by David Tow and Emily Cheng
After more than four weeks of designing, debugging, and tweaking, we have a fully functional wireless drawing device. We are able to use a wireless keypad to draw on a television screen. This project would have been much more intensive harder had we needed to code all the television timing and blasting to the television code ourselves. We are under our budget limit for the project. We spent a total of $5.77 on the transmitter and receiver only. We got the regulator and op-amp from the lab
If we were to do this project again, we would have initially started with the keypad instead of trying to get the photosensors working. After getting the keypad wireless drawing to work, we would then implement the photosensors, so that the user can use our drawing device like a mouse to draw on the television.
Our project is a wireless design. We are not infringing on anyone's patents by building it, but had wireless mice not been around for so long, we may very well have broken some patent laws. Our wireless medium is RF with transmissions at about 433 MHz. Nothing in this project is too hazardess to one's health. Although, on occasion, the voltage regulator would get rather hot. When that occurred, we would merely disconnect the battery source to let it cool down. So, if this were a real marketable product, we would have to take care of that issue, as well as probably making it prettier to the eye.
When we were working with our RF, there was usually at least one other group using the same frequency as we. Therefore, we needed to share the bandwidth. Obviously, sending all sorts of RF signals around the small lab room will cause interference in each other's transmissions, so we would always need to talk to the other to make sure that when we were running our transmissions, they would not and vice versa. Everyone that we talked with in the labs always seem agreeable to these circumstances.
Our original primary goal was to get the photosensors working and have the wireless drawing occur via the use of a mouse-like device; however, it took us far too much time to try to figure out how an optical photosensor worked. We searched every hardware site that we could find and asked the TA's and the Professor if they knew of a schematic on the device, but we could not find one. Since we had no schematic on this optical photosensor (it was a part laying around in the lab), by the time we got the photosensor running properly, we still needed to get the optical encoder and directional movements working. We truly wanted to make a wireless mouse - one that looked like a mouse, and not a keypad, for this drawing device. we believed that we could feasibly do so. However, the time constraints just got us. We had no working drawing device with about a week left, so we ported over to getting a wireless drawing keypad to work first, and then get back to trying to get the optical photosensors working if there was still time remaining. So, we ended up having only a wireless keypad drawing device.
Throughout the lab sessions and extra hour sessions, the TA's, especially Sean and Chris, and the Professor were exceptionally helpful. There were times when some minute thing would just not work or times when we were trying to figure out a best design for our circuits, and we would be stuck trying to debug a tiny bug in our circuit or our program. It did not matter which of those three that we would ask, but each would always be quite able to help us.