Week 3 - Software & Electronic - Camera parts & Exit Sign

      According to the demand, we need to use at least 4 cameras in the room. Since puzzles need to make the room dark, our camera needs to have the night vision function. In last year's device, three cameras didn't have night vision, and one Wi-Fi camera with night vision. I tested all the cameras and they worked fine.
      But I ran into a problem here. WYZE's Wi-Fi camera only works on a 2.4GHz wireless network, and it only works on IOS or Android apps, which don't support the Windows system. So I took the camera back to my home and matched it, and it worked fine on 2G. The camera even has a voice feature that can accommodate Buzzer's intended role. I tried switching my iPad to 5G and other wi-fi environments, and everything worked fine. Finally, when I brought the camera to school for the final test, there was a problem. It turned out that the wireless camera was used as a transmitter to send data over a 2G network connected to the Internet, which was then received by the iPad as a receiver. Since the school is not allowed to use the Wi-Fi password, the camera cannot connect to the network. However, even if it can be used, the school's wireless network should be 5G and cannot match the camera. And the setting of having to send signals over the Internet broke the idea of setting up a local area network to solve the problem. Note that this does not mean that Wi-Fi cameras must need the Internet to work. When there is no Internet, SD cards can be used to record videos, but if you want to monitor in real-time, you need the Internet.
      So we still need to buy 4 wired cameras with night vision. Considering the price, if we use a USB camera, the price is slightly higher, but it saves us the cost of the adapter, so it's a better deal overall. And considering the size of the room, I believe the 720P camera is adequate. All things considered, I chose the camera shown below on Amazon. The cameras are lightweight, easy to install and remove, and can be taped to the ceiling.

      Besides, in the design of the safety exit sign, it is expensive to buy the “EXIT” sign lamp. If fluorescent cardboard or fluorescent tape is used, the effect is not good and the life of them is very short. Finally, we adopted Professor Dean's suggestion and realized it by using a transparent lighting filter. Since two “EXIT” signs are required, two sets of these transparent lighting filters are required if they are both green. The specific implementation method is shown in the following figure. Place a light source (round ball) in the box and cut a hole on one side with the word "EXIT". Paste filter paper on the inside of the box on this side, then light (arrows) can form the sign of the safety exit with the green light. The rest of the color filters may be used elsewhere in the future.