Timeline for How to get a constant 5 V power supply when using the same power supply for motors and micro controllers
Current License: CC BY-SA 4.0
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| Apr 2, 2023 at 21:06 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Mar 2, 2023 at 6:15 | answer | added | Simon Fitch | timeline score: 1 | |
| Mar 2, 2023 at 1:25 | history | edited | ocrdu | CC BY-SA 4.0 |
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| Mar 2, 2023 at 1:03 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
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| Jun 5, 2020 at 12:33 | comment | added | Lundin | Sounds like EMC issues originating from the motor signals rather than anything else. Unless you get a voltage surge each time you start the motor? In that case, you might need something more intricate than a stone age 7805. Start by adding a big bulk electrolyte cap directly after the battery. | |
| Jun 5, 2020 at 12:26 | comment | added | Simon B | Some people who are more familiar with this problem may know better than me, but it strikes me that when the motor starts, it can drain C1 as well as causing the battery to dip. Would a (Schottky) diode between the battery and C1 help? | |
| Jun 5, 2020 at 12:19 | answer | added | Ilya | timeline score: 1 | |
| Jun 5, 2020 at 10:15 | comment | added | winny | You need decoupling on your MCU. Start with 100 nF ceramic and see if that helps. Your 7805 may have too much dropout depending on your MCU brownout setting. | |
| Jun 5, 2020 at 9:53 | comment | added | Chris Stratton | Replace the nodemcu with an ESP implementation that can regulate from the battery directly to 3v3. While you are at it replace the horrible L298 with an FET bridge. And consider that wifi isn't really suited to this, simpler 2.4 GHz GFSK solutions line the nRF24L01+ are typical in RC gear. | |
| Jun 5, 2020 at 9:49 | comment | added | Debarshi Das | MCU resets when motors are enabled. I don't have any ceramic capacitors in my circuit. Also, my battery pack contains 2 18650 lithium cells producing approx 8v. | |
| Jun 5, 2020 at 9:37 | comment | added | Andy aka | Please explain how many cells are in your 8 volt battery. | |
| Jun 5, 2020 at 9:09 | comment | added | akwky | Hi! Can you describe when exactly does your MCU reset? Is it all the time, only when the drivers are connected, or only after it enables the motors? Does your MCU also have ceramic (i.e. 100nF) decoupling capacitors besides the big ones shown in the schema? | |
| Jun 5, 2020 at 8:56 | comment | added | Debarshi Das | Schematic added. | |
| Jun 5, 2020 at 8:56 | history | edited | Debarshi Das | CC BY-SA 4.0 |
added 270 characters in body
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| Jun 5, 2020 at 8:03 | comment | added | winny | Welcome to EE.SE! Please draw a block diagram or even better a schematic. There is a built in schematic editor here if you click on edit and the schematic symbol. It sounds like you are suffering from the very common lack of decoupling and/or bad layout. Please show your layout. Also, please note that there is no voltage load from motors (in any normal sense), only current load, or just load in normal speaking terms. | |
| Jun 5, 2020 at 8:01 | review | First posts | |||
| Jun 5, 2020 at 8:43 | |||||
| Jun 5, 2020 at 7:56 | history | asked | Debarshi Das | CC BY-SA 4.0 |