First off I am a complete noob. I have an Arduino and made an LED blink and fade so keep that in mind.
I have a little bit of programming experience. higher level languages.
I have very little electronics experience. Can read a resistor.
I want to make a remote controlled Lawnmower / ice fishing shanty mover. I know! "What?" -- In the summer I want to push/pull my mower around and in the winter I want to push pull my ice fishing Clam Shell hut around on the ice.
Lawnmower -- I have a push mower to tear apart and use.Motor -- I have an old three wheel scooter(older than the ones you find at stores etc.) It has a working 24 VDC motor (don't know the amps) It also has a 12VDC type of magnetic brake - I think. If I apply 12vdc to the one wire it releases the brake. If I apply 12vdc (I don't have two batteries yet for 24VDC) to the motor it moves the one wheel. The electronics on the scooter (controller) are fried or at least don't work.
The cool thing about the scooter is that the platform (seat, foot rest, front wheel, steering pole, etc.) is removable which leaves just the motor attached to a 1" square metal frame with a short 4" piece sticking out the front that goes into the front part and is secured with a pin. I think it was designed to be taken apart into two pieces to put in the trunk of a car for transport. It seems powerful enough for what I want to do.
The Idea:1. So here is the idea that came to mind. I don't want to destroy this thing but rather hook up the Uno to it to control it (eventually from my iPad/iPhone) you know; forward, reverse, stop, speed. Then after I get motor control I want to drive it around sitting on it. Next, I want to build a 1" metal receiver to hook it to a push lawnmower. and drive that around. Lastly, I want to unhook it and hook it to my ice fishing shanty which will also have a 1" receiver as well.
A regular all around helper bot with controls I know how to use. This seems the easy part.
The Hard Parts:2. For the Mower and unmanned riding I want to come up with a way to steer this thing. So I am researching gears and motors etc. I do have a cordless screwdriver to tear apart first and see if it has enough torque to turn a gear (forward/reverse) and if it is sensitive enough to gain good direction control. I think the screwdriver has variable speed so I think it is slow enough.
3. Once I have steering I want to look into unmanned or at least remote control. Being familiar with a Roomba i.e. (The "it doesn't know where it is, it only cares if it bumps into something and the sensor tells it to back up and turn slightly and try again" part.) I know it does more than that to cover areas decently but for now I just want to emulate that part.
3a. For unmanned control I was thinking of four posts to quadrant off an area with some type of beam (light, laser, sound, etc.) then when the mower hits the beam it stops and reverse x amount of time/distance then turns and tries again until it has free movement. I will start out with squares for now so that this is simpler. In effect using the beams as the bumpers/sensors.
3b. For remote control I was thinking of video fed to my iPhone/iPad and then I can steer it myself from in the house. I actually suffer from heat intolerance severely and can die if exposed too long to the sun in hot weather so this would be great to cut the grass from an air conditioned environment. So far I know that the remote control can be done with some combination of OSC and maybe xBee or something for controlling and I thought I saw a video board but haven't researched that yet.
So, I really would appreciate any suggestions on number 2 and 3a. I'm going to document each step of this project. Even though I think this is a lot to shew on being a total noob I am not duanted by the task and plan on doing the best I can to reach all of these goals.Any help and suggestions are greatly appreciated.
(because with relays you can't really control the speed of the motor);
OH PLEASE!!!Of course you should have a safety system in place especially with something with a spinning blade but you, me and the OP know that such a device would cause more harm then good (false readings, complicated implementation).
Quote:(because with relays you can't really control the speed of the motor);This is false.I have PWM'd relays to control motor speed.It works ok but its noisy and the speed control is alittle rough.
FWIW Sending video over wireless with arduino sounds challenging.
I am not saying safety is not VERY important.
I am just saying a heartbeat monitor is guaranteed not the way to implement it.It is not the normal way to monitor safety and is plain inaccurate.Set too low and the excitement of trying it shuts it off immediately, set too high and its useless.
FWIW, You should have a LARGE relay on the main power to the motors and in case the safety system is triggered, it will kill all motor power even in the event of the relay or mosfet controlling the motors short.