Adafruit 16 channel servo shield

Other Hardware Robotics
1

Hi guys,

I want to make a mechanical arm controlled with servos via a bluetooth connection.

I recently came across the adafruit 16-channel servo shield. (http://www.adafruit.com/products/1411/)

I was just wondering if it was possible to use this shield with a USB host shield? preferably this one (https://www.sparkfun.com/products/9947)

I'm curious to know because all the USB host shields use SPI interfaces but the adafruit shield uses i2c.

If they are compatible, Is it possible to control the servos with a ps3 controller using the USB?

If it helps I am using the Arduino UNO as my master device.

2

I want to make a mechanical arm controlled with servos via a bluetooth connection.

Typically, an arm has a shoulder joint, an elbow joint, and a wrist joint. That's three servos. Add one for a gripper of some sort, and you are sill far below the 12 that the Arduino can control without a shield.

What are the other 12 servos for?

I'm curious to know because all the USB host shields use SPI interfaces but the adafruit shield uses i2c.

So, no conflicts. Not a bad thing at all.

3

I know that the Arduino can control servos without a shield but I dont want to use a breadboard, I want to keep the design clean such.

Could you also elaborate on the whole USB shield thing, like why is it okay for them to use I2c when they have SPI pins?

4

Could you also elaborate on the whole USB shield thing, like why is it okay for them to use I2c when they have SPI pins?

Why do YOU assume that the shield is doing anything with the i2c pins? It isn't. It simply passes the pin to the top of the shield.

5

Im assuming because shields have to communicate using a master slave mode (i2c or SPI) they have to know that the other one is there won't be a connection right?

6

Im assuming because shields have to communicate using a master slave mode (i2c or SPI) they have to know that the other one is there won't be a connection right?

No. The Arduino might use SPI to communicate with a shield, but that doesn't mean that the shield needs to know anything about I2C or the I2C pins.

7

So it doesnt matter if the USB host uses I2c or SPI?

On another note I was thinking about how you said I won't need a shield, I was thinking stacking a USB for bluetooth of course.
But if I do that, the USB host shield I wants uses pins D13 -D9, does that mean that I will have pins D8-D2 to control digital servos with?

8

So it doesnt matter if the USB host uses I2c or SPI?

You care to define the convoluted logic you used to arrive at that conclusion? Of course it matters. But, if shield A is using one process, shield B can use the other with no interference.

I was thinking stacking a USB for bluetooth of course.

Not a snowball's chance in hell. The questions you are asking tell me that you are not prepared to write a USB driver for the USB Host shield to talk to a piece of (bluetooth) hardware.

But if I do that, the USB host shield I wants uses pins D13 -D9, does that mean that I will have pins D8-D2 to control digital servos with?

Yes, the pins D2 to D8 will be available.

9

PaulS:

So it doesnt matter if the USB host uses I2c or SPI?

You care to define the convoluted logic you used to arrive at that conclusion? Of course it matters. But, if shield A is using one process, shield B can use the other with no interference.

SO i'm RIGHT, if it can use both than really why does it matter?

I was thinking stacking a USB for bluetooth of course.

Not a snowball's chance in hell. The questions you are asking tell me that you are not prepared to write a USB driver for the USB Host shield to talk to a piece of (bluetooth) hardware.

Don't need to do all that :wink: chuck a bluetooth dongle in there, connect it to the ps3 controller and you're ready to go
as explained on this video https://www.youtube.com/watch?v=q3vXTX6Qe54

But if I do that, the USB host shield I wants uses pins D13 -D9, does that mean that I will have pins D8-D2 to control digital servos with?

Yes, the pins D2 to D8 will be available.

10

Yeaa....

kinda new to the whole quoting thing :~