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dlginstructables

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7Instructables946,658Views122CommentsBerkeley, CA
By day I'm a mechanical engineer at a university laboratory. In my free time, I do my own projects.

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  • BLDC Motor Control With Arduino, Salvaged HD Motor, and Hall Sensors

    Hi, thanks for your question. It's been so long that I've forgotten much of what I knew about these motors, but I think I can explain it. From the photo of the sensor assembly, it's clear that the hall sensors are 15° apart. And, from section 4, we know the magnets are 45° apart. Therefore, if you superimpose the sensors over the magnets and then rotate the magnets, every 15° you get a new combination of sensor signals, and the sequence of signals repeats every 90°. I will change 30 to 15 in the text.I'm glad you are benefitting from my work. I spent a ton of time on it back then. Good luck and please let me know how your project turns out.

    Hey, I was wrong. The sensors are 30° apart! But, I think my explanation about the rotation and the sensor signals is correct.

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  • DIY Bicycle Pannier (Saddle Bag)

    Thta's lovely! Thank you for sharing. I hope you get a lot of use out of it. I use mine every day :)

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  • Resurrecting the California Cooler

    Hi,Thank you for your comments and questions. Sorry it took me so long to respond. This is an update that I put in the instructable (it's not in a very visible place and I'm going to move it): Update October 2014We have had the CA cooler for several years now. We still keep the same types of items in it - butter, tomatoes, eggs, some oils, peanut butter. Overall, I would say that it's not worth it for someone remodeling their old house to spend a lot of money resurrecting their CA Cooler, nor to add them to new houses. I think the main lesson we have learned is we can get by with a smaller refrigerator, and I suspect that most households could do the same. That would be a great energy saver, but the trend for a long time has been for households to buy ever larger fridges.Your comment abou…

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    Hi,Thank you for your comments and questions. Sorry it took me so long to respond. This is an update that I put in the instructable (it's not in a very visible place and I'm going to move it): Update October 2014We have had the CA cooler for several years now. We still keep the same types of items in it - butter, tomatoes, eggs, some oils, peanut butter. Overall, I would say that it's not worth it for someone remodeling their old house to spend a lot of money resurrecting their CA Cooler, nor to add them to new houses. I think the main lesson we have learned is we can get by with a smaller refrigerator, and I suspect that most households could do the same. That would be a great energy saver, but the trend for a long time has been for households to buy ever larger fridges.Your comment about a floor-to-ceiling design with air from the basement/crawl space makes all the sense to me. Our basement is pretty much 60°F year round. I like the idea so much, that I've been thinking if there's a way to run some tubing from our crawl space up through the wall space and into the cooler. So, if you are designing from scratch, floor-to-ceiling is the way to go. I'm also going to add this info to the Instructable. Good luck!

    Another thought - maybe you can create a way to use outdoor air when it's cold, and switch to basement air when it's warm outside.

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  • BLDC Motor Control With Arduino, Salvaged HD Motor, and Hall Sensors

    I'm glad you find the Instructable useful. Although I would love to some day, I have never worked with a motor of that much current and voltage. I did put some safety tips in the Instructable, which you might have seen. Before starting, I would thoroughly research safety practices. I can tell you that you need to find components that can handle that much power, you need to properly heat sink the transistors, and, as I said in the Instructable, add an over-current feature. It's not just your personal safety which, of course, is the most important, but careless mistakes can also burn out expensive components. Good luck!

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  • That should not be a problem.

    Yes, it will work with an Arduino uno. To use a 3W motor you may have to get transistors that can work with more power. Other than that, this system should work for that. I have already proven regenerative braking. If you mean "improve", I don't know how to improve the performance of this system. In general, if you are using higher voltage, then the efficiency of the regenerative braking should go up.

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  • There's a photo in step four showing the PVC. That cylinder sticks up into a hole in the bottom of the oven, to keep it from sliding off. It may not be necessary. By the way, I found this lazy susan mechanism to not be very reliable. I've changed to a pulley mechanism and it works much better. Unfortunately, I don't have time to update the instructions right now. The entire box is made of foam, with a cardboard layer inside. The foam is glued together with RTV silicone.

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  • Hi Clifford,You get the amperage by dividing W/V. For example, 200W/24V = around 8 A. I would get that the chip in my project can't handle that, but take a look at the data sheet. If it won't, you'll have to find another driver that can, and adapt the project to it. Just be careful with safety precautions, because you could injure yourself, and/or blow out your components pretty easily.

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  • Hi Aaron,That's great that you got your motor working! Yes, it could be an over-temperature sensor that is stopping it, so I would try heat sinking. Also,you could be exceeding the current or voltage specs of the driver. Look on the data sheet for the maximum ratings. I think you just need to use ohm's law to figure out the current you need. First, measure the resistance of one of the motor phases. For example, if the phase is 10 ohms, then I = 24/10 or 2.4 Amps.

    Hi Capo.Ferrari,The instructable already has instructions for the regenerative braking.

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  • Hi,That sounds like a very interesting project. I have no experience with RC, but in terms of motor control, yes, I believe an Arduino (16 MHz clock speed) could handle controlling two motors at the same time. I suppose you would alternate the commutation between the two motors, and your algorithm would vary the motor speeds depending on the position of the joystick. Good luck!

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  • I don't think the Arduino would have any trouble with that, but you would want to beef up the power electronics.I don't think the L6234 could handle those kinds of currents/voltages (look at the datasheet to be sure).If you do start working with larger motors, be sure to educate yourself on the safety issues involved, both for your own safety, and for the care of the electronics components.

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