brentonw2004
New Member
Hello all. About a year ago I made a robotic lawn mower. Basically it is a normal lawn mower that uses a gasoline engine to spin the blade and spin an altenator to charge two 12V batteries. The batteries are then used to power a couple wheelchair motors, one attached to each wheel. I have a wireless camera attached to this and I drive it using a remote control. I know, I could be one of the laziest people alive. I would like to take this laziness one step further and completely automate the system. To do this I need to have a way for the robot to know its position in the yard. I do not want to use any type of buried wire type system. I have thought about two different ways of possibly doing this, but I would definitely appreciate ideas on which is better or even which would work. First idea is to use a GPS system. I do not know however much about the accuracy of these system. I have heard that most are only accurate down to 3-5m, this would be very unacceptable for my needs. However, I do not completely understand if that means that they could be inaccurate on the actual position, but how about accuracy on a local scale. For example, if I take a reading at one postion and move .5m away, will it recognize this change in distance accurately? It is not a problem if the system is not exactly accurate on finding the global position of the robot, it is however important that it accurately find the position of the robot on a local scale(one position relative to another local position.) I hope I explained myself good enough. My second idea is to use something like a radio beacon. I thought this could be achieved by syncronizing a clock on the robot with a clock on the beacon, then sending out a radio signal from the beacon to the robot with somewhat of a timestamp on it, then using this timelapse to calculate the distance from the beacon to the robot. I imagine that I would have to use at least three beacons to correctly calculate the correct position with no ambiguity. I need an accuracy of at least .1m. Would this either of these ideas be even remotely possible? I know that the beacon idea should work in theory, but would a typical microchip(pic/motorola) be able to work fast enough to measure such small time lapses? Any advice would be greatly appreciated.