 4-wire connection to this board, which includes power, ground, serial I/O, and a presence indicator. The RF module is an SC transceiver from Linx.
|December 18, 2001 -- So here it is, with the
shell pretty much finished. The final product will be painted flat black of course, but
other than that this is pretty much what it is going to look like.
It sits at a slight forward angle to make sure the front wedge scrapes the floor, and it has a couple teflon sliders in the back to keep it at that angle.
|Here you can see a rear quarter view, and the
"control panel" is visible through a hole cut in the shell.
The control panel has the on/off switch, a push-button momentary contact switch (for starting a match), a blue power indicator LED, a red heartbeat flasher LED, and a 4-pin connector for the RF telemetry daughterboard.
You can see the two white teflon slider pads at the bottom in this picture.
|This is a front quarter view. The side panels
are mostly done -- just some final filing to shape them. The dual sonars are mounted in
the front, in a mount I designed & built.
You can see the two blue terminal blocks on the h-bridge board just under the IR sensors -- these are the outputs to the left & right motor.
And yes, that big chip at the top you can just see the edge of is a PIC 16F877...
|Here's a side view. All the external aluminum
pieces will be painted flat black. I need to make some adjustments to the ribbon cable
connector that is sticking above the line of the top -- it all needs to fit inside the
shell, which will follow the contour of the side panels.
The aluminum wedge at the front has an integral spring-loaded dual bump sensor.
|And here's the front view, from the opponents point of view. Of course, once the shell is done you won't see any of the internal details, but I think this shot is pretty cool anyways.|
|Here's the front quarter view. This one has two Sharp analog IR range-finders, set at slight angles from each other. It also has a built-in bump-sensor in the front wedge. There are four IR sensors facing downwards, one at each corner. These are for detecting the white line at the edge of the ring. There are also 2 more IR sensors, one for each wheel, to keep track of how far & how fast each wheel rotates.|
|This view shows the rear quarter, and you can see the opening in the body for the UI board. The on/off switch is the slide switch in the upper left. Below that is a push-button switch for starting the competition countdown. A blue LED shows main power, and the red LED is the micro-controller heartbeat. The connector in the upper right is the RF telemetry daughterboard connection.|