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pico esc bldc

PI PICO OUTPUT PEN PROTECTION FROM REVERSE VOLTAGE

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I am running a BLDC motor with Rasberry Pi PICO using DShot ESCs. Everything is good well when I run 1 or 2 motors. However when I try to run 4 motors at the same time. It fries my PICO. It seems motors or ESC is producing a reverse voltage which flows back and fries my PICO. I tried a number of Diodes but some are distorting the frequency and some don’t work at all. The Diodes I used

  1. FR302 : passes signal but distorts it makes motors to vibrate and make noise
  2. IN4148: doesnt work
  3. 1N5819: Schottky : just bought going to test them
  4. UF4003: just bought going to test them DSHOT are very high frequency ESCs and I am passing signal in KHz. So I need a Diode that stops voltage from one side but let the signal go undistorted and without any delay. or any other solution. see the image, battery powers up both RPI4 and ESC. then RPI is used to powerup PICO and PICO sends speeds to ESC. PICO and ESC is connected through 5 wires, a ground and 4 motor speed signals. ESC controls the motors. Thanks
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edited 19 hours ago

asked 21 hours ago

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ZAK

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  • 1. Try 1kHz < f < 5kHz, 2, 1N4148 is signal guy, not Schottky. 3. 519 is OK. I like it. 4. BLDC is easy to fry: electronics.stackexchange.com/questions/514793/…. Good luck. – tlfong01 20 hours ago   
  • Thank @tlfong01 I will try the 5819 first then. – ZAK 20 hours ago
  • also what about Zener Diode. Are they any good in this scenario ? – ZAK 20 hours ago
  • Where is the circuit diagram? – joan 19 hours ago
  • @Joan thanks , please see the question I just added the circuit diagram with a bit of description. Hope the basics are right 🙂 – ZAK 19 hours ago
  • 1If you only connect to the ESC control inputs there should be nothing coming back to the pico from the motors. – joan 19 hours ago
  • @ZAK: (1) Zener is to get a stabilized reference voltage, eg in regulated power supply. (2) You might find the following useful: Back EMF Flyback Diode Selection Notes – rpi forum 2019ja17 forums.raspberrypi.com/… – tlfong01 18 hours ago  
  • One more thing – I don’t know anything about DShot ESC. So my suggestions might be silly. What is DShot ESC Protocol? – 2016nov08 oscarliang.com/dshot – tlfong01 18 hours ago   
  • Thanks @tlfong01 so its means they wont work for me. Thanks – ZAK 17 hours ago
  • @joan PICO is only connected to ESC and RPI and only ESC got that much power to fry a PICO so the main point of investigation atm. DSHOT protocol is digital protocol to replace old analog ones. Mainly concerned with how to pass data from MCU to an ESC. Where DShot (ESC) got its own MCU to interpret the input and forward it to motors. So the protocol in itself has nothing to do with my problem. – ZAK 17 hours ago
  • @tlfong01 looking at the diagram do you think putting a diode btween PICO and ESC will solve my problem? like in case voltage is flowing towards the pico then will stop it and also not affect the outward frequency ? My main question here is Diode can pass KHz of frequency without rectifying (changing/distorting) it towards ESC ? – ZAK 17 hours ago
  • There is nothing wrong according to the diagram. I suggest you post photos so we can check that the implementation corresponds to the diagram. – joan 17 hours ago 
  • @joan so if I understand you are saying I dont need Diodes ? The strange thing is, sometimes it works properly even with 4 motors and always works with 2 motors. So I thought it might be because 4 motors pushing back more voltage towards PICO and frying it. However if you think I need diodes could you suggest the part number ? thanks – ZAK 16 hours ago
  • @tlfong01 tested 1N5819 they dont work…seems blocking the whole signal from PICO to ESC. – ZAK 16 hours ago
  • 1I am saying we don’t know if you have done anything wrong or not. We need more information. – joan 16 hours ago
  • A coouple of questions: (1) BLDC motor usually has one than one input signal. So yours don’t seem to be BLDC, but just DC motor. (2) You battery might only be strong enough to drive two motor and not more. (3) Flyback diodes usually connect to motor side, no input signal side. – tlfong01 13 hours ago  
  • 1@tlfong01 (1) I didn’t show in the diagram but each motor is connected to ESC using 3 wires. so they are BLDC (2) It can be a reason however it works sometimes, which makes things worse to solve the problem (4) Make sense, however it will keep the ESC safe from motors but not sure if PICO is affected by ESC leaking and not directly from motors. Like if ESC decides to stop / reduce the voltage to reduce the speed then the riffle effect of the voltage goes to the PICO ? T – ZAK 1 hour ago 
  • The interesting thing is….I removed all the Diodes and its working fine now (again). But still want to know the reason behind as it makes the whole system unpredictable. I say its working fine because before frying PICO one of the motor gets desync (vibrate/gets noisy or doesn’t run at all), which it is not doing atm. – ZAK 56 mins ago 
  • @ZAK: (1) So your one wire is in fact three wires. (2) Perhaps you can give us the links to your ESC and BLDC motor. – tlfong01 55 mins ago  
  • 1@tlfong01 no sorry, there are 3 wires to each motor from ESC to a motor. links for ESC and motors are hobbywing.com/goods.php?id=653 or aliexpress.com/item/… and motors aliexpress.com/item/… – ZAK 50 mins ago
  • 1and I am using a 4 cell Lipo battery with upto 16v . – ZAK 49 mins ago 
  • Many thanks for the links: (1) XRotor Micro 60A 4in1 BLHeli-32 DShot1200 (Overview, Spec) – HobbyWing hobbywing.com/goods.php?id=653 (2) Hobbywing XRotor Micro 60A 4 en 1 BLHeli-32 DShot1200 3-6S ESC pour drone de course FPV Quadcopter US$61 – AliExpress fr.aliexpress.com/item/… (3) XRotor Micro 60A 4in1 BLHeli-32 DShot1200 (User Manual) – HobbyWing hobbywing.com/products/enpdf/XRotorMico60ADShot1200en.pdf / to continue, … – tlfong01 2 mins ago  Edit  
  • /Continued, … (4) GARTT 4pcs/6pcs ML 3515 400KV Brushless Motor for QAV Quadcopter Multicopter RC Drone ()With Spec)- AliExpress US$118 4PCS fr.aliexpress.com/item/… – tlfong01 1 min ago  Edit  

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