With the rebuild complete, we can finally move on to fine tuning the code for the events. John had a great weekend here, with working code for the proximity alert.
The robot uses optical sensors to spot the wall – we’re using A to D converters on the Arduino to read the amount of reflected IR light. Away from the wall, virtually no light is reflected. As you get closer, the reflection gets brighter. The trick is to decide at what level you should stop. We have multiple sensors on the front so that if the robot doesn’t approach the wall perfectly straight on, one of the side sensors will still spot the wall and stop us before collision.
The next task in the tuning will be to test many times and against different types of wall – that’ll tell us what sort of repeat-ability we have – which will be key to getting a good result on the day.
So what should you never do in the run up to a competition? Throw away your robot and start again. But that’s (almost) what we’ve done…
So the old robot chassis was always intended to be temporary – made of 3mm cardboard and aluminium brackets. We finally got round to replacing it with a chassis made of 5mm PVC foamboard cut on a CNC router. But it means a tedious task of removing all the parts from the old chassis, bolting them on the new and re-routing all the wires.
We’ll see shortly if we’ve managed to do that without error…
John and I had a session last week trying to get the line following sensors to produce the results we expected. To cut a long story short, we ended up putting blinkers on the sensors which seems to have made all the difference.
John then went away and put together some line following software – and it seems to work. There might be a bit of tuning to be done and some alterations to the calibration code, but it does seem to get round a test course: