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Author Topic: Using L292 - ST as a driver for DC motor.  (Read 1571 times)
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I went to the electronics store to buy a L298-N H bridge chip, and they told me they don't have it. I asked whether they had another similar chip that does the same thing (I expected less power or more power, different voltages, but same functionality). They recommended L292, I paid almost $10 for it, went home and found almost no record of it being used by hobbyists on their projects. It looks like a very old, specialized part that's meant to be used along with L290 and L291 on some motor positioning systems, but the manual says it "can" be controlled directly by a microprocessor too (that would be atmega328 for me) but I have no idea of how I should go about it.

I just want to control simple 1A DC motor : forward, reverse and off .

http://www.datasheetcatalog.com/datasheets_pdf/L/2/9/2/L292.shtml

PS - They won't accept it back, they said  so from the beginning. I hope somebody will be kind enough to share some knowledge and save the chip from being smashed to pieces smiley)
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I went to the electronics store to buy a L298-N H bridge chip, and they told me they don't have it. I asked whether they had another similar chip that does the same thing (I expected less power or more power, different voltages, but same functionality). They recommended L292, I paid almost $10 for it, went home and found almost no record of it being used by hobbyists on their projects. It looks like a very old, specialized part that's meant to be used along with L290 and L291 on some motor positioning systems, but the manual says it "can" be controlled directly by a microprocessor too (that would be atmega328 for me) but I have no idea of how I should go about it.

I just want to control simple 1A DC motor : forward, reverse and off .

http://www.datasheetcatalog.com/datasheets_pdf/L/2/9/2/L292.shtml

PS - They won't accept it back, they said  so from the beginning. I hope somebody will be kind enough to share some knowledge and save the chip from being smashed to pieces smiley)

Personally, I think you got sold a pig-in-a-poke; you might just have to consider it a $10.00 lesson learned (been there, done that)...

The thing about this chip is that it looks like only a singular part of a 3-chip solution (the other parts being the L290 and L291, as you've noticed - along with more than a handful of other components, including some kind of encoder). That is for a closed-loop solution (aka - servo positioning).

If you wanted to -attempt- an open-loop (no encoder) solution, and this is based on a really quick "overview" of the datasheet (I could be completely wrong here), I would hook the motor up according to the diagram in figure 5 on page 6. You would then have to do something tricky, because in order to get the motor to spin, you have to supply VI with a voltage between (approx) -9 volts to +9 volts; presumably (?), at 0 volts, the motor doesn't spin; but at one extreme it spins one way, and at the other, it spins the other way. The L290 and L291 are the auxiliary chips that facilitate this normally, but you'll have to do it with a couple PWM control pins on the Arduino, plus a "half-bridge" and a dual-ended power supply supply + and - 9 volts (think of two 9 volt batteries connected in series for 18 volts - if you "tap" the middle connection and make that the "ground" reference for the bridge, then you now have a +9 volt side and a -9 volt side; whatever you do, though, don't mix this ground with any other ground!).

A "half-bridge" is simply that - its half of an h-bridge that can be used to control a DC motor in both directions, with the caveat that it needs a dual-ended power supply. The old Milton Bradley Big Track used such a system for its motors; it had a 6 volt battery made of 4 D-cells, tapped in the middle for the 3 volt motors (the big drawback was that if you made too many turns in one direction, that half of the battery would go "flat" quicker than the other half, and weird self-charging action would occur, which would run down all the batteries really quickly - let's just say as a kid, my parents made Duracell a mint). The bridge can be made using small signal transistors (2n2222 and 2n2907 for instance would be OK, I think).

You would use the PWM to "effect" a variable +/- 9 volts (also - only run one side or the other - never both at same time!) to the bridge, which would send a voltage to VI on the L292 (pin 6).

Also note that since this is a multiwatt 15 package (same as the L298) - it won't fit in a regular breadboard or prototyping PCB with 0.1" spaced holes; you'll need an adaptor PCB (http://www.jrhackett.net/L298brdInfo.shtml - note that this is for the L298, but could be used for this part, as long as you ignore the silkscreen on the PCB adaptor) or a custom PCB for it.

Personally - I think this is all a lot of work for little gain; you'd be better off putting that part away into your "junk drawer" for a rainy day, and purchasing a more appropriate part.

Good luck.

smiley

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Hi cr0sh,

Thanks for your input and time! I never expected anybody to answer anytime soon smiley You're probably very right about putting that component in the "junk" drawer. I'm going to try what you suggested first though.


Thanks a million!
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Hey cr0sh,

Pig in a poke it was! The damn thing doesn't want to do anything. I tried just like you said (I had tried the exact same thing before but followed your instructions just to be sure) and it doesn't do anything. Well, that's a lesson learned! By the way I really appreciate you taking the time to reply. Thanks!
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