Let's Make Robots!

How expandable is the Picaxe-25?

Hello All.

I'm looking to build the "Start here" robot so I can learn some basics but I want to know how expandable the Picaxe-25 project board is. I would eventually like a robot with more than two motors but it looks like the L293D motor driver can only handle two motors at a time. Is there a way to use the Picaxe-25 project board to drive more than two motors? Are there other chips that will fit on the Picaxe-25 besides the L293D that will drive more motors?

I'm trying to see if this board will be able to grow along with my ideas/skills or not.

Thanks.

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

on how to build yellow drum machine he has connected annother motor driver to the outputs (although i dont quite get how this works

http://letsmakerobots.com/node/112 (The Yellow Drum Machine page) and you might get a better audience.

The following link offers a way to drive 2 motors with 2 pins, plus some extra components. It is admittedly more advanced than just sending a bit to each 'side' of the motor to control its direction.

http://letsmakerobots.com/node/17370

So if I build a motor board with more motor control chips on it the Picaxe-25 (or I guess more appropriatey the PICAXE-28X1 chip) can send commands to those chips to drive the motors? Is that right? I see the PICAXE-28X1  has 17 outputs. In theory, would that mean you could send info from it to a chip with drivers for 17 motors or does it take more than one output per motor. Sorry, I am very new to this.

FYI, Frits created a walk through of the project board, which you should read over as it is very helpful. http://letsmakerobots.com/node/75

To use the motor control chip (or pretty much any dual h-bridge), requires four controller outputs from your processor (the Picaxe, in this case). This allows for bi-directional control of two motors. If you added an expansion board with another dual h-bridge motor controller, you could control two more motors in either direction using another four outputs of your Picaxe.

You can re-map some of the the i/o ports of the Picaxe if you need more outputs. Read the Picaxe manual for more info.

Thanks, excellent info. Exactly what I needed. I hadn't seen that walkthrough.

You can always build your own board to get more out of the Picaxe. The project board gets you basic two-way motor control, plus inputs/outputs for other actuators and sensors. You could do a lot of different things with that.

However, if you want more than two motors, you'll need to build a board.

There's also a project board that works with both the Picaxe-28 and -40 parts. However, there is no on-board slot for a motor control, so you would need a separate board for that anyway. I used this board, together with a DAGU motor controller board, on my GRAB-E robot.

You can see pictures of both the Picaxe project board and the DAGU motor controller board on the GRAB-E's build blog. http://letsmakerobots.com/node/11208