Duane, The Proto USB is also a good option.
But, the Quickstart gets power over the USB cable, making it easier to use.
Also, it has buttons and LEDs on it, so people can experiment with it by itself without a soldering iron.
The real advantage of Quickstart (and PropPlatform USB too) is that I can make a board that simply plugs in and requires no soldering.
Tubular, that's an interesting way to save money. motors wouldn't have as much power, but maybe that's not so important...
Main problem I see in tying Prop pins together is that somebody is going to drive one low and one high and poof...
Rayman, actually it seems to take more effort than that to hurt the prop. I struggled to get much more than 40mA in short circuit situation with "one low and one high". But still, it does need further investigation and/or testing to the death.
Realistically my suggestion is better suited to a raw prop chip, 2 AA batteries, perhaps a protection diode, cheap 40 pin socket, and no pcb. If (when) it fails it's at most a $8 socketed chip to replace.
I look forward to seeing what you come up with following the quickstart path
You might be right about not hurting the Prop. I remember with a DIP chip that I had a Pin shorted and was surprised that it survived.
But, I've also had a QFP chip die on me... I've always wondered if DIP is stronger than QFP for some reason...
Well, I've completed the PCB layout for "Merlin". I still think I can provide it for $15.
I was pretty proud of my quad nand circuit that took 2 Prop pins and created 4 motor states: free, brake, forward, reverse.
Just the quad nand and the h-bridge was enough to drive a motor...
But, then I found the Toshiba TB6552 that does the same thing, but drives 2 motors and costs half....
So, I've just redone my circuit for that chip. It's actually much better now and and drive pretty beefy motors (1A)...
Each way I look at it, the most useful seems to be this...
* Tamiya 89918 clear twin 4 speed gearbox with motors are usually the cheapest at ~$8.50. The 70168 is the non-clear version and is usually +$1.
* Tamiya 70101 wheel set 4@ 36mm ~$4.70 (only require 2)
* Optional Ball castor for ~$4
All available from www.robotmarketplace.com (USPS $10.40 First Class to Australia for #89918 & #70101 - omitted ball castor)
The Sparkfun Magician Chassis ROB-10825 at $14.95 is certainly attractive, but long term I am unsure about the versatility of the motors.
Then of course, there is the electronics and mounting platform.
Cluso,
DC motor gearbox directly to a board does sound like the cheapest method.
But, your total is $8.50+4.70x2+4?
The magician seems like a much better and cheaper way to go...
Still, my Merlin board should be applicable to your setup too.
I'm also still fond of the ArdBot. Merlin should work well with that too and some lobotomized servos...
Rayman: The dual motor/gearbox is $8.50 plus $4.70 for 4 tyres (only 2 are required) = $13.20. I have seen the ball castors cheaper (~$2), but I am sure this could be done quite simply and cheaper. Big cost to me is shipping $10.40 which makes it similar to buying here. But by me buying from the USA I have verified a USA source.
IMHO the motor/gearbox with 4 speeds makes this a much better solution in the long term.
I was given a couple of Robots that were built in a project in conjunction with a local newspaper (in South Australia anyway) that ran a few years ago. The project was quite neat. Here is a link http://www.i-bot.com.au/ibot/page.php?sId=1 .
Now, where did I put them??? Oh yes, they are on the boat
Comments
But, the Quickstart gets power over the USB cable, making it easier to use.
Also, it has buttons and LEDs on it, so people can experiment with it by itself without a soldering iron.
The real advantage of Quickstart (and PropPlatform USB too) is that I can make a board that simply plugs in and requires no soldering.
Tubular, that's an interesting way to save money. motors wouldn't have as much power, but maybe that's not so important...
Main problem I see in tying Prop pins together is that somebody is going to drive one low and one high and poof...
Realistically my suggestion is better suited to a raw prop chip, 2 AA batteries, perhaps a protection diode, cheap 40 pin socket, and no pcb. If (when) it fails it's at most a $8 socketed chip to replace.
I look forward to seeing what you come up with following the quickstart path
But, I've also had a QFP chip die on me... I've always wondered if DIP is stronger than QFP for some reason...
I was pretty proud of my quad nand circuit that took 2 Prop pins and created 4 motor states: free, brake, forward, reverse.
Just the quad nand and the h-bridge was enough to drive a motor...
But, then I found the Toshiba TB6552 that does the same thing, but drives 2 motors and costs half....
So, I've just redone my circuit for that chip. It's actually much better now and and drive pretty beefy motors (1A)...
Here's what they look like:
Merlin plugs into the Quickstart board and has a dual motor driver.
It has the jack for the battery plug.
It also is a half Propeller Platform adapter, for pins P16..P31.
P1..P8 are also brought out to a header.
P9..P12 go out to four servo headers.
BTW: I just noticed this low cost distance measuring thing on Digikey: 425-2616-5-ND
* Tamiya 89918 clear twin 4 speed gearbox with motors are usually the cheapest at ~$8.50. The 70168 is the non-clear version and is usually +$1.
* Tamiya 70101 wheel set 4@ 36mm ~$4.70 (only require 2)
* Optional Ball castor for ~$4
All available from www.robotmarketplace.com (USPS $10.40 First Class to Australia for #89918 & #70101 - omitted ball castor)
The Sparkfun Magician Chassis ROB-10825 at $14.95 is certainly attractive, but long term I am unsure about the versatility of the motors.
Then of course, there is the electronics and mounting platform.
DC motor gearbox directly to a board does sound like the cheapest method.
But, your total is $8.50+4.70x2+4?
The magician seems like a much better and cheaper way to go...
Still, my Merlin board should be applicable to your setup too.
I'm also still fond of the ArdBot. Merlin should work well with that too and some lobotomized servos...
IMHO the motor/gearbox with 4 speeds makes this a much better solution in the long term.
I was given a couple of Robots that were built in a project in conjunction with a local newspaper (in South Australia anyway) that ran a few years ago. The project was quite neat. Here is a link http://www.i-bot.com.au/ibot/page.php?sId=1 .
Now, where did I put them??? Oh yes, they are on the boat