If you don't have enough money to get a Nao robot, here are the next best 3 solutions.
1- The soccer robot: Darwin-OP
Actually, the first alternative to a Nao robot is not cheaper than Nao, but you can build it yourself, customize as much as you want or buy it in kit if you prefer. It's called the Darwin-OP.
OP stands for Open Platform, and the robot is both Open Source (running the popular ROS from Willow Garage) and Open Hardware: you can get the plans for every part for free on the net.
You can also buy directly from the Korean robotics company Robotis, which makes the popular humanoid robots Bioloid.
The Darwin-OP has a better CPU, but fewer sensors. It is overall faster and lighter, and was optimized to play soccer at Robocup. Nao on the other hand was designed primarily as a research tool, and offers near endless possibility as well as a powerful development software Choregraphe. The debate about Nao Vs Darwin-OP is hot, but not so important since the robots are actually quite different.
2- The hobby robot: Bioloid
Another humanoid robot from Robotis is the Bioloid. What is cool with the Bioloid is that it costs a lot less than Nao or Darwin-OP, but can still do some autonoumous behaviors.
While you can buy the humanoid kit for Bioloid, you don't have to make a humanoid robot out of it. The main feature of Bioloid are the servo motors that can be plugged in series to make any shape of robots.
A PhD student from my University told me he conceived his Master Thesis humanoid robot using Bioloid servos, but following his own design. He liked that the kits require no cabling, which is quite a problem in itself for humanoid robots with 20+ motors.
3- Make your own robot?
There are a lot of other kits to create your own alternative to the Nao robot. To name a few, you have: Kondo robots (Japan), Robonova, Manoi... But it's always different if you can actually build your very own humanoid robot.
It will sure be hard to design the robot as you have to take into account: the electronics (motors, motor drivers, Micro-controllers, wiring everything), the mechanical parts (which material, weight vs power, not blocking any articulation), and the AI (keeping balance, create a walking pattern).
These are all very complex problems, and unless you have a lot of time and knowledge, you will need help. The best would be to form a team, like they do for Robocup. Once you managed to make one, you can easily copy it for other people in the team. And the sense of achievement for creating such an awesome robot is really great.
1- The soccer robot: Darwin-OP
Actually, the first alternative to a Nao robot is not cheaper than Nao, but you can build it yourself, customize as much as you want or buy it in kit if you prefer. It's called the Darwin-OP.
OP stands for Open Platform, and the robot is both Open Source (running the popular ROS from Willow Garage) and Open Hardware: you can get the plans for every part for free on the net.
You can also buy directly from the Korean robotics company Robotis, which makes the popular humanoid robots Bioloid.
The Darwin-OP has a better CPU, but fewer sensors. It is overall faster and lighter, and was optimized to play soccer at Robocup. Nao on the other hand was designed primarily as a research tool, and offers near endless possibility as well as a powerful development software Choregraphe. The debate about Nao Vs Darwin-OP is hot, but not so important since the robots are actually quite different.
2- The hobby robot: Bioloid
Another humanoid robot from Robotis is the Bioloid. What is cool with the Bioloid is that it costs a lot less than Nao or Darwin-OP, but can still do some autonoumous behaviors.
While you can buy the humanoid kit for Bioloid, you don't have to make a humanoid robot out of it. The main feature of Bioloid are the servo motors that can be plugged in series to make any shape of robots.
A PhD student from my University told me he conceived his Master Thesis humanoid robot using Bioloid servos, but following his own design. He liked that the kits require no cabling, which is quite a problem in itself for humanoid robots with 20+ motors.
3- Make your own robot?
There are a lot of other kits to create your own alternative to the Nao robot. To name a few, you have: Kondo robots (Japan), Robonova, Manoi... But it's always different if you can actually build your very own humanoid robot.
It will sure be hard to design the robot as you have to take into account: the electronics (motors, motor drivers, Micro-controllers, wiring everything), the mechanical parts (which material, weight vs power, not blocking any articulation), and the AI (keeping balance, create a walking pattern).
These are all very complex problems, and unless you have a lot of time and knowledge, you will need help. The best would be to form a team, like they do for Robocup. Once you managed to make one, you can easily copy it for other people in the team. And the sense of achievement for creating such an awesome robot is really great.