DrJB Posted October 10, 2013 Posted October 10, 2013 (edited) Moving from RCX to NXT, TLG integrated the rotation sensor into the motors and did away with the stand-alone angle sensor. I have a need for such functionality, but do not want to use a motor for (1. too bulky, 2. not free-rotating). What are options out there for stand-alone rotation sensor on EV3/NXT? Idealy, with pass-through axle hole of course. Edited October 11, 2013 by DrJB Quote
aol000xw Posted October 10, 2013 Posted October 10, 2013 Using an old sensor with the adapter or making your own with a touch sensor? Quote
DrJB Posted October 10, 2013 Author Posted October 10, 2013 (edited) On 10/10/2013 at 4:20 PM, aol000xw said: Using an old sensor with the adapter or making your own with a touch sensor? That's an idea, but I need continuous reading of the angle value (will be used as feedback signal for a closed-loop control system). Would the old RCX rotation sensor 9756-1 be compatible with EV3? Reason I'm asking is I just updated my EV3 installation to handle all sorts of sensors, and such rotation sensor is NOT amongst the list. Per Philo's page http://www.philohome.com/sensors/legorot.htm , I just found out such sensor 9756-1 is really not suitable for my application as it has rather poor angular resolution. I need resolution to within 5 degrees. One option would be to use gears with the sensor but then that brings in its own issues. I'm contemplating preloading the gears with this part x928cx1. Anyone tried to preload gears so as to remove backlash? Edited October 10, 2013 by DrJB Quote
JopieK Posted October 10, 2013 Posted October 10, 2013 http://www.hitechnic.com/cgi-bin/commerce.cgi?preadd=action&key=NAA1030 Should work well I think! If it doesn't need to be a continuous rotation one, you could also use this: http://www.brickengineer.com/pages/2009/10/05/interface-a-potentiometer-to-the-nxt/ Quote
DrJB Posted October 10, 2013 Author Posted October 10, 2013 (edited) On 10/10/2013 at 5:48 PM, JopieK said: http://www.hitechnic...ion&key=NAA1030 Should work well I think! If it doesn't need to be a continuous rotation one, you could also use this: http://www.brickengi...ter-to-the-nxt/ Thank you. The HiTechnic seems to be the solution ... but it is rather &^%$@# pricey! Edited October 11, 2013 by DrJB Quote
JopieK Posted October 10, 2013 Posted October 10, 2013 That is why I included the other option which is rather do-it-yourself-but-very-cheap ;) Quote
DrJB Posted October 10, 2013 Author Posted October 10, 2013 (edited) Thank you. That sounds like the more 'reasonable' path. Edited October 11, 2013 by DrJB Quote
Jim Posted October 10, 2013 Posted October 10, 2013 HiTechnic sensors are great! They work properly and they match the Lego form factor. However, they are rather pricey. On 10/10/2013 at 5:24 PM, DrJB said: Anyone tried to preload gears so as to remove backlash? I have used the caster ball from the EV3 educational set as a weight to "preload" the gears. However, this will only work if you can use gravity as a force vector. Quote
TasV Posted October 11, 2013 Posted October 11, 2013 The title says EV3 but your opening sentence says NXT. Are looking for NXT or EV3? Either way... this mindsensors sensor should do what you are after: http://www.mindsensors.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=173 Quote
Jim Posted October 11, 2013 Posted October 11, 2013 Totally forgot about the Mindsensors rotation sensor. Nice suggestion! Quote
CopyCatz Posted October 11, 2013 Posted October 11, 2013 Make sure you either buy a new one from Mindsensors with EV3 firmware or have a NXT brick around to flash an older one to EV3... I bought one that had no EV3 fw, but I have no NXT brick to flash it... Quote
DrJB Posted October 11, 2013 Author Posted October 11, 2013 Thank you, that is more affordable than other options. I'll be using it with EV3. The photo on mindsensors's web page shows the sensor only, but not the connector end of the cable. Is it safe to assume that the cable has the right connector and thus, the sensor is ready to use out of the box? Quote
Jim Posted October 11, 2013 Posted October 11, 2013 Yes, it's ready. From the manual: Connections and Placement Connect GlideWheel-AS connector to Sensor Port of your NXT. Quote
TasV Posted October 11, 2013 Posted October 11, 2013 (edited) The website (link above) states it is compatible with NXT, EV3, and Arduino and can be programmed in NXT-G, RobotC, NXC, and EV3 (whatever it is called). On the link provided above you can download NXT-G blocks, EV3 blocks and see sample EV3 programs. The ribbon cable going into it has the plug on it to go into your sensor ports straight out of the box. This link: http://www.mindsensors.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=192&MMN_position=32:32 ...explains which Mindsensors need firmware upgrades and how to upgrade them. The Glidewheel-AS requires a firmware upgrade. Edited October 11, 2013 by TasV Quote
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