Control a Robot With a RC Transmitter & Receiver

In this instructable we will walk through how to set up a traditional RC hobby Transmitter and Receiver with a RoboClaw motor controller to drive a robot around (such as ServoCity.com's Runt Rovers).

Step 1: Wire It Up.

Motors:
- If you have more than 1 motor per side: wire the motors on each side in parallel
- Connect the motor wires to the screw terminals on the RoboClaw Motor Controller as shown in the diagram
- Brushed DC motors are reversible. If one side is going not going in the direction you desire simply swap the + and - wires where it connects to the motor controller.
Receiver:
Connect the receiver to the RoboClaw as shown. The yellow wire goes towards the outer edge of the RoboClaw and towards the label (CH1 for example) on the receiver.
BEC:
Look on the motor controller for 2 pins labelled "LB-MB" and make sure they have a jumper across them. LB-MB stands for Logic Battery - Motor Battery. Using the jumper means that instead of connecting a separate battery to power the motor controller logic, you can use the same battery that is powering the motors. This is referred to as a BEC (Battery Eliminator Circuit).
Battery:
Get ready to connect the battery to the motor controller, but don't connect it just yet. Just about any small LiPo will do as long as it matches the voltage range of the motors and motor controller and has a high enough mAh rating to power the motors.
- Some Notes about LiPo (
  Lithium Polymer
  ) Batteries:
  - They have several different metrics they are rated by:
    - mAh (milliampere-hour): The larger the mAh rating the longer your bot will run. For a more detailed explanation see http://electronics.stackexchange.com/questions/792...
      Let's say you want to use something like this 610mAh battery for the Bogie which has 6 motors. Each motor will draw between 190mA (with no load) up to 250mA (max load). Multiply by 6 and you get a range of 1,140mA - 1,500mA being drawn by these motors. Since you can approximate run-time by dividing the battery's mAh by the load's mA with this battery and bot combination you would get between 24min up to 1hr 52min of run-time.
    - S (Series): This represents how many individual cells are connected in series. Since it is standard for each cell to be 3.7v a 2S battery will be 7.4v, while a 3s battery will be 11.1v and so on. Keep in mind that a fully charged LiPo cell will put out more like 4.2v each so after a charge you will really get more like 8.4v out of a 2s and 12.6v out of a 3s LiPo.
    - V (Volts): Often times LiPo batteries just list the S rather than the Volts since it can be determined by the S value. The more volts the faster the motors will turn.
    - C (Capacity): The maximum safe rate of discharge for your battery... a 1,000mAh battery with a 20C can handle 20 amp loads. See https://www.commonsenserc.com/page.php?page=c_ratings_explained.html for a nice explanation.
  - Never let your LiPo get down to or less than 3v per cell... this means if you are using a 2S LiPo you don't want to let it get down to 6v.
  - Always take care when charging LiPo batteries. Don't leave them unattended and put them in a fireproof bag or container while charging.

Step 2: Configuration

But First a Note about Channel Mixing:
The x and y axis of each joystick on the transmitter each has its own channel (that's why our 2 joystick transmitter has 4 channels). We will just be using the right joystick.

If we don't mix the channels then pushing the stick forward or back would drive one side of the robot and pushing the stick left and right would drive the other side of the bot. So we will want to mix channels 1 & 2 so pushing the stick forward drives both sides forward, pulling back will drive both channels backwards and pushing the stick left and right will steer the robot tank style.

There are 2 ways to go about channel mixing with this setup: either we can let the transmitter do the mixing or we can let the motor controller do the mixing. After some experimentation with both I found letting the motor controller do the mixing worked much better for driving a robot. This is because when I let the transmitter do the mixing (in what I refer to as "mixing mode B" below) moving the stick diagonally (top left, top right, bottom right, bottom left) does not drive the bot at all, this can be very disorienting if it is not the behavior that you are expecting. I presume the Tactic does this because it makes sense in the world of RC planes... I have come to the presumption because the user manual seems very RC plane biased (based on the nomenclature).

RoboClaw Motor Controller Settings:
You can change your RoboClaw settings either via the on-board momentary push buttons, or by plugging into a PC via a USB cable and using the IonMotion Setup Application but make sure you've first installed the USB Roboclaw Windows Driver.

For now I'll assuming you are using the on-board buttons. You can change the Mode, Option and Battery settings.

Click MODE, or SET, or LIPO to enter Mode Setup, Option Setup, or Battery Setup respectively.

Regardless of which setup you have entered the STAT2 light will begin blinking to tell you which setting you currently have selected.

While you are in one of the 3 setups, the SET and MODE buttons will increment and decrement the setting respectively. Clicking the LIPO button will apply the setting and exit the setup.

You want Mode 2 (RC Mode with Mixing) and an appropriate battery setting.

Power on the RoboClaw
Set the mode to RC Mode with Mixing (mode 2):
1. Click the MODE button
2. Click MODE or SET until you get blinking pattern of: (2 fast blinks, pause, repeat).
3. Click LIPO to save your changes and exit the setup
Set the battery setting to match your battery, let's pretend you are using a 3S LiPo:
1. Click the LIPO button
2. Click the MODE or SET buttons until you get a blinking pattern of: (4 fast blinks, pause, repeat).
3. Click the LIPO button to exit setup
Power off the RoboClaw

We don't need to set an Option in our case, but the process is the same.

You can learn more about all of these settings in the RoboClaw user manual.

Tactic TTX410 Transmitter Settings:
Out of the box the Tactic TTX410 transmitter is not configured to mix the channels. As I mentioned above we want to leave it this way. However there are different channel mixing modes on the Tactic TTX410 and if you hear more than 1 beep when you turn it on then you are using channel mixing on the transmitter and will need to know how to turn it off.

To change/disable the mixing mode:

With the Transmitter power switch off, move the right stick to the bottom-right corner, the left stick to the bottom-left corner, and hold in these positions.
Turn the Transmitter power switch on. You will hear a series of beeps (you can now let go of the joysticks). If the number of beeps your ears perceived is not equal to what you desire, turn it off and do it again.
1 beep = no mixing
2 beeps = mixing mode A (mixes left stick X axis and right stick Y axis)
3 beeps = mixing mode B (mixes right stick X & Y axis)

For More information see the Tactic TTX410 User Manual.

Step 3: Test It Out

Turn on the transmitter, then supply power to the motor controller and test it out!

REMEMBER TO ALWAYS TURN THE TRANSMITTER ON FIRST.
The RoboClaw will take about a second to calibrate neutral position based on the signal it is receiving from the transmitter.

If one or both sides are travelling in the opposite direction from what you want you can do one of two things:

You can swap the red and black motor leads where they connect to the speed controller.
Or you can flip the appropriate dip switch on the transmitter. On the Tactic TTX410 System I used you can access the dip switches by switching the battery panel, channel 1 can be inverted by dip switch 1 and so forth.