[Dprglist] Rayo Pinky-Pie 7.0

Eric Yundt eric at facetcorp.com
Thu Aug 9 00:10:03 PDT 2018


Okay, we are officially mobile now!

I wired a 7.4v LiPo to our step-down DC-DC converter set to output 5v and
then sent that on to VMOT of the TB6612FNG H-bridge.  A little pin
connecting later and some simple code driving some pins high, others low,
plus PWM, and Rayo Pinky-Pie was ready to show off his paces:  Forward,
Reverse, Turn CW, Turn CCW.  Nothing exploded!  Nothing let the smoke out!

We have yet to count encoder ticks, or attempt to read a line with our
QTR-8RC reflectance array, nor hook up our Sharp GP2 (10-80cm) IR sensor or
the TCS3200 color sensor, but Rayo Pinky-Pie is coming together very
nicely.  Real soon now we're going to be ready to bring all of our
peripherals together in one big control loop.  Plus we need an actual
ON/OFF switch.  The DC-DC converter has an ON/OFF switch, but I haven't
wired anything inline with the UNO battery pack yet.

Too much fun, we are having!  ;-)


On Tue, Aug 7, 2018 at 1:24 AM, Eric Yundt <eric at facetcorp.com> wrote:

> Progress!  Last night we had a chance to neatly mount some stuff.  We're
> using a pair of "TT" gear motors and one of the common "Smart Car" acrylic
> bases on which to mount things -- so far:
>     Arduino UNO
>     2 x 7.4v LiPo 1000mAh (1 direct for UNO & Sensors, 1 via DC-DC
> converter for motors)
>     2 x 6v "TT" gear motors 1:48
>     2 x 20 slot shaft encoders
>     2 x Waveshare foto interrupters
>     DFRobot 25W Step-down DC-DC converter (for 7.4v LiPo to 6v for motors)
>     Hitec HS-422 servo motor (for sweeping sonar range finder)
>     HC-SR04 ultrasonic range finder
>     Pololu TB6612FNG dual H-bridge
> Still to mount:
>     Pololu QTR-8RC reflectance array
>     TCS3200 color sensor
> Finally our 1st good WOW!!! moment with the fam...  ;-)  We wired up the
> foto interruptors and the sonar servo motor and I loaded up a servo sweep
> program, then let'r rip!  Our foto interrupters have some nice red and
> green LED's that blink with encoder disk readings.  The servo motor did
> nothing but hold the sonar sensor up high and sweep back and forth, but
> that made for real showy flashing lights, and moving the Robot "head"
> around showed the family we actually could drive a motor with our little
> Robot brain.  Rayo Pinky-Pie has officially been declared alive by all who
> were there for our 1st real show-and-tell.  Our 7-year old remembered our
> favorite 2 animals (dolphins & bats) that get around using similar sonar
> echo object detection and explained how echos work to mama and grandma both.
> I got a chance to troubleshoot and overcome our 1st real challenge --
> program upload errors.  Of course we never hit this when playing with the
> Arduino and a few things on a breadboard.  Finally I narrowed it down to
> the shaft encoder signals interfering with the USB Tx/Rx.  We've got them
> hooked to D0 & D1 of the Arduino for the external interrupt capability.
> Those 2 pins also double as Tx/Rx pins used for the USB program loader.
> When that finally clicked, we disconnected the foto interrupter signal
> wires and were able to successfully upload a program to the UNO.
> I think tomorrow we'll be able to wire up our DC-DC step-down converter,
> the H-bridge, and put the juice to our drive motors.  Actually driving
> around while waving the sonar back and forth will be our next big WOW!!!
> waypoint on our journey into Robotics.
> BTW, having comm errors with our Arduino was enough to scare me into
> buying a spare UNO and the bigger brain (ATmega2560).  I found an in
> country distributor of Arduino, Adafruit, and Sparkfun products and
> shockingly the prices were not all that horrible!  Genuine UNO Rev 3 for
> $21.95 USD, Generic UNO R3 with USB cable for $7.95, Generic MEGA 2560 Rev
> 3 for $18.95.
> Time to start planning our software approach...  Yay!!!
> --
> Eric
> On Sat, Aug 4, 2018 at 7:23 AM, Eric Yundt <eric at facetcorp.com> wrote:
>> I stunned and amazed at how easy working with the Arduino UNO is.
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