Pang, This is scary -- see my last post from a couple minutes ago, where I was relating the platform leveling to a car scale, which needs to be level. Funny you should say that your's is also for a car. IMHO, 15 deg resolution will not be useful. However, picture this... A non-electronic water level is a simple device that tells you what perfect level is no matter what the temp, etc. Get a clear hose, hold it in the shape of a "U" with both ends open and fill it with water. You'll notice that the top of water column are always at the same height, no matter what you do with the hose. You can move the ends apart many feet and it will still show you what is perfectly level. Another trick is to drop some oil on the top of each column to be able to read it easier. All you need now is some way to electronically measure the water level at both ends. You can use an array of optical sensors (I believe digikey has these in a single package of 16 or 32 sensors), and color the water. Or some ultrasonic sensor at the top of each end, both pointing downwards into the water. Perhaps you can put some type of light/hollow metal ball on top of the water on each end, and use a hall- effect sensor to detect it's level. Etc, etc, etc. Cheers, -Neil. -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Pang Sent: Wednesday, July 10, 2002 3:26 PM To: PICLIST@MITVMA.MIT.EDU Subject: Re: [EE]: Electronic Level Sensor Hi Mike and Neil, Frankly, I am not able to correctly visualise Mike suggestion. Are you trying to say we can install a few tilt switches with different angles. For example, Sensor A install in such a way that it will be tilted if the platform is raised by 15 deg. Sensor B install ........... 30 deg. Sensor C .......... 45 deg. So let say, a car (that's my intention :-)...) is tilted by 15 deg from normal, then sensor A will be tilted while sensor B & C will not be tilted.... OR if the tilted angle is 30 then A-off, B-on and C-off. What if in-between 15 and 30 deg? I don't know..... I guess the GP1S36 will be quite useful if it doesn't have the undefined state between 15 and 75 deg. Have never use an ultrasonic or water level sensor before, so wondering how high a resolution that can provide. Besides, if high resolution is needed (+-5mm) then the reading could be affected by the water temperature, maybe then we need another temp sensor....any other ideas?.... Best rgds, pang ----- Original Message ----- From: "Pic Dude" To: Sent: Thursday, July 11, 2002 1:58 AM Subject: Re: [EE]: Electronic Level Sensor > Another option... > > I really like water levels, as they are "self-calibrating". > Perhaps you can use something based on that. For example, > use a hose with a water-level sensor on both ends. This > could be something ultrasonic, something optical on the > outside with colored water, or electrodes in the water, etc. > And you'd need 2 such arrangements to level a platform with > 3 adjust points, or 3 arrangements if you have 4 adjustment > points. > > Cheers, > -Neil. > > > > > > -----Original Message----- > From: pic microcontroller discussion list > [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Mike Pink > Sent: Wednesday, July 10, 2002 10:36 AM > To: PICLIST@MITVMA.MIT.EDU > Subject: Re: [EE]: Electronic Level Sensor > > > Hi Pang > > Just joined the list so may have picked up late on this. > > Why not use 4 simple tilt switches (about #0.60/ $1 each ) and tilt each one > towards its respective corner so that when level all 4 are 'tilted'. Then as > the platform tips over the high side tilt switch will become level telling > you which direction to adjust. If you want to be really cheap you could use > plastic tubes with ball bearings and contact wires. > > Hope this helps > > Mike > > > ----- Original Message ----- > From: "Pang" > To: > Sent: Wednesday, July 10, 2002 4:33 AM > Subject: Re: [EE]: Electronic Level Sensor > > > > Hi Scott, > > > > I think the datasheet does not state the sense level of +-15 degrees. Both > > the transistor will be ON at +15 and -15 degrees. If the degree of tilting > > continue to be increase, one of the transistor will have be in undefine > > state. And that undefine state will continue until it reaches 75 degrees, > > where it will be in the OFF state. > > > > I didn't get what i been looking for ...(a cheap tilt sensor), but at > > least this is getting very near to the spec that i want. If only there is > a > > similar component with a slightly better angle characteristics. :-) > > > > Best rgds, > > pang > > > > > > ----- Original Message ----- > > From: "Scott M. Thomas" > > To: > > Sent: Wednesday, July 10, 2002 3:24 AM > > Subject: Re: [EE]: Electronic Level Sensor > > > > > > > These are not terribly accurate, but they are inexpensive. Can sense > > level > > > withing +-15 deg. > > > > > > http://rocky.digikey.com/WebLib/Sharp/Web%20Data/gp1s36.pdf > > > > > > -----Original Message----- > > > From: Terence Gunderson [mailto:tgunder@GTE.NET] > > > Sent: Monday, September 09, 2002 8:19 AM > > > To: PICLIST@MITVMA.MIT.EDU > > > Subject: [EE]: Electronic Level Sensor > > > > > > > > > Greetings and thanks in advance for any and all input: > > > > > > I need to have a platform automatically level itself. I am looking for > a > > > suitable sensor to electronically sense when the platform is at level. > > The > > > output of the sensor will be input to a micro the micro will then adjust > > > jack screws until it sees a level condition. > > > > > > Terry > > > > > > -- > > > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > > > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > > > > > -- > > > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > > > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > > > > > > > > > -- > > http://www.piclist.com hint: To leave the PICList > > mailto:piclist-unsubscribe-request@mitvma.mit.edu > > > > > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu > > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu