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 Robotics / RCX / 2194
  Re: Multiplexing 4 touch sensors on an RCX input port
 
(...) While in theory, this sounds very cool, in pratice, I doubt it will work quite that well. The biggest problem will be that the standard touch sensors may not be 100% on when you press it. This means the sensor itself can provide some (...) (21 years ago, 9-Sep-03, to lugnet.robotics.rcx)
 
  Re: Multiplexing 4 touch sensors on an RCX input port
 
(...) Good analysis. Series can work quite well as long as you know that the touch sensors are touched mutually exclusively, but you are right parallel doesn't work well. I remember trying to come up with good resistance values to do parallel, and (...) (21 years ago, 9-Sep-03, to lugnet.robotics.rcx)
 
  Re: Multiplexing 4 touch sensors on an RCX input port
 
I have done work in this area. I chose to solve the problem to permit 4 touch sensors to be pressed in any arbitrary combination with high probability of getting the answer right :) A simple R, 2R, 4R, 8R scheme will do. I chose R = 40.2K. This is (...) (21 years ago, 10-Sep-03, to lugnet.robotics.rcx)
 
  Re: Multiplexing 4 touch sensors on an RCX input port
 
(...) It works very well for me, with the variation that I use home-made touch sensors that are actually microswitches embedded into 2x2 blocks. That does mean you might need to debounce in software, but normally I don't bother since the inertia of (...) (21 years ago, 10-Sep-03, to lugnet.robotics.rcx)
 
  RE: Multiplexing 4 touch sensors on an RCX input port
 
(...) Ian, Great to see that you are having success with pbForth! I have a couple of questoins: 1. Which version are you using? 2. Are there any features you REALLY wish were available? 3. Do you have any stories or code to share? Ralph ---...--- (...) (21 years ago, 10-Sep-03, to lugnet.robotics.rcx, lugnet.robotics.rcx.pbforth)
 
  Re: Multiplexing 4 touch sensors on an RCX input port
 
"Steve Hassenplug" <Hassenplug@mail.com> wrote: [snip] (...) This has always annoyed me about the Lego touch sensors. Has anyone ever made or seen a contraption that uses the variable pressure sensitivity of the Lego touch sensors? Tim (21 years ago, 11-Sep-03, to lugnet.robotics.rcx)
 
  Re: Multiplexing 4 touch sensors on an RCX input port
 
(...) I've made one. A wall follower. I set the sensor to raw mode and looked at three ranges. It tried to stay in the middle range, which for this 'bot meant lightly touching the wall. The wall follower had a bumper analogous to a highly curved (...) (21 years ago, 12-Sep-03, to lugnet.robotics.rcx)
 
  Re: Multiplexing 4 touch sensors on an RCX input port
 
(...) (apologies for delay - my server decided to stop talking to lugnet for some reason, hopefully now fixed) (...) Errm, probably 2.1.0 (but I don't have it immediately to hand at the moment - that's the name of the directory on my computer with (...) (21 years ago, 18-Sep-03, to lugnet.robotics.rcx, lugnet.robotics.rcx.pbforth)

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