HOWTO - Parts
This is a basic guide on howto build an antweight and will hopefully
turn a pile of parts into a deadly fighting machine.
When building an ant there is one main goal, <150g. This may sound
easy and is if you have no weapon, however the weapon can add 60g taking
the ant overweight. And even if it's 149g on your scales it maybe 152
on battle day, it happens.
The next bit will explain the basic components of an ant:
Drive, to drive an ant the most popular was is to use micro
servo's and modify them for 360 degree rotation (they normally only
rotate 90 degrees). Other methods of drive have included slotcar
motors with speed controllers.
Modification isn't too hard if you have build model kits and have
a steady hand.
Modification won't be mentioned here, the principle is the same
and two descriptions can be found below:
Batteries, these can take up the majority of the 150g limit
if your not careful. There are only two choices until I get corrected,
NiCad (Nickel-Cadmium) or NiMh (Nickel-Metal Hydride). NiMh are
very slightly more expensive but contain a higher charge rating
(Ah, Amp hours, or in out case mAh. milli Amp hours).
For an ant without a weapon or low drain weapon 100mAh batteries
can be used, typically 4 cells are minimum (4*1.2V=4.8V) although
depending on the weight of the ant it can go upto 6 cells, 7.2V.
For spinning related weapons 300mAh is really the minimum value
you should look at.
For batteries I highly recommend Overlander.co.uk
Receiver, (Rx). Although the ant rules allow IR (infra-red)
and other exotic control types, normal remote control is the most
available way of controlling an ant. Unlike Robot Wars antweight
rules allow 27, 35 (not preferred), 40Mhz and higher. This allows
existing RC (Remote Control) equipment to be used reducing the cost
of building an ant.
Normal Rx's can typically weight 40g, pictured is a Hitec feather
receiver weighing approx 10g without crystal (another gram). This
lost 30g can allow a weapon to be added.
Mixer, not vital but nice if you have £13 and 5g spare
on your ant, the details of a mixer can be found below.
Shown is a GWS mixer.
As already mentioned modified servo's are normally used to drive an ant.
If servo's are being used the type of drive is called 'independant drive'
or tank drive, this means both wheels are being driven independantly.
As a contrast RC cars have 1 drive motor and a servo controlling the steering,
the bad point of this is the turning circle. With independant drive the
turning circle is 0, turning on a coin is possible.
Now for that mixer explanation.
This is how a basic ant would be driven, the Rx is connected to
the drive servos.
This means on the transmitter (Tx) you need 2 sticks, one goes
forward and back and the other goes forward and back. Not many Tx
do this and if it does it normally has a ratchet on one channel
so it won't return to 0 when the stick is let go.
For a RC car Tx this can be very confusing. You have to either
swap one of the sticks round on the Tx so it goes forward-back or
you have to learn to drive so left-right goes back-forward.
By including a mixer driving is made easier. The mixer takes the
2 forward-back channels and 'mixes' then into a forward-back and
So on the Tx when you press forward on the stick the ant goes forward
and the same with reverse.
When you go left the clever bit kicks in as one motor goes clockwise
and the other goes anti-clockwise so the ants spins on the spot.
This is very good if you have a RC car remote as it will control
an ant without modification or confusion.
The only bad point about mixers is if you push forward 100% and
turn it won't turn as you expect due to the way the mixer handles
the inputs. You have to decrease the 'throttle' to say 80% and turn,
this will allow the ant to turn as you want.
Now, an idea