Timeline for Debugging my Stepper Motor Driver circuit
Current License: CC BY-SA 3.0
13 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 4, 2014 at 18:20 | comment | added | Anonymous Penguin | @Chris I stand corrected, I must be buying cheap batteries :) Anyway, you only need the first three letters for a ping. | |
| May 4, 2014 at 17:12 | comment | added | Chris Stratton | @AnnonomusPenguin - a single AA cell can in fact provide several amps. One of the real problems with specialist sites such as this is that topics get diverted to a backwater where there's a shortage of actual knowledge and a lot of mistaken information. Also, if you are going to make site usage recommendations, you could start by using someone's actual username in your @ notification - otherwise, you depend on the automatic notification to those in the preceding posts. | |
| May 4, 2014 at 14:14 | comment | added | Anonymous Penguin | @Paul Like others have pointed out, the best route as far as I know to debug this further is to get a power supply that can for sure supply the right amount of electricity. You could also use an old PSU for this purpose... | |
| May 4, 2014 at 14:10 | comment | added | Anonymous Penguin |
@Chris Please ping the person you are talking to with @Username so they will get pinged. Anyway, can one AA supply 2A? You have to remember in series that the voltage characteristics are added, but the current characteristics are those of only one battery. I'm concerned that one AA won't be able to provide 1.5V 1.8A, which is what the OP needs.
|
|
| May 4, 2014 at 13:58 | comment | added | Chris Stratton | Do not use lithium - there are real concerns though not quite as erroneously described here. Alkaline AA's can easily supply 2 amps, though only for a bit less than an hour. You really should use a power supply. | |
| May 4, 2014 at 13:17 | comment | added | Paul | @AnnonomusPenguin: I am using alkaline batteries. Perhaps switching to lithium would work better? I've heard that they can provide more amps... | |
| May 4, 2014 at 12:59 | comment | added | Anonymous Penguin | @jfpoilpret Oops, didn't notice that. However, it can't hurt to leave it in there. :) | |
| May 4, 2014 at 12:56 | comment | added | Anonymous Penguin | @Chris By balanced I meant that if you combine two slightly different lithium batteries they can be highly dangerous. From what I can tell, the OP is using standard AA alkaline batteries which I am positive that one can't support two amps at a time. Even if it could, it most likely wont last twenty minutes because of voltage loss in the battery. There is no chip to manage voltage loss. The OP hasn't specified the battery composition they are using, either, so it may be able to supply enough current, if charged enough. | |
| May 4, 2014 at 6:51 | comment | added | jfpoilpret | There is already a 100uF cap shown on the circuit, so why mentioneing that adding a cap is needed? | |
| May 4, 2014 at 4:43 | comment | added | Chris Stratton | Please stop giving mistaken advice about batteries. Most cells can supply a current many times their mAh rating, by a factor of 10 or more (the C rating). "Balance" is largely a charging concern, and primarily with lithium chemistries - something neither a 9.6v RC pack nor individual 1.2 - 1.5v AA cells utilize. | |
| May 4, 2014 at 1:59 | comment | added | Anonymous Penguin | @Paul No, this is a common misconception. A mAH means that it has the capacity to release that much power, not that it can release that all at once. Since it's hard to tell the maximum current on most one-time batteries, I'd recommend getting a 9.6V rechargeable "RC battery" that can provide 1.8+A (amps, not amp hours). They can get a bit costly, but you need that much power. Advice: don't try adding rechargeable batteries in series. They're highly dangerous if not perfectly "balanced!" | |
| May 4, 2014 at 1:10 | comment | added | Paul | I just tried increasing the delay time to 1000ms (1 second), and still no change in behavior. I guess I'll have to try batteries that can provide higher amperage. I looked up my AA batteries and found that they provide about 900 milliamp-hours. Should I look for batteries that provide at least 1700 milliamp-hours (corresponding to the 1.7amp current draw from the stepper motor)? | |
| May 3, 2014 at 22:28 | history | answered | Anonymous Penguin | CC BY-SA 3.0 |