Frequently Asked Questions

The simulator code uses the Tank.h library, which is designed to only run with the simulator. You will have to make your own motor controller code for your OTV to work.

The simulator does not support pointers.

Try to verify the arena coordinates your OTV is in and that you're asking it to turn to the correct angle. In addtion, add +- thresholds to target angle. For example, if you have a target angle of 90°, set a range between 85° and 95°. In addition, make sure that you are sampling the coordinates frequently enough. Try to sample the coordinates every 20 milliseconds in order to get a consistent update on your OTV location.

Try detaching the servo using the “servo.detach()” method. You should only have the servo “attached” (use servo.attach()) when the OTV is actually executing the mission. Before and after that, unless the servo is needed, it should be “detached”.

Check your code. If there is no apparent error, try adding an extra delay so that the system has enough time to fully process.

Isolate the code that you intend to use for the motor/sensor and place it in a new sketch. This can verify that your commands work and are pointing to the correct pins. If it does not work, verify that you have the correct pins and that the amount of voltage you predict to flow to a specific point is correct (view multimeter FAQ if necessary). Modify code and wiring as needed. If that also doesn’t work, try to reintegrate earlier parts of the loop to see if your code is getting stuck somewhere else. Rinse and repeat.

Consider lowering the threshold (or distance) at which the sensor is activated. This increases the relative sensitivity of the sensor.

Use pins 50, 51, 52, or 53 for Arduino Megas. Do not use pins 0 and 1 on your Arduino.

There could be many reasons why. First check to see if there is a red light on the wifi module. If there is, that means it is getting power (not necessarily the correct amount). If the red light is very dim, check to make sure that you’re giving the WiFi module 5V power (not 3.3V). If it’s still dim, your Arduino may be supplying too much current to other devices on your OTV so they should be powered from your battery instead.

If there isn’t a red light, check your circuit to see if any wires are disconnected or placed incorrectly. If that is corrected and there is still no red light, then use a multimeter to check to see if the wifi module is actually receiving the correct voltage of 5V.

Turn the multimeter to 20V (this is because the wifi module requires 5V and the voltage of the multimeter should be higher than that) and then put one probe on the ground source (the wire or port which the wifi module is connected to) for the wifi module and the other on the power source. Make sure the battery is connected, the kill switch is on, and the Arduino is not connected to a computer or power source other than the battery. The reading on the multimeter should be ~5V. If it is not, the wifi module is not receiving the correct amount of power. This means an error in the circuit.

If there isn’t a blue light, that means that the WiFi module is not communicating with the vision system. First, do not use pins 0 or 1 (despite them being labeled TX and RX); on most microcontrollers, any digital pin except 0 and 1 should work. If you are using an Arduino Mega, check to see that TX is in 50, 51, 52, or 53. If TX is not in one of those, switch that and change the code accordingly. If all these conditions are met and the blue light is still not blinking, the problem is likely in your code. Is the program only running once in the setup() function? Make sure that there is something in the setup that is not in loop and that there is something in both. You could also try running just the example code from the ENES100 library (found on the website) to check and see if the wifi module is working.

Grab a multimeter, from one of the cabinets in the lab, and turn the dial to “continuity”.

Place one probe on a power component of the circuit and one on a ground component of the circuit. Both probes must touch the metal part of the component. If the multimeter beeps, the power and ground must be touching somewhere.

Repeat the process on different power and ground wires until you locate the exact location of the short.

Step 0: Check the condition of the tip of the iron. If it is very black, replace the tip (an example of a bad tip is pictured below). This is done by unscrewing the black grip of the soldering iron and removing the tip. Select a new one and insert it back into the iron. Screw the grip back into place over it. Do NOT do this with the iron plugged in or if the iron is hot!

Step 1: Turn the soldering iron on to 450 F and wait until you see that the small number (green arrow) matches the larger one (red arrow)

Step 2: Make sure that the sponge under the iron is wet and that the fan for your iron is on

Step 3: Make sure your wire is set up correctly. Both wires you are soldering should have the ends stripped about 0.5 inches.

Step 4: Plunge the soldering iron tip into the tip tinner (pictured below). The tip tinner should bead up along the tip. After this, shove the entire tip into the steel wool (pictured below) and rotate it around. To remove any beads of solder but keep a thin layer behind. Then, use a brush to paint the flux onto your wires.

Step 5: To help ensure a strong solder connection, heat up the wires before begining soldering. To do this, touch the soldering iron tip to the wires and hold it there. It should take a few second for the wire to heat up. This will take longer for thicker gauge wire.

Once the wires are hot, unwind the solder (pictured below) and feed the solder into the section which you just preheated. If your wires have been preheated and you have both the solder and the iron in contact with the wire, the solder should melt, flow along twisted wires, and then cool.

Alternatively, for larger connections, after melting some solder onto the iron tip, touch the end of the solder to the wire connection and touch the iron to the same connection. Heating up the connection will melt the solder directly onto the connection.

Step 6: To test to see if the soldering job was done correctly: pull the wires apart. If they separate, try again. You can also check for connectivity with the multimeter (view Q: How do I find shorts in my circuit).

For if it’s the wrong size, make sure the dimensions are 1:1 when exporting from Fusion360. You should also make sure that the style in Fusion360 is “line”

Check for common ground! The H-Bridge and Arduino should be commonly grounded. If two components that have ground terminals aren't connected, they will be "communicating" at different voltage levels and will most likely not work.

pinMode() is already done within the ENES100 library. Doing pinMode() on the pins again can cause conflicts within the code.