Let's Make Robots!

What would you want on a Propeller Quickstart "do it all" shield?

After playing with the Propeller Quickstart, I'm thinking it could use a "shield" to make it more "Arduino" like.

Something like the Mega Sensor Shield, but with a few more goodies. I'm quite a newbie at electronics, so pardon my innocence..... ;-)

 

External Power Supplies

* 3.3 and 5v isolated and regulated for sensors and the Quickstart

* 5v isolated and regulated for Servos

* Jumper selected, all inputs

Analog to Digital converter

* 8 channels (ADC0809-N)

* Jumper selected, 8 inputs

Input Pin Resistors

* for 5v sensor Data (3.9k)

* Jumper selected, all inputs

ICSP Header

SD Card Reader

Shift Register(?)

RTC(?)

 

Any ideas for more? Less? What would you want on a Propeller Quickstart "do it all" shield?

Maybe a couple of ATTINY84's to offload some work?

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Propeller Memory Card

Human Interface Board

WIZnet Ethernet

There are also other boards make by third parties.

I like using 74HC595 serial to parallel to add outputs to the Prop. With PASM you can drive the '595 chips fast enough to get them to output PWM (as I did with my RGB LED arrays).

74HC165 parallel to serial shift registers are an easy way to add extra inputs to the Prop. I'm pretty sure the Prop could read the '165 fast enough to use the chips to read quadrature encoders as long as the QEs weren't too fast (the Rover 5 encoders should be readable with a '165 chip). This has been on my todo list for a while. I even made a little PCB to make it easier to connect the encoders to the 74HC165 chip.

Another interesting chip is the 74xx573. I haven't used it myself but apparently they can be used to increase the number of I/O pins. Apparently it's possible to drive 144 servos with a single cog (at 1us resolution) by using these chips.

One thing I'd want on a board is a socket for the cheap nRF24L01+ transceivers. These things are cheap but the do use a lot of pins. This is one application were a chip like the ATtiny84 could help. I think an ATtiny with a UART would probably be a better chip for this application. With an UART, the Prop could use one of the multi-port serial drivers so communication with the transceiver wouldn't tie up a cog. (SparkFun once had a Nordic fob with five buttons, a Nordic nRF24L01+ chip and a ATtiny24. The 24's memory was very full with the very basic program. Many thought it was too bad they didn't use an '84.)

I've thought a lot about this sort of a thing. One problem I see is so many of the chips I'd want to use are cheaper if you buy it on a small PCB from China. You can buy the Nordic nRF24L01+ chip by itself, but it will cost you more than a complete module would cost off ebay.

I agree with TinHead's suggestion of a motor driver but which one? The driver used depends heavily on the size of the motor. How many motors? Two? There are lots of robots with four motors.

One feature I've seen on a lot of addon boards for the Prop is a cutout and traced positioned to make it easy to connect a Wii Nunchuck or other controller with the same connector. The PCB itself is the connector and no extra part is required.

I hope all these decisions don't drive you crazy (it's too late for me).

 

I figured you would have some great ideas... :)

The cards that are avaialble, other than the memory card, well, they take over your entire Quickstart... they don't seem to expand it.

I like the memory card idea, and to get nRF24l01 tranceiver on there would be great too... Increasing the I/O would be great, I'm going to need to learn how to make these serial/parallel - parallel to serial shift registers work.... next on my list.  

I'm playing with the ATTiny84's right now, and really enjoying them, making IR beacons for the RoxIndoorPositioningSystem. I am interested on integrating the ATTiny's with the Propeller....

I'm not big on having a motor driver, as they need some power and cooling.... I'm making large robots, so space is not concern for me right now, I like my motor driver right near the motors and batteries too....keeping the big wires short. 
But.... that being said, it certainly wouldn't hurt to put in a pair that can run some small stepper motors or other accessories (arm, claw, winch, bottle opener...) What would be a very efficient lower power chip? How many channels would be feasable?

How about a speech synth chip?

 


My wife keeps looking at my bot in the office and asking:

"When is that thing going to be useful and bring me my wine?"

 

YOU need motorz drivers yes!

If you are talking about a "do it all shield"  it would be appropriate to have motor drivers as well as multi-axis accellerometer/gyro like the MPU-6050

As for which motor controller,  AdaFruit's Motor Shield V2  uses a pair of Mosfet TB6612 H-Bridges for higher current capabilities to drive four DC motors, or two Stepper motors, or one Stepper and two DC motors in a compact footprint...

And as Duane said,  74HC595 Serial to Parallel and 74HC165 Parallel to Serial would go a long way to making the Prop more interface friendly.

And a microSD card connector would be a great asset. I'm not sure why developers use Standard SD cards on these things?

Sounds like an aggressive project...  looking forward to seeing what you come up with.


SD cards seem cheaper around here and whenever I have bought a microSD card it has been supplied with an SD card adaptor too.

(don't go there!) 

microSD cards are used for almost every smartphone on the planet these days, so the prices are just about on par now, and their footprint is less than 1/2 that of the equivalent SD.  When we're making robotics controllers, size matters...

I could never figure out why the Pi guys put that SD card holder right on the edge either, just waiting for it to get bumped and snap off.  It's such a prevalent problem, that you can now buy repair kits for it!

 

 

Tiny84's for offloading work? Got 8 cores there, dont think any offloading is required :P

8 cores, but not near the I/O of a Mega....  maybe the code for the shift registers? or offload a task that needs only a single value, but requires multiple pins to complete....
(keep in mind, I know little of electronics, so I may have have pie in the sky ideas.....)