the new propeller servo controller

FireHopper

I am thinking of getting one for converting my animatronic costume to, to eliminate one circut board, however, I need to be able to detect 8 digital inputs, it seems that there is 9 pins that are unused, are they easily accessable on the underside of the board? I dont see solder points on the top side,
p16-p24 seem to be unused on the schema.

anyone? [noparse]:)[/noparse]

Mike Green

Looking at the PCB, I'd say that they're not accessible. There are no solder joints on the top side.

How many servos do you need to control? The level shifters / buffers for the 16 I/O pins are bidirectional. You could use P8-P15 for your inputs and P0-P7 for your servos. You'd have to modify the control program to use P8-P15 as inputs, but you'd be doing that anyway.

Post Edited (Mike Green) : 10/15/2009 1:25:11 AM GMT

FireHopper

I only need to controll 6 servos, But I'd like to leave that part of the code alone just in case I need to controll more servos. I dont think my soldering iron has a small enough point to solder tiny wires to the pins I can barely see on the chip's edge, I can see where the unused pins are.

Chris Savage

I'm with Mike...you'd have to have modified the code to use the extra pins...You could easily use these pins by modifying the code and possibly even use the PWM32 object.

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Chris Savage

Parallax Engineering
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FireHopper

Chris Savage (Parallax) said...
I'm with Mike...you'd have to have modified the code to use the extra pins...You could easily use these pins by modifying the code and possibly even use the PWM32 object.

I do know that I'd have to hack up the code a bit, I'd just like to leave the servo controlling part alone, and just sense some switch inputs and command the servos, bypassing the sending serial commands part :>

very awesome controller btw. [noparse]:)[/noparse] my first serial servo controlled I used cost me $100 and it didnt do have what yours does, and it only controlled 8 servos!, I asked him how much for a updated one, $100 still.. and I found your PSC and was like YAY! prayers answered!

and this one takes the cake [noparse]:)[/noparse]

I'm no good soldering tiny wires though, so attaching to those pins might be hard, if not impossible for me.

iDave

You might want to try Wire Glue(www.thinkgeek.com/gadgets/tools/b70c/) I use it for small, intricate, and/or fragile(applying heat can damage nearby ic's) part of circuits. I got mine off ebay. Stuff actually works!

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"A complex design is the sign of an inferior designer."

Beau Schwabe

FireHopper,

The Propeller Servo Controller uses two TXB108 8-bit bidirectional voltage-level translators for all 16 of the servo Outputs.

One of the main goals in writing the PSC Propeller Firmware was to allow for the ability to Enable or Disable a particular servo channel and use the servo signal pin as an input to the controller. When Disabled, the unused Servo channel becomes an INPUT allowing you to read data on this pin with your program. The TXB108 bidirectional voltage-level translator helps make this possible on the controller.

See the PSD – Servo Disable and PSE – Servo Enable command in the Propeller Servo Controller USB Documentation to see how to enable or disable an unused servo channel.


So without making any board modifications or software modifications other than adding your own input routines, you could read 8-inputs and control up to 8 servos.

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Beau Schwabe

IC Layout Engineer
Parallax, Inc.

Post Edited (Beau Schwabe (Parallax)) : 10/15/2009 6:25:51 AM GMT

FireHopper

Beau Schwabe (Parallax) said...
FireHopper,

The Propeller Servo Controller uses two TXB108 8-bit bidirectional voltage-level translators for all 16 of the servo Outputs.

One of the main goals in writing the PSC Propeller Firmware was to allow for the ability to Enable or Disable a particular servo channel and use the servo signal pin as an input to the controller. When Disabled, the unused Servo channel becomes an INPUT allowing you to read data on this pin with your program. The TXB108 bidirectional voltage-level translator helps make this possible on the controller.

See the PSD – Servo Disable and PSE – Servo Enable command in the Propeller Servo Controller USB Documentation to see how to enable or disable an unused servo channel.


So without making any board modifications or software modifications other than adding your own input routines, you could read 8-inputs and control up to 8 servos.

Oh nice, That would be perfect [noparse]:)[/noparse] Now to order one or two of them when I have spare cash again.

GeorgeCollins

I have never seen this product on sale. If you can reprogram the EEPROM, it would be a great little robot controller. You can connect PING sensors, keyboards, gyros, into those servo plugs. I do it on my little quad robot. I just want a very small board. I hope you will be selling this soon, this is the Prop board I have been waiting for.

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My Robots

Mike Green

The Propeller Servo Controller is (and has been) for sale and the EEPROM can be reprogrammed. It's just a Propeller with the 3.3V to 5V level converters packaged up as a servo controller and preprogrammed to behave in a manner compatible with the older (discontinued) servo controller.

GeorgeCollins

I was able to find it by searching for servo just now, but I didn't know it existed. I know it seems like a trivial distinction between this and the protoboard. But this is what you want for a little walking robot, something as small as possible with servo connectors and battery terminals.

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My Robots