25th Jan 2017
Before we go any further lets agree to keep any costs between us. I wouldn’t want my family knowing exactly what I’ve spent on my hobbies instead of holidays 😉
So with that out of the way, the basic drive-train has been decided and building started so next we need to focus on some of the challenges. Golf first as it has peeked our teams interest for most comical effect. Amusingly the photo above actually shows us doing first feasibility tests on using an arm mounted putter on a cheap lightweight servo. When I say putter, I actually mean metal ring with a pencil stuck to it 🙂
I can’t believe how many ‘unlikely to succeed’ ball moving suggestions we have gone through on the golf challenge. It started with the simple yet effective servo mounted putter pausing slightly with a variable power solenoid kicker and ended with gas powered combustion ball launcher. Seriously, someone (probably me) actually thought it might be funny to “fire” the ball….not a good idea, not power adjustable between shots and DEFINITELY not guaranteed to keep the ball touching the ground at all times.
Still, we haven’t actually settled on the putter idea as the solenoid one keeps rearing its little head because it seems ‘simpler’ and ‘less prone to mechanical failure’. On testing the metal putter idea above it was quickly noticed that any competing solenoid idea would either have to have a reasonable mass on the moving arm or be extremely powerful to have any chance of moving the ball any distance. Then comes the adjustable power problem….so, so far the putter is winning.
The first round of tests were done using an Arduino Mega the team member writing the test code to make a servo move had one to hand, but obviously we won’t have room for such luxury in our bot so the second round of testing will be done on the Arduino Nano, shown with a carefully placed Raspberry Pi NOIR camera in shot. The reason for using Arduino’s to control the servo is basically PWM timing accuracy. Obviously the Raspberry Pi will be in control of the whole system and will tell the Arduino exactly what to do at any point, but why not sub-out some of the low level work to devices that are designed to do this kind of thing day in and day out. That said, the Arduino will also be used for multiple things in combination with the Pi. One such task will be analog to digital conversion as the Pi has no analog GPIO pins and a Nano is a very cheap way to incorporate this feature.
Now that the drive-train design has settled down, we thought it wise to buy spares of everything. 8x motors, 8x motor controllers (ESC’s) and lots and lots of connectors and wire. Last year we went through soooooo many cheap ESC’s. Since then we have found a decent supplier, albeit from Australia, and have stocked up. Plus it made the delivery cost more efficient, well that is what I’m telling my wife.
Well, onward we go and always attempting to avoid the bunkers 😉