A git repository has been created on github to host the code for the robot. It can be found at http://github.com/justintconroy/SIGBot-Jerry-Sanders.

Robotic Arms

A lot of these seem to be toys and are probably less than useful to us.

We probably actually want to build something like http://www.lynxmotion.com/images/html/build118.htm, but the kit they sell is absurdly expensive. I think we'll just buy the servos and try to get the machine shop to build something similar for me.

Also see: http://www.lynxmotion.com/ViewPage.aspx?ContentCode=assem01&CategoryID=19#alum

We talked to Scott in the machine shop today. He said he could build linkages for the arm for us if we get the servos. He also said he could build a simpler gripper for us, but we still need to figure out a good way to detach the string. He suggested that we talk to Charlie Mooney about the servos from the Delta Robot. Supposedly those are pretty beefy servos. He also mentioned using small lazy-susan-like turntables for the base to take pressure off of the servo turning the arm. It should be easy to mount the whole arm onto a quarter inch plate and attach that to our frame.

Charlie said that he's using HS-805BB servos. http://www.servocity.com/html/hs-805bb_mega_power.html

Wiimote information

I find that the best way to read the joystick values is to use WiimoteState.NunchuckState.RawJoystick values and scaling them to useful values. See the attached WiimoteBallTest2 for some sample code that uses the nunchuck joystick to move a ball on a windows form.

Wireless Serial Adapters

Company Device Cost Notes Links
blue giga WT12 - Class 2 Bluetooth 2.1+ EDR Module $26.66 Bluetooth http://www.semiconductorstore.com/cart/pc/viewPrd.asp?idproduct=5101
RainSun BT-20 $? Bluetooth
BlueRadios BR-C40# or BR-C46AR $75 Bluetooth
Laird AC4490 $70-80? Wireless RS-232 http://search.digikey.com/scripts/DkSearch/dksus.dll http://www.mouser.com/Embedded-Solutions/RF-Wireless-Based-Modules-Development-Tools/_/N-6f8ws/

I talked to Zuofu about this today. He said that another group has an embedded Bluetooth module that we could probably just use.

Got the Sparkfun BlueSMiRF from the other group, so hopefully this problem is solved. I think I can test it with an Arduino later.

I've attached some sample code for using serial commands with the Arduino.

ECE 395 Project Proposal

We will be building a robot to compete in the Jerry Sanders Creative Design Competition at Engineering Open House this year. The rules and general information about the competition can be found at <http://dc.ec.uiuc.edu>. We have already begun working on this project and currently have a chassis that is mostly built. For the Advanced Digital Systems Lab, we will be designing and building the control system of the robot as well as a manipulator to attach to the robot.

The control system will most likely be built on an Arduino <http://arduino.cc>. Instead of using a standard hobby radio controller to drive the robot, we instead plan on using a Wiimote. Many different libraries exist which make it easy to tap into the power of the Wiimote. By mounting a camera on the robot for the driver to see, we believe will have a superior system for driving our robot, giving us an edge over the competition.

The Wiimote will communicate with a computer, which will wirelessly send commands to the robot. The robot will have a camera that wirelessly sends a video image to the computer for the driver to see what he is doing. Driving the robot will essentially be like playing a video game.

The arm will be a fairly simple design. As outlined in the rules linked to above, the robot needs to be able to pick up balloons. Some of the balloons are air filled and on the ground. Some of the balloons are helium filled and held by strings. We can get points in the competition by collecting either kind of balloon. For the sake of simplifying our design and build process, we will only be attempting to pick up the helium filled balloons. We believe that a simple manipulator design that grabs the strings and cuts them will work best. By using two long parallel rods as the gripper, we should be able to give the driver a lot of room for error, thus making it a fairly simple task to grab the balloons.

Activity Log

2010-02-25

Made some serious progress today with the Bluetooth/Arduino combo. I realized that before I was trying to communicate with the Arduino through both the Bluetooth serial port and the USB serial port which use the same pins. So most likely, the problem was that both interfaces were fighting for control of the port and I got garbage returned to me. I'll spend the rest of the evening improving the actual messaging system.

2010-02-23

We worked with getting the wheels/motors on. We need to figure out if we have more chains at ACM or if we need to order more of them. The chain should have 26 links on it (as the motors are right now). That's 6 links off of the chain we have now. We also need to move the big black spacers on the wheels so that the chain isn't hitting the parts of the wheels that stick out. We realized, however, that we screwed up putting the bearings on. We put them on too tight and now we can't get them off. We brought it down to the machine shop and they said they would try to fix it for us. Note to self: When this is all over, do something nice for the machine shop guys.

2010-02-18

Today, I tested the BlueSMiRF with the Arduino. There is some sample code that includes some stuff doing serial commands between a computer and the Arduino. I'm working on experimenting with using the BlueSMiRF as the primary serial port for the Arduino. Stay tuned for when I get it to work.

2010-02-11

I messed with some Wiimote stuff today. I need to work more on reading data from the joystick. I think each axis ranges from -1 to +1, so I need to take that into account and scale it by the proper amount.

I also talked to Zuofu today about our wireless communication problem. He suggested I borrow a Bluetooth module that another group is no longer using.

2010-02-09

Got the shafts cut today. We'll need to measure out everything and get the keys put on (somehow rigidly attached, I'll ask the machine shop) for the wheels. I'll have to do this later because I'm out of time for today.

Also looked at more ideas for the arm. The toy ones probably won't work for us since we can't control them (without significant work). Right now we're looking into a design that we might try to get the machine shop to build for us. http://www.lynxmotion.com/images/html/build118.htm

I'm meeting with Zuofu (ECE 395 TA) on Thursday to talk about wireless communication/what to get.

Spring 2010 Update

The chassis was completed last semester. This semester, we have made the robot into a class project for ECE 395. In the first week, we took apart the constructed chassis so we could make it smaller. We had the machine shop cut 2 inches off of each beam. The robot is now a much more manageable size.

We are currently researching to build an arm for the robot. This looks promising for figuring out how to do arm assembly. They look to be a bit small, but we probably don't need something that's too big, and time is a factor here. We need something we can deploy quickly.

We are also looking at ways to communicate with the robot wirelessly. We have been looking at Bluetooth modules that act like serial ports, but have also discovered devices that only do wireless RS-232.

2009-09-17

Met with AOE and SIGBot together for the first time. We discussed various plans for the robot, some of which will be detailed later.

We also built a very simple robot for the Yahoo Hack Day competition. It was a completely remote controlled two wheeled robot. It had a rug from my front door on top of it, making it a flying carpet.