Keith has been working with a tool called “Fusion360” to create the 3d models for our robot. This can then create the 3d printing file as well as laser cutter instructions. However – one other feature is that it allows you to create an animation of the 3d object!
Keith has been doing some more model work in Fusion360 (not on the cat walk!) So far he has the guts of the Nerf gun launch system and magazine modelled, and work has started on the mount system. Over the next few weeks hopefully he will get this finished and we can get the parts cut and printed and trial fit them to the bot.
Last week Phil was playing around with object tracking. So far he can identify colour objects and track the centre. Phil produced a quick video showing how a red skittle (from last years PiWars skittles challenge) can be tracked and traced on screen. This looks like a good start, now just need to get the robot to follow it.
Keith has been playing about with a new cheap power supply using the Nerf Gun motors as a test bed. It turns out power supplies are quite a good method for determining how much current they draw and thus what current the motor driver needs to deal with. Keith produced a quick video demonstrating the power supply with examples using the Nerf Gun motors.
If you are still deciding on motor drivers he recommends getting the motors first and doing a simple stall test with a power supply or multimeter and then getting the motor driver to suit.
The first challenge the team want to tackle is “The Duck Shoot” as this is new to this years event. The challenge involves shooting five targets down over three attempts.
Since the rules allow Nerf darts to be used, Phil went out a procured a nice looking, powerful gun!
The Strip down!
The only bit we need of the gun however is the dart holder and the firing mechanism. So the team set to work stripping this down and designing a robot mount that means we can add and remove the challenge components as we go.
One thing we need to be careful about, is power. If the device needs too much power we will need to change batteries too often, to little and we could miss the target. So to ensure that this is calculated, we need to test the power requirements.
In true maker spirit Keith brought a Bench power supply kit from eBay and tested the requirements of the Nerf motor
Bench testing the Gun
Motors pull 1.9A on spin up and then drop to 500mA. With my
New power supply I can limit to 600mA and it spins up nicely. I’ll have to see how I can do that in hardware to be kind to our Pi
So thew challenge here for us is to design a circuit to limit the power consumption of the motors.
Hopefully with the experts we have in the team, a nice tiny circuit will be designed that will help with the power.🤞