I found out that there are a few Arduino boards with onboard servo and motor controllers such as Lynxmotion BotBoarduino selling for $35.00, Dagu ''Magician'' Dual 0.8A Robot Controller selling for $30.50, and Pololu Orangutan SVP-1284 Robot Controller selling for $100.00. If I want to make a biped robot that needs at least 12 servos, which board should I buy?
An Arduino Uno can control up to 12 servos. You just need a separate power supply for the servos.
While Bajdi is correct, a Arduino UNO can also control 18 Servos using my servo library or 20 Servos using only 4 pins if using my Serial Servo library.
20 Servos 4 pins - total cost - about 60 cents
18 servos using a pin per servo (20 if you had enough pins)
The challenge you will have whatever you decide to do will be supplying power to all of the servos.
Generating the control signals for 20 servos is a piece of cake for an Arduino UNO, it uses less than one percent of the Arduino processing power.
Powering a single servo requires more power than an Arduino can deliver, figure out your power and then worry about the board to use.
Where can I get the 4017 decade counter from? I found two electronics stores but unless I combine the order with other stuff, I don't want to pay for shipping.
Combine it with the 100 dollars or so worth of batteries and chargers that you will need to drive the 18 servos, they might even throw the 4017's in for free.
Am I supposed to use the RCArduinoFastLib with a radio transmitter? My Vex Robotics radio transmitter has RJ10 tether port. How can I connect the radio transmitter to my computer? I ran 12 servos on my Arduino Uno board! Would an Arduino Mega 2560 board run about 40 servos?
Dagu makes a board with a 3A 5V switch mode regulator, the "Dagu red back spider controller". It is based on the ATmega1280 and has the Arduino Mega bootloader. I have one that I use for a robot.
Here is a video of it sweeping 48 small servos:
I ordered Orion Servo Shield from Basic Micro store. It can control 32 servos and it plugs into Arduino boards.
I cancelled order for Orion Servo Shield and ordered Dagu red back spider controller.
I got the Dagu red back spider controller and Dagu Servo Controller Shield for Spider Robot Controller today. There are no instructions on connecting the Dagu Servo Controller Shield to power source and to Dagu red back spider controller. There are two screw terminals marked "IN" and "5V_OUT". I think that the power source is connected to screw terminals marked "IN" and Dagu red back spider controller is connected to screw terminals marked "5V_OUT" but I am not sure. How should the power source be connected to Dagu red back spider controller and Dagu Servo Controller Shield? How should servos be connected to the headers on the Dagu Servo Controller Shield?