Here's the Swordfish
BASIC Mongoose module (beta
0.9) it works great but I'd like to add the tachometer module too.
Currently the modules sole subroutine is
MotorLR(+-127,+-127)which
will drive the Left and Right motors. Sample code shown below.
Device
= 18F2525
//
Mongoose CPU PIC18F2525
Clock = 8 // 8MHz
Include
"Mongoose.bas"
While true
MotorLR(64,-127) // Left
fwd 64 (50%), Right rev -127 (100%)
High(PORTC.0)
// turn on the headlight LED
DelayMS(5000)
// delay 5 seconds
Low(PORTC.0)
// turn off the headlight LED
MotorLR(0,0)
// stop
DelayMS(1000)
// delay 1 second
Wend
// repeat
End
The first production
run of the Mongoose kits are ready, the black anodized frame
halves look and fit great. I've posted a couple of photos to show
the front and underside view of the first assembled kit notice
the ball caster. I've been working on some demo code in both
assembler and SwordfishSE BASIC I'll be posting it here ASAP. Note:
Mongoose does not get its power from the ICD2 but relies on the NiMH
batteries for both motor & CPU power. Do not use an unregulated
power supply in place of the 4xAA batteries as this will damage the
PIC. A 5V 2A switch mode regulated adapter will work fine. The
ferrite bead at J1 can be replaced by a simple wire link if desired.
The SN754410 runs only warm so the heat sink in the drawings is not
necessary. All that we're waiting for is the new chassis metalwork
and anodizing to be done.
The manual is
currently a work in progress but I won't make you wait if you can't
wait to get your hands on the kit ASAP. The manual will be updated
and available free online with the first release having the BOM,
schematic and a few diagrams like the one on the left to get you
started. When building the PCB you'll have to pay attention to the
build order and the part location as parts mount on both sides of
the board.
The Mongoose is well
balanced and stable, at full speed the wheels turn about 120RPM this
translates to about 0.36 meters per second. Having the rotation
sensors as standard equipment (usually an expensive option on small
robot kits) you can slow the Mongoose down to a crawl and even get
an idea on how far its traveled.
The optical
interrupter gears (the blue one with the three black stripes) are
easy to paint with a Sharpie fine tip paint marker. If you're
skilled enough you can add more stripes to increase rotation sensing
resolution. The interrupter gears turn 27x faster than the wheels,
so two or three stripes represent either 108 or 162 light to dark or
dark to light transitions per wheel rotation. Higher resolution is
possible but for ease of assembly we'll be choosing from either two
or three stripes as the recommend standard.
On he top right is a
pin connector designed for a pair of optional servo motors. The pair
of inline connectors contain access to all the unused pins on the
18F2525. A single white LED is on the right side and a single 10K pot
on the left (when viewed from the front).
13mm standoffs on the front
are for user boards (example a line follower PCB or sonar PCB).
The Inchworm ICD2 connector
is on top.
Here's an early
release of the
Mongoose
Assembly manual.
