Re: [Oap-discuss] Bill of Materials, OAP Motor Driver Module

[Dafydd W. <dwa...@us...>]

I think it's still possible to get hold of the Magnevation board kit
(http://www.magnevation.com/oopic/pwmx2/index.htm) although it seems to
be getting rarer:

 http://www.robotstorehk.com/motordrivers/motordrivers.html

Dave Everett wrote:
> The Sabretooth board. It's dual motor, 32khz and can handle 5A.
> http://www.lynxmotion.com/Product.aspx?productID=576&CategoryID=10

The only problem I can see with that board, just from looking at the
information on the web page, is that it probably isn't compatible with
the OAP Motor Control Module (MCM).

The control options on this Sabretooth board appear to be Analog, R/C or
serial. Of course, just because the web site doesn't mention any other
ways to interface with a host controller, this doesn't necessarily mean
that there aren't any.

To be compatible with the OAP MCM, the H-bridge driver must be able to
be directly driven using TTL-level PCM control signals at 20kHz, and be
capable of being driven in locked antiphase mode (instead of
direction+PWM). In locked antiphase mode using the old Magenavation
board, the 20kHz PCM signals from the OAP MCM directly drive the
direction (DIR) inputs of the LMD18200s.

The OAP MCM was originally designed with the LMD18200 in mind, but that
obviously doesn't mean that other H-bridge motor drivers won't be
compatible, as long as certain criteria are met.

Designing a custom motor driver board around a pair of LMD18200s would
be quite easy - you can see that from the simplicity of the old
Magnevation board. The data sheet provides all the information you need.

An alternative is to look for existing LMD18200 boards. I did a quick
Google search, and found a couple of interesting low-cost products:

 http://www.superdroidrobots.com/shop/item.asp?itemid=583&catid=5 (two
required)

 http://www.sparkfun.com/commerce/product_info.php?products_id=747