From steve at chalem.com Sat Apr 5 23:12:41 2008 From: steve at chalem.com (Steve Chalem) Date: Sat Apr 5 23:13:27 2008 Subject: [dorkbotsebastopol-blabber] Braking DC motors, anyone? Message-ID: <3606B5BAD467A349AC94B0D05164DBD603EA4E90@EXVBE014-13.exch014.msoutlookonline.net> Reading up on h-bridges, I see that when turned on they have four possible output states: clockwise, counterclockwise, brake to Vcc, and brake to Gnd. Question: does it matter whether one brakes to Vcc or to Gnd? Under what circumstances would one want to do one or the other? From steve at chalem.com Mon Apr 7 20:21:41 2008 From: steve at chalem.com (Steve Chalem) Date: Mon Apr 7 20:21:58 2008 Subject: FW: [dorkbotsebastopol-blabber] Stepper annoyances Message-ID: <3606B5BAD467A349AC94B0D05164DBD603F2342D@EXVBE014-13.exch014.msoutlookonline.net> Brad, I repeated the experiment with the changes we discussed, and got the same result. I separated the power supply from the electronics and also connnected the negative side to ground. I put a bigger heat sink on the chip, and I also tested the setup with the easydriver initially cold. Again, the big motor went back and forth hesitantly and jerkily; and the small motor just fluttered. Adjusting the pot did change the behavior, but there was no setting where either motor worked correctly. If you're stillinterested in trying our setups side-by-side, let me know! --Steve ________________________________ From: dorkbotsebastopol-blabber-bounces@music.columbia.edu [mailto:dorkbotsebastopol-blabber-bounces@music.columbia.edu] On Behalf Of Steve Chalem Sent: Monday, March 24, 2008 10:17 AM To: bsilva@sonic.net Cc: dorkbotsebastopol-blabber@dorkbot.org Subject: [dorkbotsebastopol-blabber] Stepper annoyances Brad, I'll try both motors with a just-powered-up ezdriver and let you know what happens. I'm in Oakland for a few days, so I won't be able to try it until Thursday or so. (I'm also not expecting to make the Wed. nite meeting this week.) Re next steps, I'd like to compare your setup with mine and it'd be great to have your help diagnosing this. Friday or next weekend should be good, or one day the following week. Meanwhile I'll try the above and also a bigger heat sink and twiddling the pot. --Steve ________________________________ From: bsilva [mailto:bsilva@sonic.net] Sent: Sun 3/23/2008 9:29 PM To: Steve Chalem Cc: dorkbotsebastopol-blabber@dorkbot.org Subject: Re: Stepper annoyances Well, I have a small epson (looks like two pancake coils sandwiched together (Hmmm.. Two food metaphors in one sentence, must be hungry)) and it's working fine. One difference, it's a six wire unit and yours is a four. I think the next step is to bring my test setup to your shop along with my scope and see what's different. I'm not sure I can do this week though, I have some major paperwork to do along side my normal job. I'll try though, I'm very curious about this. Brad P.S. Does the stepper exhibt the same symptoms immediately after powering on the ezstepper? i.e. Could we looking at the ezstepper going into thermal shutdown? Two suggestions; try a bigger heatsink and try turning the current limit pot clockwise. I've taken a real close look at the pot on my unit and viewed from the side you can see where a top and bottom piece of metal come together. It appears that the wiper is directly opposite this fold. It also appears that if the wiper is pointed at the "adj" marking the current should be at its minimum. That's assuming that your wiper is the same type as mine. Hmm... too many vague statements in this paragraph. I think I'm going to write the guys at Sparkfun and ask them to put a pot on this thing where it's possible to have a clue as to how it's set. On Sun, 23 Mar 2008, Steve Chalem wrote: > Brad, > > I did some more tests, this time with an ezdriver connected *directly* to the arduino (no ribbon cable); the "wall-wart" 12v power supply; short, direct wiring between the ezdriver and the motor, and a solid ground connection between the motor/driver circuit and the arduino. > > Result: same as before! The .4A vexta (or whatever) motor turns back and forth once the amp-limit trim pot is fine-tuned, but on closer examination is skipping a lot of steps. The little epson motor just flutters. > > Our hypothesis that the problems are caused by 60hz noise reaching the "direction" pin still makes sense, although of course i can't confirm the presense of the noise without an oscilliscope. BUT, I've done everything we discussed to eliminate noise and saw no change in behavior. > > One addl data point: the only time I've actually witnessed an ezdriver operating a motor properly was when you had one connected to a bitwhacker. I've never actually seen one work with an arduino. I do know people are using this combination successfully. > > --Steve > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://music.columbia.edu/pipermail/dorkbotsebastopol-blabber/attachments/20080407/f0bc9a9a/attachment.html From bsilva at sonic.net Mon Apr 7 22:54:25 2008 From: bsilva at sonic.net (bsilva) Date: Mon Apr 7 22:55:08 2008 Subject: FW: [dorkbotsebastopol-blabber] Stepper annoyances In-Reply-To: <3606B5BAD467A349AC94B0D05164DBD603F2342D@EXVBE014-13.exch014.msoutlookonline.net> References: <3606B5BAD467A349AC94B0D05164DBD603F2342D@EXVBE014-13.exch014.msoutlookonline.net> Message-ID: Very interested. In absense of any other announced DB event this wednesday, shall we get together then? Otherwise I have Thursday open. Brad On Mon, 7 Apr 2008, Steve Chalem wrote: > Brad, I repeated the experiment with the changes we discussed, and got > the same result. > > I separated the power supply from the electronics and also connnected > the negative side to ground. I put a bigger heat sink on the chip, and > I also tested the setup with the easydriver initially cold. > > Again, the big motor went back and forth hesitantly and jerkily; and the > small motor just fluttered. Adjusting the pot did change the behavior, > but there was no setting where either motor worked correctly. > > If you're stillinterested in trying our setups side-by-side, let me > know! > > --Steve > > > ________________________________ > > From: dorkbotsebastopol-blabber-bounces@music.columbia.edu > [mailto:dorkbotsebastopol-blabber-bounces@music.columbia.edu] On Behalf > Of Steve Chalem > Sent: Monday, March 24, 2008 10:17 AM > To: bsilva@sonic.net > Cc: dorkbotsebastopol-blabber@dorkbot.org > Subject: [dorkbotsebastopol-blabber] Stepper annoyances > > > Brad, I'll try both motors with a just-powered-up ezdriver and let you > know what happens. > > I'm in Oakland for a few days, so I won't be able to try it until > Thursday or so. (I'm also not expecting to make the Wed. nite meeting > this week.) > > Re next steps, I'd like to compare your setup with mine and it'd be > great to have your help diagnosing this. Friday or next weekend should > be good, or one day the following week. > > Meanwhile I'll try the above and also a bigger heat sink and twiddling > the pot. > > --Steve > > > > ________________________________ > > From: bsilva [mailto:bsilva@sonic.net] > Sent: Sun 3/23/2008 9:29 PM > To: Steve Chalem > Cc: dorkbotsebastopol-blabber@dorkbot.org > Subject: Re: Stepper annoyances > > > > > Well, I have a small epson (looks like two pancake coils sandwiched > together (Hmmm.. Two food metaphors in one sentence, must be hungry)) > and > it's working fine. One difference, it's a six wire unit and yours is a > four. > > I think the next step is to bring my test setup to your shop along with > my > scope and see what's different. > > I'm not sure I can do this week though, I have some major paperwork to > do > along side my normal job. I'll try though, I'm very curious about this. > > > Brad > > P.S. Does the stepper exhibt the same symptoms immediately after > powering > on the ezstepper? i.e. Could we looking at the ezstepper going into > thermal shutdown? > > Two suggestions; try a bigger heatsink and try turning the current limit > pot clockwise. I've taken a real close look at the pot on my unit and > viewed from the side you can see where a top and bottom piece of metal > come together. It appears that the wiper is directly opposite this > fold. > It also appears that if the wiper is pointed at the "adj" marking the > current should be at its minimum. That's assuming that your wiper is > the > same type as mine. Hmm... too many vague statements in this paragraph. > I think I'm going to write the guys at Sparkfun and ask them to put a > pot > on this thing where it's possible to have a clue as to how it's set. > > > > On Sun, 23 Mar 2008, Steve Chalem wrote: > > > Brad, > > > > I did some more tests, this time with an ezdriver connected *directly* > to the arduino (no ribbon cable); the "wall-wart" 12v power supply; > short, direct wiring between the ezdriver and the motor, and a solid > ground connection between the motor/driver circuit and the arduino. > > > > Result: same as before! The .4A vexta (or whatever) motor turns back > and forth once the amp-limit trim pot is fine-tuned, but on closer > examination is skipping a lot of steps. The little epson motor just > flutters. > > > > Our hypothesis that the problems are caused by 60hz noise reaching the > "direction" pin still makes sense, although of course i can't confirm > the presense of the noise without an oscilliscope. BUT, I've done > everything we discussed to eliminate noise and saw no change in > behavior. > > > > One addl data point: the only time I've actually witnessed an > ezdriver operating a motor properly was when you had one connected to a > bitwhacker. I've never actually seen one work with an arduino. I do > know people are using this combination successfully. > > > > --Steve > > > > > From steve at chalem.com Mon Apr 7 23:11:08 2008 From: steve at chalem.com (Steve Chalem) Date: Mon Apr 7 23:11:25 2008 Subject: FW: [dorkbotsebastopol-blabber] Stepper annoyances In-Reply-To: References: <3606B5BAD467A349AC94B0D05164DBD603F2342D@EXVBE014-13.exch014.msoutlookonline.net> Message-ID: <3606B5BAD467A349AC94B0D05164DBD603F234AC@EXVBE014-13.exch014.msoutlookonline.net> Sounds good to me. Unless someone has something else planned for Wednesday evening's meeting, let's work on it then. -----Original Message----- From: bsilva [mailto:bsilva@sonic.net] Sent: Monday, April 07, 2008 7:54 PM To: Steve Chalem Cc: dorkbotsebastopol-blabber@dorkbot.org Subject: Re: FW: [dorkbotsebastopol-blabber] Stepper annoyances Very interested. In absense of any other announced DB event this wednesday, shall we get together then? Otherwise I have Thursday open. Brad On Mon, 7 Apr 2008, Steve Chalem wrote: > Brad, I repeated the experiment with the changes we discussed, and got > the same result. > > I separated the power supply from the electronics and also connnected > the negative side to ground. I put a bigger heat sink on the chip, > and I also tested the setup with the easydriver initially cold. > > Again, the big motor went back and forth hesitantly and jerkily; and > the small motor just fluttered. Adjusting the pot did change the > behavior, but there was no setting where either motor worked correctly. > > If you're stillinterested in trying our setups side-by-side, let me > know! > > --Steve > > > ________________________________ > > From: dorkbotsebastopol-blabber-bounces@music.columbia.edu > [mailto:dorkbotsebastopol-blabber-bounces@music.columbia.edu] On > Behalf Of Steve Chalem > Sent: Monday, March 24, 2008 10:17 AM > To: bsilva@sonic.net > Cc: dorkbotsebastopol-blabber@dorkbot.org > Subject: [dorkbotsebastopol-blabber] Stepper annoyances > > > Brad, I'll try both motors with a just-powered-up ezdriver and let you > know what happens. > > I'm in Oakland for a few days, so I won't be able to try it until > Thursday or so. (I'm also not expecting to make the Wed. nite meeting > this week.) > > Re next steps, I'd like to compare your setup with mine and it'd be > great to have your help diagnosing this. Friday or next weekend > should be good, or one day the following week. > > Meanwhile I'll try the above and also a bigger heat sink and twiddling > the pot. > > --Steve > > > > ________________________________ > > From: bsilva [mailto:bsilva@sonic.net] > Sent: Sun 3/23/2008 9:29 PM > To: Steve Chalem > Cc: dorkbotsebastopol-blabber@dorkbot.org > Subject: Re: Stepper annoyances > > > > > Well, I have a small epson (looks like two pancake coils sandwiched > together (Hmmm.. Two food metaphors in one sentence, must be hungry)) > and it's working fine. One difference, it's a six wire unit and yours > is a four. > > I think the next step is to bring my test setup to your shop along > with my scope and see what's different. > > I'm not sure I can do this week though, I have some major paperwork to > do along side my normal job. I'll try though, I'm very curious about > this. > > > Brad > > P.S. Does the stepper exhibt the same symptoms immediately after > powering on the ezstepper? i.e. Could we looking at the ezstepper > going into thermal shutdown? > > Two suggestions; try a bigger heatsink and try turning the current > limit pot clockwise. I've taken a real close look at the pot on my > unit and viewed from the side you can see where a top and bottom piece > of metal come together. It appears that the wiper is directly > opposite this fold. > It also appears that if the wiper is pointed at the "adj" marking the > current should be at its minimum. That's assuming that your wiper is > the same type as mine. Hmm... too many vague statements in this > paragraph. > I think I'm going to write the guys at Sparkfun and ask them to put a > pot on this thing where it's possible to have a clue as to how it's > set. > > > > On Sun, 23 Mar 2008, Steve Chalem wrote: > > > Brad, > > > > I did some more tests, this time with an ezdriver connected > > *directly* > to the arduino (no ribbon cable); the "wall-wart" 12v power supply; > short, direct wiring between the ezdriver and the motor, and a solid > ground connection between the motor/driver circuit and the arduino. > > > > Result: same as before! The .4A vexta (or whatever) motor turns > > back > and forth once the amp-limit trim pot is fine-tuned, but on closer > examination is skipping a lot of steps. The little epson motor just > flutters. > > > > Our hypothesis that the problems are caused by 60hz noise reaching > > the > "direction" pin still makes sense, although of course i can't confirm > the presense of the noise without an oscilliscope. BUT, I've done > everything we discussed to eliminate noise and saw no change in > behavior. > > > > One addl data point: the only time I've actually witnessed an > ezdriver operating a motor properly was when you had one connected to > a bitwhacker. I've never actually seen one work with an arduino. I > do know people are using this combination successfully. > > > > --Steve > > > > > From steve at chalem.com Wed Apr 9 11:19:44 2008 From: steve at chalem.com (Steve Chalem) Date: Wed Apr 9 11:20:09 2008 Subject: [dorkbotsebastopol-blabber] Tonight's Meeting Message-ID: <3606B5BAD467A349AC94B0D05164DBD603F23C3C@EXVBE014-13.exch014.msoutlookonline.net> Brad: We can meet at my shop tonight, unless you have another preference. What's a convenient time? Should we plan to order food? --Steve From bsilva at sonic.net Wed Apr 9 14:08:50 2008 From: bsilva at sonic.net (bsilva) Date: Wed Apr 9 14:09:36 2008 Subject: [dorkbotsebastopol-blabber] Re: Tonight's Meeting In-Reply-To: <3606B5BAD467A349AC94B0D05164DBD603F23C3C@EXVBE014-13.exch014.msoutlookonline.net> References: <3606B5BAD467A349AC94B0D05164DBD603F23C3C@EXVBE014-13.exch014.msoutlookonline.net> Message-ID: I was planning on being there about 6 and bringing something to eat. I'd like to get done a little earlier than usual (;-), as I have a busy day starting early tomorrow. Brad On Wed, 9 Apr 2008, Steve Chalem wrote: > Brad: > > We can meet at my shop tonight, unless you have another preference. > What's a convenient time? Should we plan to order food? > > --Steve > > From rich.gibson at gmail.com Wed Apr 9 14:18:33 2008 From: rich.gibson at gmail.com (Rich Gibson) Date: Wed Apr 9 14:18:47 2008 Subject: [dorkbotsebastopol-blabber] Re: Tonight's Meeting In-Reply-To: References: <3606B5BAD467A349AC94B0D05164DBD603F23C3C@EXVBE014-13.exch014.msoutlookonline.net> Message-ID: Awesome! I am planning to come by. I'm in the mood for a Torta (what a shock, eh?) Cheers, Rich On Wed, Apr 9, 2008 at 11:08 AM, bsilva wrote: > > I was planning on being there about 6 and bringing something to eat. > > I'd like to get done a little earlier than usual (;-), as I have a busy > day starting early tomorrow. > > > Brad > > > > > On Wed, 9 Apr 2008, Steve Chalem wrote: > > > Brad: > > > > We can meet at my shop tonight, unless you have another preference. > > What's a convenient time? Should we plan to order food? > > > > --Steve > > > > > ........................................................................ > .........dorkbot: people doing strange things with electricity.......... > ..........................http://dorkbot.org............................ > ........................................................................ > -- Rich Gibson Chief Scientist (and bottle washer), Locative Technologies http://mappinghacks.com http://geocoder.us http://testingrange.com AIM period3equals From steve at chalem.com Tue Apr 22 17:16:11 2008 From: steve at chalem.com (Steve Chalem) Date: Tue Apr 22 17:16:30 2008 Subject: [dorkbotsebastopol-blabber] Wednesday Hack Night at Steve's Studio Message-ID: <3606B5BAD467A349AC94B0D05164DBD6040DDF7D@EXVBE014-13.exch014.msoutlookonline.net> We'll be having another hack night at my place tomorrow night. Doors open at 6pm. Please write if you need directions. Brad might bring a hobby-servo-powered puppet stage; he's planning to put a bitwacker at the helm. Bruce and Steve are going to take some measurements for the storage loft so we can get some of the STUFF off the floor. Steve just got some new EasyDriver stepper-motor drivers, so Bruce and Steve are hoping to get the flea circus all wired up and ready to go. Additional projects, helping hands, curious observers and conversationalists are all welcome. Food and beverage will be collectively purchased and consumed. From steve at chalem.com Tue Apr 29 02:09:01 2008 From: steve at chalem.com (Steve Chalem) Date: Tue Apr 29 02:36:20 2008 Subject: [dorkbotsebastopol-blabber] This Wednesday Night Message-ID: <3606B5BAD467A349AC94B0D05164DBD60414CAF8@EXVBE014-13.exch014.msoutlookonline.net> Ideas, anyone? More hacking and tortas at my place? Can we whip anything together for the Faire?