ScooterPuter Design Notes

Just the notes please....

Seeeduino Mega
I chose the Seeeduino Mega because I was concerned about how much I/O the base model had.  It turned out this was a great choice because the base model is really limited.


Compatible with Arduino shields.
Has tons more digital output/input lines
Easy to control more than one shield.
Has 4x memory (128k vs 32k)
Real application has a lot more code than “demo” app.

Even doing a simple project, like my remote/relay project, you run out of I/O.  With the mega there is so much I/O that its no problem.  Turns out that the extra PWM out really makes a difference.

Arduino's use PWM for any output, and also for periodic tasks.  If you want a "fine" control you have to tweak the PWM.  Since the PWM timers are also used for the delay, this quickly becomes a problem.

Not a problem with the Mega, it has more of everything.

Display Shield

Color LCD display

Comes with software

Just remapped pins (because its Shield #2) and it worked.

A lot of fairly difficult soldering (has a bunch of really fine pitched soldering).

But worked 1st time

Shield did not have pass-through (for stacking) but was kit, so it was easy to just use the right connectors.

http://www.nkcelectronics.com/rgb-lcd-shield-for-arduino-65k-color-k65.html

Proto Board

Comes with stacking sockets (some of which I used for other Shields)

Use proto board to remap pins to allow Relay Shield to stack on top of display shield.

Proto board also drove the external PWM amp

Used proto board for system simulator.

Motor PWM Amplifier

Used Robot Power 30a Simple-H PWM Amp

Robot Power specializes in PWM Amps for combat robots.  (These motors are similar in size to the 400w mobility motors).

400w motor, is 20a @ 20v

Board has two half bridges

Because Combat Robots reverse directions rapidly.

Relay Shield

Cheap and really isolates output.

Has limitation of slow switching (vs ssr)

Board layout not rigged for stacked shields

What's with this?  Relay board uses only most of the Digital I/O.  Have to de-solder the stacked pins (some 30 pins) and replace with sockets.  Also have to tie power to Arduino bus.

For so much time saving, its very cost effective.