We didn’t have the right URL, to get into dronesonenens website, so this post is a bit late.

The parts we ordered have been delayed, therefore we spent this week testing different arduino objects that we might need.

Servo

We tested a servo engine connected to arduino to use for our trigger system. 

Figure 1: Servo engine and button

The system works so that when you push the button, the servo engine will trigger the trigger on the pellet gun. We are however concerned that the servo used here does not have enough power to actually push in the trigger.

We tested if the MicroServo SG90 was powerful enough to press the trigger, and it was not. So we will need to use a more powerful servo engine.

Ultrasonic sensor

As mentioned above, most of our parts is delayed, so we are using our time now to test the parts we have at school. 

We got the ultrasonic sensors to work and we are planning to use them for automatic driving. It emits an ultrasound at 40 000 Hz which travels through the air and if there is an object or obstacle on its path It will bounce back to the module.

Fig. 2: Overview of how the sensor works

We will use three sensors. They’ll be placed on the front and on both sides. The side ones will be mounted on 45º with the symmetry axis. With that distribution we can prevent all possible obstacles. The next figure shows the electronic schematic.

Fig. 3: Electronic schematic and connections to Arduino

According with the previous connections, we’ve implemented the Arduino code. In general terms, the program makes the sensors generate a sound and later process the return of it. We do the previous sequence following the protocol of the sensor and giving the instructions needed.

After the hardware and software implementations ready we can make some test. But before, we only could test the two side sensors because in the school we only found two. It’s for this reason that in the measure “DistanceFront” all the time we are going to see a 0 (Nothing Connected).

The first test was by the left side zone. We were moving and approaching the obstacle from A to B but only in the left sensor range. The following figures show the read values by the sensor.  

Fig. 4: Obstacle and sensor response in position A in the left side

Fig. 5: Obstacle and sensor response in position B in the left side

The second test was by the front zone. We were moving and approaching the obstacle from A to B but now in all the sensors range. The following figures show the read values by the sensors.

Fig. 6: Obstacle and sensor response in position A

Fig. 7: Obstacle and sensor response in position B

To conclude, we verify the correct running of the sensors. We consider the ultrasonic step done and we’re ready for the next one. What is synchronize the two motors according with the ultrasonic data. We’re going to fix a threshold in the distance and then make the motors turn in the correct direction. However, we found that we could have problems with the sensors range. Therefor we’re going to find the perfect orientation and place for it.