Analog to digital, How Sound Is Recorded.

An Example of what a waveform looks like

Sound is an integral part of our lives, whether we realize it or not, and none of the recorded sounds we hear would be possible without two devices: an ADC(Analog to digital converter) and a DAC(digital to analog converter). And ADC is responsible for taking the vibrations of sound around us and storing them in digital form. A DAC does the opposite and converts the 0s and 1s of the stored sound’s data into the vibrations that our ears translate to sound. Before you can understand how either of these devices work, you need to understand how sounds are made. When a sound is generated, air molecules compress (get closer together) and rarefact (get farther away from each other). The series of compressions and rarefactions is what makes up the waveform and what our ears pick up and translate to sound. An ADC works by taking a measurement of the voltage of a sound a certain point in the sound This measurement is called a sample. The ADC takes tens of thousands of samples per second and  the higher this sampling rate is, the more detailed and accurate the recorded information is. An example of a sampling rate is 44.1k Hz. This means that the computer takes 44,100 samples per second. For each sample, the ADC computer measure the voltage at that specific point and stores that voltage as a binary number. The millions of binary measurements which make up a 3 minute recorded sound (just an example) is given to the main hard drive to save. A DAC is used when we want to listen to the sound we recorded. It does the opposite of a ADC and reads these binary voltage samples and tells whatever speaker you use what frequency and intensity to move its drivers. The drivers move back and forth and create the compressions and rarefactions our ears can detect.


Sources:
http://cloudinary.com/blog/how_to_generate_waveform_images_from_audio_files
http://www.hardwaresecrets.com/how-analog-to-digital-converter-adc-works/2/

How Robotics is Changing the Operating Room

Surgery is one of the most common medical procedures and It saves millions of lives a year. But not all types of surgery are created equal. Surgeries on major organs like the heart or brain are incredibly risky and difficult for doctors to perform, but a new form of robotics could be changing that. Robots in operating rooms are still a rare sight, but a few hospitals in the United States have started using them with promising results.

          There are several kinds of robots for surgery but the one I will focus on is called a supervisory-controlled robot. Instead of a doctor making incisions and stiches, the robot performs these surgeries with the instruction of a nearby doctor. Based on what kind of surgery is required, a doctor gives inputs to the robot, which then executes a preinstalled series of movements and actions to perform the surgery. The robot is not an AI system- it can’t make adjustments to its actions to prevent something from going on so a doctor still has to be in the operating room watching to make sure everything goes smoothly. Even though this input and output system seems basic, it has a couple significant benefits to the patient. The big benefit of using these robots is to cut out any human error that could occur. The machine is much more sensitive and precise than any human could be and so it is able to make smaller incisions to complete the surgery. This leads to a shorter surgery which greatly decreases the chance of any complications, as well as the recovery time for the patient. Even though none of the surgical robots in use can perform a surgery autonomously, they can provide a safer surgical environment and they will only become more advanced in the future.

Sources:

http://health.howstuffworks.com/medicine/modern-technology/robotic-surgery2.htm

https://www.unitypoint.org/cedarrapids/services-st-lukes-da-vinci-robotic-technology.aspx

http://www.intuitivesurgical.com/company/media/videos/systems/xi-overview.html

https://www.google.com/search?espv=2&biw=1218&bih=646&tbm=isch&sa=1&q=supervisory+controlled+robotic+surgery&oq=supervisory+controlled+&gs_l=img.3.0.0i24k1.53052.56567.0.57763.23.19.0.4.4.0.110.1301.17j1.18.0....0...1c.1.64.img..1.22.1307...0j0i67k1j0i5i30k1j0i8i30k1.Pt1REA-MRvE#imgrc=KC0-uwSp2VHKbM%3A

How VR Systems Create an Immersive World

       Virtual reality is arguably the biggest technology to emerge in 2015 and 2016. With the introduction of devices like oculus rift, HTC Vive, play station VR, and several others, virtual reality is becoming a mainstream technology. The way these systems work is with headsets, which we wear like goggles, that project an image to give the illusion of a three dimensional world. These virtual reality systems need several 

a photo of Googles "Daydream" VR headset which    

uses a cellphone to do its processing

things to work: the headset, a form of input, and a computing device. Similar to how a normal computer processes information, these systems take an input, use a computer to process that input, and then output the change to the virtual world by changing the perspective in the image. Most if not all virtual reality headsets have gyroscopes and accelerometer build in which monitor any head movements you might make. This is where the computing device matters most. When you turn your head for example, the headset uses these sensors to detect how far you turned your head. This information is sent to the computer which maps and then outputs the change in perspective to the headset-giving the illusion that the virtual world around you moved with your head. One of the keys to making this illusion work is having low latency, or lag. The illusion only works if the delay between when you move your head and when the world around you moves is kept to a minimum. If the latency is any higher than 50 milliseconds we notice the lag and it removes us from the immersion. In order to have lower latency you need more processing power, which is why minimum system requirements for virtual reality systems are very high. However as virtual reality becomes more and more mainstream we will undoubtedly see more accessible virtual reality. Cell phones are a promising use for virtual reality and already there are several basic vr systems that use cell phones.

Sources:

http://www.wareable.com/vr/how-does-vr-work-explained

http://time.com/3987022/why-virtual-reality-is-about-to-change-the-world/?pcd=hp-magmod

https://canaltech.com.br/noticia/google/google-apresenta-seu-oculos-de-realidade-virtual-daydream-view-81513/