The first day of any filming is usually a long day as
there are all sorts of shots to get to set-up the series.
I get up about 4.30 am and am ready with the rest of
the crew for a 5.30 am start. The series starts with
us Roughies flying into the new location in a helicopter.
What is strange about this first day is that the desert
is cool! Of course it is still early but it is surprising
that it is so cool.
Our challenges for this first programme are varied
and include finding water in the desert, purifying it
to drink and - my personal challenge - to build a remote
control ‘Mars Rover’ machine to explore
For this challenge they have given us quite a lot of
high-tech, though basic, household type equipment including
battery powered power tools, a guitar tuner and various
car type electrical parts and wires. I take one of the
drills apart to see how the speed control works and
to best understand how I might fix it in place and attach
it to the wheels I found on the mine tip.
My first design uses 3 small bicycle wheels; 2 driven
by modified electrical hand drills and the last wheel
fixed in place on the rear. The thing looks like a sort
of Reliant Robin but we have named it the Martian Tok-tok
in honour of those 3 wheeled taxis in the Far East.
The idea is that the device is to be powered using
the two motors from the power drills, with the wheels
being fixed in the chucks of the drills. When power
is applied to the drills they turn the wheels, moving
the rover. If both the drills are on then the rover
goes forward and reversing the motor connections will
make the rover go in reverse. By reversing one motor
wiring with respect to the other you can make the rover
steer left, or with opposite connections - right.
I have already found a problem with this design, though.
By reversing the power to the motors I have a simple
way of making the Rover change direction. The problem
is that as the power is adjusted to steer the vehicle
to the left or right, the rear wheel tends to pull sideways
when it's meant to be heading forward. It is especially
bad if the rover is going slowly and in fact the effect
brings the rover to a complete standstill. I hadn’t
thought about this problem – what we need is a
wheel that is free not only to go round but must also
be free to follow the steering like a caster on a piano
or the wheels on a trolley.
Good day – much progress.
The idea of the rover would be to use the machine to
navigate an assault course using only the remote control
facilities we could make ourselves. One last challenge
was that we could not see the Rover directly and that
they would give us a wireless radio camera that would
be fixed to the Rover so that it can send back pictures
from it – we have then to navigate using this
information from the live pictures!
There is a very simple but rather nice way to get the
thing to be controllably remotely. Firstly they gave
us two walki-talkies and a guitar tuner. The tuner has
5 LED’s that light when the correct note is played
near to it (it has a built in microphone). I intend
to take a wire from each of the lights and use this
little signal to drive a relay that controls the motors.
We can make use of what is called diode logic to program
each LED output with a particular function.
For example the first LED will make both wheels go
forward and so the rover will go forward. LED two will
make the left wheel go forward but at the same time
make the right wheel go backward – this should
make the rover go left. LED three will do the reverse
and make the rover go right. Finally LED four will make
both wheels go backward and so the rover will reverse.
No LED’s means there will be no signals and so
the rover motors are off and the vehicle motionless.