There are a number of components that I have standardized across all of the 1lb robots I have built in recent years. These components are:
Fingertech Robotics TinyESC v2http://www.fingertechrobotics.com/proddetail.php?prod=ft-tinyESCv2
The TinyESC is, in my opinion, the best insect weight esc available today. The high voltage capability, current limiting and light weight make it a great option for robots up to 3lbs.
Fingertech Robotics Silver Spark gearmotorshttp://www.fingertechrobotics.com/proddetail.php?prod=ft-Sspark16
The Silver Spark gearmotors have proven to be incredibly reliable when combined with lite flite foam wheels. The gearboxes in Algos have been through 5 full tournaments across two robots without failure.
Fingertech Robotics Lite Hubshttp://www.fingertechrobotics.com/proddetail.php?prod=ft-lite-hubs
These are the lightest hub adaptors I know of for lite flite wheels. They're inexpensive and they work well.
R410 4 channel Spektrum compatible receiverhttp://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=11972
They're light, tiny, and work with DSM2 and DSMX transmitters.
It's available in a range of sizes and allows for easy assembly of waterjet cut panels.
For the remaining components on the robot, there was a good deal more decision making to be done. I knew I wanted a high RPM weapon, but with sensorless brushless motors there are occasional issues with starting torque, so a balance of torque and peak RPM was necessary. The style of weapon and motor mounting location also meant it would likely see some abuse, so low cost was a priority. When low cost is the goal, Hobbyking is the go to source for components. I eventually settled on a 1380kV outrunner from Hobbyking ( http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=14398
) for the weapon. At 11.1v, the rated voltage of the 3s lipo I was intending to use, the motor would theoretically spin at 15,318 rpm which works out to a tip speed of around 90mph with the 2" disk.
The motor suggests a 10A rated ESC for typical use, seeing as there was very little weight and size increase, I opted for the 12A Plush12 ( http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=2161
) brushless esc to give extra breathing room on that portion of the electrical system.
There's not really a set rule for battery selection, however with lipo batteries, one goal is typically to not drain the battery completely during a match. Matches for 1lb robots are normally 2 minutes long, so I wanted to make sure the robot would have plenty of battery to last a full two minutes. In combat situations, you have current spikes intermixed with low and intermediate draw periods. The TinyESC's limit each motor to 2.8A each, or 5.6A total. The weapon motor claims 7A peak, so when added together, you have a theoretical maximum draw of 12.6A. If through a strange string of circumstances you managed to stay at peak draw for an entire match, you would need to supply 12.6A for two minutes, which converts to a 420mAh battery ( (1000*Amps required) / (minutes of fight/60) ) however, as this is an extreme worst case scenario, a smaller battery can be chosen. I opted for a 325mAh battery under the assumption that 50% average draw would be an extreme case in actual use. I opted for a high end battery pack in this scale, a Thunder Power 3s 325mAh pack ( http://www.robotmarketplace.com/products/LP-TP325-3SPP65J.html
) rated at 65C continuous output, which translates to 21.1A.
The final piece of the puzzle was the mounting of the weapon disk. There are plenty of options on the market today, after looking at several options I chose to try the lightweight set screw hub from ServoCity ( https://www.servocity.com/html/lightweight_set_screw_hub__3mm.html
) and have been pleased with the results.
I use a custom power switch for my robots, however there are several off the shelf switches that have been used successfully and removable links are common in the small weight classes. Fingertech Robotics has been developing a small power switch that should be an ideal solution in the future.