Beginner: Professional Development Board as a Robot Base

ndillane

Hi All,

A few months ago I purchased the STAMPworks 2 Parallax Professional Development Board (PDB) kit from Hobby Engineering
http://www.hobbyengineering.com/H2284.html - pretty expensive piece of kit by the time I paid carriage and duties to Ireland .

I have been having great fun working my my way through a few of the experiments but eventually ran out of patience and wanted to get robot building using PDB as a basis for the electronics. Although I've heard the PDB is not an ideal base for a robot (large and a bit heavy) but the PDB has loads of stuff already on it such as servo, stepper motor electronics, LCD, LED displays, Pots, switches etc etc - So I am going to give it a try

I'd really like to build the robot from pieces I select myself as opposed to buying a kit - I realize I will make loads of mistakes but just want to get going so I can some of them out of the way soon

I'd welcome any advice and feedback on what I have on order so far (bit late for advice you say !)

POWER - I got myself a really nice versatile NI-MH charger and 20 X 2800mAh AA NI-MH batteries. I also got two 2 x 10 AA battery holders which will give me in theory 1.5V x 10 = 15V but in reality seems to be providing 12V. I intend to use this to to power the PDB directly as it needs 12V. I am also initially going to use this to power everything (servos and sensors) - ANY IDEAS IF THIS WILL WORK ?
I should be OK weight wise as 10 AA batteries are around 1/2LB and the PDB is about 1lb so over all should be around 2.5 lbs with other bits and pieces

BASE

1 x BR988632 - Octabot II Expandable Robot - Black from British Robotics
http://www.orientalcommodities.co.uk/pictures/BRGordon/BR988362Desc.htm
Includes 2 servos and wheels

SENSORS/LEDS also from British robotics
2 x BR800200 Optical Sensor, in Plastic Housing
2 x BR850341 - Blue LED T1 3/4 4000 mcd
2 x BR000136 - Sharp GP2Y0A21YK Distance Sensor

All going well I may use the Stepper Motor that came with PDB kit as the basis for a gripper or camera amount thats a while away yet.

TEXT-TO-SPEECH
SPO3 from http://www.warburtech.com/modules/sp03.speech.synthesizer/
This seems to like I2C for triggering stored phrases but BS2 does not do I2C (?) so I was thinking of using the RS232 interface on the PDB to do this as SPO3 also has this option - ANY ADVISE HERE FROM ANYBODY as I can't see anything on the web about using this with a BS2
Alternatively I guess I could get a BS2P which will do I2C and give me extra memory for future projects - but it is a bit pricey

Any feedback or advice much appreciated

tks
Noel

Zoot

will give me in theory 1.5V x 10 = 15V but in reality seems to be providing 12V

- NiMh batteries have a nominal rating of about 1.2v (see the print on the side of the battery).

I intend to use this to to power the PDB directly as it needs 12V

- it doesn't "need" 12v; the regulator will work at lower voltages (9v, etc).

I am also initially going to use this to power everything (servos and sensors) - ANY IDEAS IF THIS WILL WORK ?

- if you mean you will power the servos from the Vin (the raw ~12v) you will ruin your servos. Run your servos at 5-6v for longest life. All your electronics you should run from the regulated 5v of the PDB. It is not uncommon to also power servos from regulated 5v, however, the more voltage you are regulating down to 5v and the more stuff you have hooked up, the hotter your regulator will get. You might think about two separate packs of rechargeables -- a raw 6v or so for the servos and such, and another battery pack at 6-9v for the PDB regulator (i.e., your 5v logic/electronics) supply.


This seems to like I2C for triggering stored phrases but BS2 does not do I2C (?) so I was thinking of using the RS232 interface on the PDB to do this as SPO3 also has this option - ANY ADVISE HERE FROM ANYBODY as I can't see anything on the web about using this with a BS2
Alternatively I guess I could get a BS2P which will do I2C and give me extra memory for future projects - but it is a bit pricey

- there is code available for "bit-banging" I2C on a BS2, and it works quite well, however, with all you plan on putting on your 'bot, I think that you will find your BS2 will fill up *rapidly*, perhaps even before adding in I2C code. If that is the case, you may find the $$ on a BS2p is well spent, given the 16k of programming space, the 128 bytes of ram, and built-in commands for parallel LCD displays and I2C functions. That said, before you drop $$ on a better Stamp, or on a speech module, think about buying a $1 I2C EEPROM (read/write memory) to play with. I2C is one of those protocols that once you play with it and "get it" it's cosmically easy to use any I2C device, and it's nice to practice on a device that "doesn't matter".

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
When the going gets weird, the weird turn pro. -- HST

1uffakind.com/robots/povBitMapBuilder.php
1uffakind.com/robots/resistorLadder.php

Ugha

It sounds like you've got a pretty good plan here.

I've got a few suggestions that you might consider.

There are other text-to-speech modules out there. Some are much easier to interface with a BS2.

Its clear that you want to build a really great robot that's capable of a lot of different tasks. It might pay to either get an SX to program, or have a friend program one for you to act like a
coprocessor to offload some of the tasks from the BS2 (like I2C/Servo control, ect)

If your robot is going to be especially heavy, you may have problems with your servos being unable to drive the load around like you'd wish. You may wish to consider getting a couple H-bridges
and DC motors to power your robot's drive system.

Parallax's daily deal is currently its super-powerful HB-25 motor controller. This is a great H-bridge capable of driving up to 25 amps. I'd consider two of these if you want your robot to have
serious horsepower.

Another H-bridge option is a single-chip H-bridge that can support up to 1Amp motors. I've used the SN754410 h-bridge successfully several times. It can support two motors at 1amp total
and costs under $3 on most sites.

ndillane

First off thanks for the advice and support.
Zoot - seems like I need to pay more attention if I am going to be successful !! I assumed all AAA batteries were 1.5v but you are of course correct , my NI-MH AA are actually 1.2V. No worries though as I intend to use the servo outputs on the PDB and not power anything directly other than the PDB which has regulated power. I would be interested if you could point me to any more info on how I might make use of I2C eeproms with the BS2 ti drive the SPO3
Ugha- The spec on the base/servos I have say I should be ok weight wise - good advice on the MC - might look at these once I run out of steam with BS2

Hoping to learn lots from this first attempt tks N

Zoot

I2C for a Basic Stamp 2 (orig. by Jon Williams): http://forums.parallax.com/attachment.php?attachmentid=36682

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
When the going gets weird, the weird turn pro. -- HST

1uffakind.com/robots/povBitMapBuilder.php
1uffakind.com/robots/resistorLadder.php

ndillane

I managed to get the SP03 Speech Module linked upto my PC using home made cables and have it "talking" very well. I have stored 10 phrases and need to figure out how to trigger them now using the BS2. The Pro Dev Board I am using has a RS232 port that can be used to talk to other devices. I should be able to plug my SP03 into to that and trigger the phrases with some BS2 code.
Here is the documentation on the SP03 http://www.robot-electronics.co.uk/htm/Sp03doc.shtml
If you scroll down you will see what you need to send to the SP03 via RS 232
To be honest I am not really sure at all what to do here.
Assume I will use the a BS2 pin and the Serout command to send data to the Rx pin of the SPo3
I will probably read status of the SP03 TX pin to see if it is finished speaking
Not sure what commands to send to the SPo3
Any feedback/hints or direction appreciated

Zoot

I think you are making it too complicated. The SP03 (which uses the same WinBond phoneme chip as the Parallax Emic), is 5v TTL. Your Stamp and PDB are 5v TTL. Converting to RS-232 serial, then *back* again on the SP03 seems unnecessary. Really, the RS-232 ports on both boards are for bi-directional comm. to a PC, not to other TTL boards.

In any case, I think you should pursue one of two courses, depending on your needs, desire, skill level:

- use the parallel pins on the SP03 to trigger your pre-loaded phrases. You can hook output pins from the Stamp right to the input pins on the SP03. Pro: super easy to wire and code. Cons: limited to pre-defined phrases, uses a lot more pins.

- use I2C to communicate with the SP03. This gives you full control over what it does; it only takes two pins and two resistors on your Stamp, *and* you can hook many more devices up to the same "bus" -- the same two wires can be daisy chained to multiple I2C devices. It's very very very cool. Keep in mind whatever learning pains there are with I2C, it opens a whole world of modules, chips, etc, all of which are easy to use and don't use very many pins. Pros: few pins, flexible, powerful. Cons: learning curve (unless you are using a Stamp that supports I2C commands in which case it is *very* easy).

That said, there is no reason you can't run a properly wired serial cable from the PDB to the DB-9 on the SP03. Then you would use SERIN and SEROUT (at the proper baud and settings, using the SP03 commands) on PIN16 -- on the Stamp this is the serial pin to the RS-232 D-9 port. It's the same pin port used for programming a Stamp, or for DEBUG transmissions, data logging to a PC, etc.

www.robot-electronics.co.uk/htm/Sp03doc.shtml

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
When the going gets weird, the weird turn pro. -- HST

1uffakind.com/robots/povBitMapBuilder.php
1uffakind.com/robots/resistorLadder.php

ndillane

Zoot - I have been reading quite a lot on the SERIN/SEROUT command and I had come to the same conclusion on the RS232 port on the PDB not worth using when I could use the serial on the BS2 directly. However for now I might follow your suggestion of using the parallel pins to trigger the SP03 pre loaded phrases and get back to on-the-fly conversion when I have an I2C compatible BS - which seems like the best long term solution for me
tks again for your help