Arlobot - Front/back, which way is forward?

mrsoft99

Hello All,

I'm building an Arlobot, to try to get a more sturdy and robust turtlebot. (I've been using chrisl8's notes, and they're terrific!)

My first post to this forum is perhaps a stupid question - which is 'front' and 'back' on the Arlobot? Does it even matter mechanically?

My assumption is, that the power distribution module is at the back of the Arlobot. Is that what others are thinking also?

thanks,

buddy

Duane Degn

mrsoft99 wrote: »

My assumption is, that the power distribution module is at the back of the Arlobot. Is that what others are thinking also?

That's my thinking.

I'm calling the motor with the grey cable the right motor.

Are you using a Propeller Activity Board to control the Arlobot? If you're using some sort of Propeller board, I hope you check out the Open Propeller Project #8. I've been having a lot of fun with my Arlo hardware.

ChrisL8

You can actually do whatever you want, but I think that the design is for the power board to be in the back.

In the end the only real difference is that negative speeds go one way, and positive the other.

Here is the wiring diagram I followed:
http://forums.parallax.com/showthread.php/152636-Run-ActivityBot-C-Code-in-the-Arlo!?p=1232417&viewfull=1#post1232417

It isn't pretty, but NikosG made it clear.

P.S. Note that according to the motor controller documentation here http://www.parallax.com/sites/default/files/downloads/29144-HB-25-Motor-Controller-V1.2.pdf
the red wire on the controller is NOT CONNECTED in the controller. In other words, it is 100% ignored, thus the jumper on the Propeller Activity Board is set to just send it unregulated 5V, because it is not being used, thus no need to mess with it.
The controller only uses the Black ground and White signal line.
And in fact, I'm just using two of these wires: https://www.adafruit.com/product/793 to connect from the Activity Board to each HB-25, so the red line in the "servo wire" is not even connected from my Activity Board to my HB-25's.

Duane Degn

ChrisL8 wrote: »

The controller only uses the Black ground and White signal line.

I'll add a note about the encoder power.

Only one of the two power (and ground) connections on the encoders is required (even when both data lines are used). The encoders will work with 3.3V power. When powered with 3.3V a resistor isn't required on the encoder data lines. You don't really need to worry about this if you're using the servo connections on Activity Board since the servo pins include a series resistor to keep the Propeller safe when powering the encoders with 5V.