Antweight Drive Kit Build Guide

Any issues or questions during the build, you can email us at bristolbotbuilders@gmail.com or message us on facebook, we’ll be happy to help.
As well as the included parts in the antweight kit you’ll need the following parts (we’ve linked some suggested ones):

Tools you will need:

  • Soldering Iron
  • Solder
  • Wire cutters/strippers
  • Heat shrink or electrical tape
  • Cross head screwdriver
  • Optional: Scissors, drill, hacksaw for making a polycarbonate chassis

Once we’ve soldered and plugged everything in, we’re aiming for a circuit that looks something like this:

Here it is in diagram form thanks to Team DSC!

So let’s get started!

1. Solder the Motors

The BBB Dual ESC comes with the connectors pre-soldered, but we still need to solder the N20 drive motors.
Firstly cut off the circled two black connectors , these are the motor outputs. You can shorten the wire a bit if you like to save a bit of weight and space.

When soldering check the back of the motors – look for the little plus symbol by one of the N20 motor tabs (see image below) – it’s worth soldering this side’s tab to the ESC’s motor output red wires on both N20s – this means they’ll spin the same direction when we want them to!

Strip a bit of wire insulation off the end of each of the four wires and solder each pair of red and black wires to the tabs on the N20 motors – make sure it’s the correct two wires per motor – one pair is labelled M1 and the other M2 on the circuit board.

2. Solder the Switch

This is optional but it’s good practice to have a method for turning your robot on or off apart from unplugging the battery. It’s only a requirement to have a switch if your antweight has a spinning weapon. Firstly cut the circled red wire but leave the black wire as is.

Strip a bit of wire insulation off each side of the red wire and solder one end to an outer pin and the other end to the middle pin of the switch. Use heat shrink or electrical tape to cover the pins and exposed wire.

3. Transmitter

For robot combat we typically use a ‘mode 2’ transmitter, which means the stick directions are labelled the following:

If you’ve got a mode 1 transmitter the only difference is the Throttle and Elevator sticks are swapped.
In Robot Combat the typical transmitter setup is using:

  • Elevator (up/down on right stick) for robot’s drive forwards/backwards
  • Aileron (left/right on right stick) for robot’s drive left/right
  • Throttle (up/down on left stick) for robot’s weapon control.

You can set up to drive your robot however you like, but we’ll use this layout in this guide.

Turn on the transmitter and select the model slot you want to use for this receiver / bot by doing the following
(for FS-i6, check your manual for your transmitter):

  1. Press and hold OK button to see System Setup Menu. Press OK button.
  2. Press UP/DOWN buttons to select Model Select and press OK button.
  3. Press UP/DOWN buttons to select the model you want to use.
  4. Press and hold CANCEL button to load model.
  5. Now turn off transmitter.

4. Receiver

When your receiver and transmitter are connected if you press up on the elevator stick of the transmitter, the receiver will send that signal out of the elevator pin.
You’ll need to find the following pins on your receiver:

  • positive (+ve) – usually red wires
  • ground (GND) – usually brown or black wires
  • signals (PWM) – usually yellow, green or white wires.
    4 signals we typically use on receivers that match up to the sticks on the transmitter diagram (above):
    • Throttle (THR)
    • Aileron (AIL)
    • Elevator (ELE)
    • Rudder (RUD)

Here’s the pinout for the receiver that can be included in the kit:

Please note: With the Flysky FS2A receiver you can either chop off the motor servo connectors below and solder the wires directly to the pinholes – we like this method for space saving and less soldering! – or you can solder the included receiver pins on to the receiver (picture below) and plug in the servo connectors.

FS2A 4CH AFHDS 2A Mini Compatible Receiver PWM Output for Flysky ...

5. Connecting the Dual ESC to the receiver

Circled are ‘servo connectors’ which connect the the Dual ESC signal inputs to the receiver as well as provide the receiver with power (using the Dual ESC’s built in BEC – this reduces your 2S lipo voltage (8.4V at max) to 5V to protect the receiver and low powered servos from damage)

  • On one servo connector:
    • white wire drives left/right on the motors
    • red wire provides the positive rail of the BEC at 5V (+VE)
    • black wire provides ground (GND)
  • Separate yellow connector: drives forwards/backwards on the motors.

In this picture we have how we’d connect up the flysky receiver:

  • white wire (left/right on the motors) plugged in to channel 1 of the flysky receiver which by default on a FlySky FS-i6 transmitter is left/right on the right stick (AIL) On the same connector the red wire connects to +VE and black wire to GND (as the BEC) powering our receiver.
  • yellow wire (forwards/backwards on the motors) plugged in to channel 2 which is up/down on the right stick (ELE) .

Double check you’ve connected your receiver up correctly, each brand will have a different layout – you want white wire to AIL, red to postive, black to ground and yellow wire to ELE.

6. Binding the receiver

Firstly plug your lipo into the JST connector (red) circled below, then follow the instructions to bind your receiver.

This is specific to our flysky receiver with a FS-i6 Transmitter , follow the manual for yours if you have a different one.

  1. Hold down the bind button on the receiver whilst turning it on with the switch. The blue light should be flashing rapidly, meaning it’s in bind mode.
  2. Hold down the bind button on the transmitter while turning it on. You will see ‘binding’ on the screen
  3. When the receiver is flashing slowly turn the transmitter off and on again.
  4. You should see the blue light on the receiver go solid.
  5. Now if you move the right stick up/down left/right the motors should move. You have bound the receiver to the transmitter! If not check through the instructions again. Switch off the circuit.

If all has gone to plan you have bound your receiver to your transmitter! You can now waggle the right stick and you should see both motors moving. If one or neither are moving then double check your connections with the steps above.

7. Failsafing

Failsafing is when your transmitter is turned off your robot’s drive and weapon will stop. This is an important safety feature. Check the manual for your transmitter and receiver if you don’t have the following set up.
Failsafing on Flysky FS2A receiver (July 2022 and newer models – see below for how to check):
You can set the failsafe on the transmitter – you must set each channel individually. Example for FS-i6:
Good video here. With your robot on, go to Menu > System Menu > RX setup > Failsafe
Turn on failsafes for the channels you need – in this example: Channel 1 & 2 for drive are set near middle and Channel 3 in this case is set low for spin up on throttle. Once you’ve set them up hold down CANCEL button to save. Test your failsafes are working (turn off transmitter)
The “all channels” failsafe in the menu will not work for this receiver.

Failsafing on Flysky FS2A receiver (pre July 2022 models – see below for how to check):

  1. Turn on both your receiver and transmitter.
  2. Set your transmitter’s right stick to the middle and push the left stick to the bottom.
  3. Hold the bind button on the receiver, the blue light will flash quickly several times then go solid. Note: this is just the failsafe for this model of receiver, if you have a different one, failsafe setup may be different. There’s a failsafe option in the transmitter menu too.

New and old versions of flysky receiver
New style have a larger square chip vs smaller rectangular on old (pictured)

8. Build a basic chassis!

At this point it’s a good time to build a chassis – first attach the wheels and motor mounts to the motors.

If you’ve ordered some polycarbonate sheet, you can make a chassis like below. Alternatively many antweights are 3D printed – if you own a 3D printer or can access one (schools, universities, local libraries and hackspaces are a good place to check) you can print out a chassis! There’s lots of examples on thingiverse (make sure they’re ones that are UK sized – 150g in weight. American ones are 1lb) but you can also design one using CAD software!

If you have some polycarbonate, cut a baseplate out of the sheet using scissors. Make holes in the polycarbonate for the mounting points. Screw the motor mounts down into the polycarbonate. Then add some sides, and maybe a wedge! Cable ties and small screws and nuts (M2, M3) are your friend! Something like this chassis below by Harry is a good place to start:

9. Adjusting the drive on the transmitter

Now you’ve got a platform to test the drive! Does the right stick drive the robot as you’d expect? If not here’s some things to check:

  • Is forwards on the stick turning the robot left or right instead?
    • Then check your receiver connections – you’ve probably got ELE and AIL the wrong way round
  • Is left on the stick dring the robot forwards or backwards instead?
    • Then check your receiver connections – you’ve probably got ELE and AIL the wrong way round
  • Is forwards on the stick driving the robot backwards?
    • You want to reverse Elevon:
      • Hold OK, press DOWN and then OK to select FUNCTIONS SETUP
      • Press OK to select REVERSE
      • Press OK to select CH2 (ELE) and press UP to reverse it.
      • Hold down CANCEL button to save.
  • If left on the stick turning the robot right?
    • You want to reverse Aileron:
      • Hold OK, press DOWN and then OK to select FUNCTIONS SETUP
      • Press OK to select REVERSE
      • Make sure you’ve got CH 1 selected (AIL) and press UP to reverse it.
      • Hold down CANCEL button to save.

Hopefully after this you’ve got a driving robot – with the stick behaving as you’d expect!

10. Adding a weapon!

If you’ve picked up a servo, this can be plugged straight into the receiver. We want to use throttle (left stick up / down) for the weapon, so on the flysky receiver we’d plug it in to channel 3, making sure black goes to ground, red to positive, and yellow/white to signal, same as the ESC.

If you test out this with the power on you can see that up/down on the left stick of your transmitter will move the servo from one end of it’s travel to the other.

That’s pretty much all the steps to making a driving chassis! Any questions please email us at bristolbotbuilders@gmail.com or post in the facebook group!

Thanks for reading 🙂
– Joe