Ned Posted July 21, 2013 Share Posted July 21, 2013 What sort of power supply are you using? Those motors can pull a fair bit if current... If its overloading your power supply, it could get mad voltage sag and beep due to under voltage. I'll put mine on the logic analyzer and see how they are really driven and see how difficult it would be Quote Link to comment Share on other sites More sharing options...
mikey Posted July 21, 2013 Author Share Posted July 21, 2013 Yeah, if we can get an ESC to run slow enough and at fixed speeds then I'll go that way. But at the moment it's looking easier to rip the guts out of the speedo and hook a stepper up to the needle. I can hook another stepper up to the odometer. Just seems easier to me now? I'm reaching the limit of my know-how with driving the BLDC from the PIC I think, even with the L239D motor driver. Quote Link to comment Share on other sites More sharing options...
Ned Posted July 21, 2013 Share Posted July 21, 2013 I will have a quick play, hopefully tonight and see what i can do. Might spend some work time looking for some ESC code to play with etc Quote Link to comment Share on other sites More sharing options...
Simon Posted July 21, 2013 Share Posted July 21, 2013 Yeah, if we can get an ESC to run slow enough and at fixed speeds then I'll go that way. But at the moment it's looking easier to rip the guts out of the speedo and hook a stepper up to the needle. I can hook another stepper up to the odometer. Just seems easier to me now? I'm reaching the limit of my know-how with driving the BLDC from the PIC I think, even with the L239D motor driver. Nah don't do that. I havent the time to look through all this but heres a BLDC motor driver chip. I don't think the one you're using is designed for BLDC? http://www.ti.com/product/drv8313 Quote Link to comment Share on other sites More sharing options...
Simon Posted July 21, 2013 Share Posted July 21, 2013 Actually, that looks like you can't just fire a PWM at it.. Ned, whip us up some synchronous code to drive this lol Quote Link to comment Share on other sites More sharing options...
Ned Posted July 21, 2013 Share Posted July 21, 2013 I have an ESC here thats the same as the one i dropped off to Mikey yesterday and me and the multimeter are tracing everything so i can draw up a schematic. Once i've done that, i'll be able to write/modify some code to see it i can get it to do something sensible Stay tuned Quote Link to comment Share on other sites More sharing options...
mikey Posted July 21, 2013 Author Share Posted July 21, 2013 YEAHYA! Awesome. Quote Link to comment Share on other sites More sharing options...
Ned Posted July 22, 2013 Share Posted July 22, 2013 Havent done a lot of real work at work today.... have made this though Not sure if its 100% correct, but it should be good enough to be able to have a play and see if i can make a motor do something sensible. Another thing Mikey, if you get a motor with more poles, it will slow it down also. So will see what i can do, but when it comes down to motor buying, you probably want the lowest KV and highest pole count to get the best resolution and lowest speed etc. Quote Link to comment Share on other sites More sharing options...
mikey Posted July 22, 2013 Author Share Posted July 22, 2013 Awesome work! Quote Link to comment Share on other sites More sharing options...
mikey Posted July 29, 2013 Author Share Posted July 29, 2013 I think I'm gonna change tack. This BLDC thing seems quite tricky. So what is probably easier is driving the needle and the odo with little stepper motors I just pinched from old CDROM's at work: I even have a proof of concept we made whilst pissing around: Quote Link to comment Share on other sites More sharing options...
Ned Posted July 29, 2013 Share Posted July 29, 2013 That looks cool as well. Would be handy for diesels haha Tonight was going to be trying to get the motor controller to do something sensible, but that idea would be a lot quieter etc as well. I mean getting an RC motor to spin at x RPM constantly has to make some noise of some description, but the stepper will probably be pretty quiet Quote Link to comment Share on other sites More sharing options...
ProZac Posted August 1, 2013 Share Posted August 1, 2013 I did basically the same thing you're doing once upon a time with a mini speedo. I replaced the original odometer with a display though, so that part was much easier. I drove the needed with a VID29 stepper motor, straight from an arduino. Ive got a bunch of left over VID29 stepper motors though: http://guy.carpenter.id.au/gaugette/resources/vid/20091026113525_VID29_manual_EN-080606.pdf they're specifically for gauges, are internally geared to have a small degree of shaft movement per step. Run them with a proper controller, microstepping them, and you can make them completely seamless. Your's if you want a couple to play with? Quote Link to comment Share on other sites More sharing options...
ProZac Posted August 1, 2013 Share Posted August 1, 2013 Wouldn't be suitable for driving the odometer though, as they're pretty weak, and have internal stops at the end of their travel. I think we should have our own electronics section of the forum, BTW . 1 Quote Link to comment Share on other sites More sharing options...
Ned Posted August 1, 2013 Share Posted August 1, 2013 Those look sweet! I have 2 of these if you wanna play with them/have them http://dx.com/p/5v-stepper-motor-uln2003-driver-board-set-158635 i tried playing with the ESC but broke one of the programming pins and decided to put it in the too hard basket for now, especially since i actually need those ESCs for my plane and dont want to destroy the code thats on them Quote Link to comment Share on other sites More sharing options...
mikey Posted August 2, 2013 Author Share Posted August 2, 2013 I did basically the same thing you're doing once upon a time with a mini speedo. I replaced the original odometer with a display though, so that part was much easier. I drove the needed with a VID29 stepper motor, straight from an arduino. Ive got a bunch of left over VID29 stepper motors though: http://guy.carpenter.id.au/gaugette/resources/vid/20091026113525_VID29_manual_EN-080606.pdf they're specifically for gauges, are internally geared to have a small degree of shaft movement per step. Run them with a proper controller, microstepping them, and you can make them completely seamless. Your's if you want a couple to play with? Oh mean! I actually just found these little suckers on ebay a couple of days ago. I've ordered one, hopefully it doesn't take too long to show up, they look perfect. Glad to hear I'm not the only one who's done something like this. I pulled apart the speedo tonight and removed all the mechanical cable input. I mounted a stepper motor on the odometer and it spins the odometer and trip meter perfectly. So all I have to do is wait for the speedo stepper and mount that. Those look sweet! I have 2 of these if you wanna play with them/have themhttp://dx.com/p/5v-stepper-motor-uln2003-driver-board-set-158635 i tried playing with the ESC but broke one of the programming pins and decided to put it in the too hard basket for now, especially since i actually need those ESCs for my plane and dont want to destroy the code thats on them Which reminds me, I have to drop off your other motor and ESC I have here. Thanks for letting me play with them, even though I wont be using them it was all part of the process of getting to this point. When suits? Whats your addr? Quote Link to comment Share on other sites More sharing options...
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