So, you’re wondering about the L293D just right off the bat? Search for some quick information on it, eh? Well, well, this is what I found out.
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Indeed, this chip is available from Digikey.
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The chip is also available from Adafruit, and they have a nice product information page on it for beginners who are not super skilled in electronics.
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The chip is in fact a dual H-bridge integrated circuit. No magic involved in its design.
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You can also use the L293D to control stepper motors and solenoids. In the case of solenoids, 4 can be controlled with one motor control unit.
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There is a built-in inductive kick-back protection diode, of course.
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On the other hand, that means for motors that guard voltage regulators and diodes may still be required, in case the motor gets turned externally and runs in “generator-mode.”
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PWM input can be used to modulate the motor speed.
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The L293D won’t work well with 3 V motors, unfortunately. Yes, you can use it to control 3 V motors, but it won’t work very well. Okay, that’s it. Some of the most important motors I have to control are 3 V motors.
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That being said, I better actually go searching for a motor controller that is good for controlling 3 V motors. As a nice plus, if it also runs off of 3 V logic, I can control my whole system using only 3 V power. Then, 5 V are only needed for USB and HDMI, which are purportedly only in used if you are “docked” to systems that have line power available.
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Perfboard friendly through hole chips are preferred over surface-mount PCB chips.
20181119/DuckDuckGo L293D
20181119/https://www.digikey.com/product-detail/en/stmicroelectronics/L293D/497-2936-5-ND/634700
20181119/https://www.adafruit.com/product/807
So, a cursory search for 3 V motor controllers brings up this. And apparently there is an LM293D IC that can be used to control 3 V motors. Ah, so just a simple variation on the L293D is all that is needed. But looks like that runs off of 5 V too.
20181119/DuckDuckGo 3v motor control ic
20181119/https://thecustomizewindows.com/2015/08/arduino-3v-dc-motor-control-transistor-ic-more/
20181119/https://www.ti.com/store/ti/en/p/product?p=LM293D
20181119/http://www.ti.com/lit/ds/symlink/lm293.pdf
Ah, I found something really promising here. Yes, indeed there are motor drive ICs that operate off of only 3.3 V, and here is one of them as an example. Although, if you look at the date of the article, 2017-11-20, these integrated circuits are decidedly quite recent and new. By contrast, if you’re content with 5 V supply voltage, you can choose from a long line of ICs that have been around for quite some time.
20181119/DuckDuckGo 3v motor drive ic
20181119/https://www.elektormagazine.com/news/3-phase-driver-ic-switches-bldc-mosfets
Also interesting. As of very recently, 2018-11-05, optical gyros are now available in a miniature form factor that can be used in smartphones and tablets. Previously an optical gyro was no smaller than a golf ball, so they were not used in those applications. Conventional gyros are micro electrical mechanical systems (MEMS) that take measurements off of small vibrating weights inside. The primary advantage of optical gyros is that they are more accurate than MEMS gyros. But what about the cost? Well, for now let’s assume that is tentative. Purportedly the devices should be cheap simply because they are small integrated circuits.
20181119/https://www.elektormagazine.com/news/optical-gyro-dwarfed-by-a-grain-of-rice
Also another interesting thing here. A kit to get you setup using an ePaper display on a Raspberry Pi. What is the main advantage of ePaper over LCD displays? ePaper doesn’t require power to refresh it. Therefore, the controlling computer can power itself off until the contents of the display need to be changed.
20181119/https://www.elektormagazine.com/news/papirus-epaper-for-raspberry-pi