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by tlfong01
Wed Feb 27, 2019 8:07 am
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 156
Views: 9006

Re: Resistors and MOSFETs and fire-prevention, oh my

DSP Sig Gen 1Hz 50% duty cycle driving motor and solenoid, and 1kHz motor only 1kHz signal input to Power MOSFET IRL540N, Rg 470Ω, Rgs 4k7, Vcc 12V, Rload 5Ω 20W Now I tested a 5 resistor 20W, and found everything OK. Power MOSFET IRL540N, Rg 470Ω, Rgs 4k7, Vcc 12V, Rload 5Ω 20W The hardware setup ...
by tlfong01
Wed Feb 27, 2019 8:02 am
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 156
Views: 9006

Re: Resistors and MOSFETs and fire-prevention, oh my

tlfong01 wrote:
Tue Feb 26, 2019 3:01 pm
DSP Sig Gen 1Hz 50% duty cycle driving motor and solenoid, and 1kHz motor only

1kHz signal input to Power MOSFET IRL540N, Rg 470Ω, Rgs 4k7, Vcc 12V, Rload 5Ω 20W

Now I tested a 5 resistor 20W, and found everything OK.

...
by tlfong01
Wed Feb 27, 2019 4:48 am
Forum: Automation, sensing and robotics
Topic: Connecting electromagnet to pi
Replies: 94
Views: 3963

Re: Connecting electromagnet to pi

You might like to refer to my power MOSFET switch schematic below. You can just replace the MOSFET by a relay, and everything "should" work. Controlling Solenoid By High Level Trigger 5V Relay KY019 Or check out my old post below: Relay KY019 Switching Solenoid https://www.raspberrypi.org/forums/vi...
by tlfong01
Wed Feb 27, 2019 4:40 am
Forum: Automation, sensing and robotics
Topic: Connecting electromagnet to pi
Replies: 94
Views: 3963

Re: Connecting electromagnet to pi

tlfong01 wrote:
Wed Feb 27, 2019 3:48 am
You might like to refer to my power MOSFET switch schematic below. You can just replace the MOSFET by a relay, and everything "should" work.

Duplicated Post - My Apologies

Should have posted the one following this one.
by tlfong01
Wed Feb 27, 2019 4:37 am
Forum: Automation, sensing and robotics
Topic: Connecting electromagnet to pi
Replies: 94
Views: 3963

Re: Connecting electromagnet to pi

I also have a 10A, 45V diode that I will be using for flyback. Flyback Diode Selection Your diode spec of 10A 45V sounds like a power rectifier which usually switches at low 50/60Hz mains frequency. For flying back you must use a high speed switching guy. See my references below: Flyback Diode Sele...
by tlfong01
Wed Feb 27, 2019 3:48 am
Forum: Automation, sensing and robotics
Topic: Connecting electromagnet to pi
Replies: 94
Views: 3963

Re: Connecting electromagnet to pi

1. I want to control with Rpi electromagnet 12V, 2Ω, 6 A. 2. I have a 12V relay board that I connected to the pi. 3. I'm not sure how to set up the circuit. Cheap 5V Relay can control DC 6/12/24/36V 8A, AC 6/12/24/110/220, 8A 2. You don't need a 12V relay to switch a 12V load. You can use a cheapy ...
by tlfong01
Wed Feb 27, 2019 2:30 am
Forum: Automation, sensing and robotics
Topic: Connecting electromagnet to pi
Replies: 94
Views: 3963

Re: Connecting electromagnet to pi

I built the magnet myself ... to run 12V, 2Ω, 6A. DC12V 0.25A 3W Electromagnet Can Lift/Hold 2.5kg Let me see. If 12V, 0.25A, 3W can lift 2.5kg, and power is proportional to square of current, your 6A should be able to lift (6 * 6) / (0.25 * 0.25) * 2.5kg = 1,440kg! Are you sure you want to lift th...
by tlfong01
Tue Feb 26, 2019 3:01 pm
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 156
Views: 9006

Re: Resistors and MOSFETs and fire-prevention, oh my

Rpi GPIO Pin 11 3.0V (Voh) Driving IRL540N Test The circuit with the 14D471K (MOV) metal oxide varister seems problematic. I found the 3.5 yaun IRL540N fried . I removed the varister and replaced another IRL540N and found everything OK again. DSP Sig Gen 1Hz 50% duty cycle driving motor and solenoi...
by tlfong01
Tue Feb 26, 2019 7:16 am
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 156
Views: 9006

Re: Resistors and MOSFETs and fire-prevention, oh my

Next is to check out if Rpi can indeed direct drive IRL540N with GPIO 3V signals. Rpi GPIO Pin 11 3.0V (Voh) Driving IRL540N Test Update 2019feb26hkt1709 The circuit with the 14D471K (MOV) metal oxide varister seems problematic. I found the 3.5 yaun IRL540N fried. I removed the varister and replace...
by tlfong01
Tue Feb 26, 2019 7:08 am
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 156
Views: 9006

Re: Resistors and MOSFETs and fire-prevention, oh my

OK I have to ask, is tlfong01 some sort of weird automated BOT designed to analyse posts and then make up almost related responses, but not quite correct because a BOT doesn't truly understand what it is reading? :?: :mrgreen: But I am very serious when trying to point out that many electronic prod...
by tlfong01
Mon Feb 25, 2019 1:29 pm
Forum: Automation, sensing and robotics
Topic: Choosing motors
Replies: 36
Views: 3133

Re: Choosing motors

My robot will use 4 motors for 4 wheels. TB6612 Motor Driver Module You might also like to consider motor driver modules. I would recommend the cheapy TB6612 motor driver module. Like AdaFruit, SparkFun gives very good tutorials, but their stuff is a bit expensive. :mrgreen: SparkFun TB6612 Motor D...
by tlfong01
Mon Feb 25, 2019 12:25 pm
Forum: Automation, sensing and robotics
Topic: Choosing motors
Replies: 36
Views: 3133

Re: Choosing motors

Vgs 5V 1kHz 5% Duty Cycle Square Wave Driving Vcc 12V IRL540N with RS130 3~6VDC Motor DC Motor Characteristics Geared motor seems to take smaller current than no gear motor. I am a little bit confused. I only remember the DC motor characteristics is a bit difficult to understand. So I read my old d...
by tlfong01
Mon Feb 25, 2019 9:24 am
Forum: Automation, sensing and robotics
Topic: Choosing motors
Replies: 36
Views: 3133

Re: Choosing motors

Post #2, stepper motors with gearboxes for £1.54? How physically small, how much torque possible from them? I'd be interested to know for future projects of my own. Second Hand, Taken-Out-From-Machines Stepping Motors When I first learnt how to play with stepping motors, I bought a couple from TaoB...
by tlfong01
Mon Feb 25, 2019 7:54 am
Forum: Automation, sensing and robotics
Topic: Choosing motors
Replies: 36
Views: 3133

Re: Choosing motors

Rpi 3V GPIO Direct Drive 12V IRL540N PWM DC3-6V TT Motors I guess 12VDC low duty cycle PWM can drive 3-6VDC motor with little risk of frying any. Just in case, I have loads of cheap, CN¥ 0.5 motors standing by to fry! :mrgreen: Vgs 5V 1kHz 5% Duty Cycle Square Wave Driving Vcc 12V IRL540N with RS13...
by tlfong01
Mon Feb 25, 2019 6:41 am
Forum: Automation, sensing and robotics
Topic: Choosing motors
Replies: 36
Views: 3133

Re: Choosing motors

Those TT motors are the best value for hobby bots, good to learn on. And once those cheap motors wear out you can replace them with lower current, higher voltage 12V ones. Rpi 3V GPIO Direct Drive 12V IRL540N PWM DC3-6V TT Motors I guess 12VDC low duty cycle PWM can drive 3-6VDC motor with little r...
by tlfong01
Mon Feb 25, 2019 5:24 am
Forum: Automation, sensing and robotics
Topic: Choosing motors
Replies: 36
Views: 3133

Re: Choosing motors

The robot should be able to drive really straight, so sometimes it has to travel 1 meter and should stay on the exact line and not change its orientation. It should also be able to do this if there is more weight on one wheel, because of an uneven ground. If possible it should also be affordable. M...
by tlfong01
Mon Feb 25, 2019 4:26 am
Forum: Automation, sensing and robotics
Topic: Choosing motors
Replies: 36
Views: 3133

Re: Choosing motors

Those TT motors are the best value for hobby bots, good to learn on. And once those cheap motors wear out you can replace them with lower current, higher voltage 12V ones. DC3V TT Motors and DC12V N20 Motors Yes, my plan is to upgrade to 12V motor later for the following reason. I am playing with p...
by tlfong01
Mon Feb 25, 2019 2:03 am
Forum: Automation, sensing and robotics
Topic: Choosing motors
Replies: 36
Views: 3133

Re: Choosing motors

DC brush motors have a mechanical clutch DC motors with good gearboxes and a tacho (magnetic or opto) sensor Sumo bots have very sticky wheel treads and low duro rubber tires A new way of compensating is with motion sensors, optical mouse type positioning. I hate DC motor gear noise and I'm looking...
by tlfong01
Sun Feb 24, 2019 2:08 pm
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 156
Views: 9006

Re: Resistors and MOSFETs and fire-prevention, oh my

HobbyComponents IRF520 MOSFET Driver Module Model HCMODU0083 - £2.5 https://hobbycomponents.com/motor-drivers/661-irf520-mosfet-driver-module This little module is a breakout board for the IRF520 MOSFET transistor. The module is designed to switch heavy DC loads from a single digital pin of your mi...
by tlfong01
Sun Feb 24, 2019 9:34 am
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 156
Views: 9006

Re: Resistors and MOSFETs and fire-prevention, oh my

tlfong01 wrote:
Sun Feb 24, 2019 8:27 am

CSD18511KCS Test Results

I checked out 10 pieces and found all Rpi 3V3 GPIO signals compatible.
...
by tlfong01
Sun Feb 24, 2019 8:27 am
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 156
Views: 9006

Re: Resistors and MOSFETs and fire-prevention, oh my

Keyes IRF520 Power MOSFET Driver Module I saw TaoBao selling fake IRF520 modules at ¥3 each . So I bought 10 for testing. :mrgreen: HobbyComponents IRF520 MOSFET Driver Module Model HCMODU0083 - £2.5 https://hobbycomponents.com/motor-drivers/661-irf520-mosfet-driver-module This little module is a b...
by tlfong01
Sun Feb 24, 2019 7:33 am
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 156
Views: 9006

Re: Resistors and MOSFETs and fire-prevention, oh my

tlfong01 wrote:
Sun Feb 24, 2019 3:33 am
This morning I started testing 30 power MOSFETS:
.....(a) 1.2 yuan URL540N x 10,
.....(b) 3 yuan IRF540N x 10,
.....(c) 3.5 yuan IRL540N x 10.


1.2 yuan IRL540N x 10 Results Bad - Rpi GPIO 3V3 signal Not Compatible, But still useful if Vgs >= 5V

...
by tlfong01
Sun Feb 24, 2019 7:27 am
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 156
Views: 9006

Re: Resistors and MOSFETs and fire-prevention, oh my

tlfong01 wrote:
Sun Feb 24, 2019 3:33 am
This morning I started testing 30 power MOSFETS:
.....(a) 1.2 yuan URL540N x 10,
.....(b) 3 yuan IRF540N x 10,
.....(c) 3.5 yuan IRL540N x 10.


3.5 yuan IRF540N x 10 Results OK - But Rpi GPIO 3V3 signal Not Compatible

...
by tlfong01
Sun Feb 24, 2019 7:21 am
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 156
Views: 9006

Re: Resistors and MOSFETs and fire-prevention, oh my

tlfong01 wrote:
Sun Feb 24, 2019 3:33 am
This morning I started testing 30 power MOSFETS:
.....(a) 1.2 yuan URL540N x 10,
.....(b) 3 yuan IRF540N x 10,
.....(c) 3.5 yuan IRL540N x 10.


3.5 yuan IRL540N x 10 Results Good - Rpi GPIO 3V3 signal OK

...
by tlfong01
Sun Feb 24, 2019 3:33 am
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 156
Views: 9006

Re: Resistors and MOSFETs and fire-prevention, oh my

If the fet is getting hot then it is probably in the analog region. A higher gate voltage turns it on more and so the resistance goes lower and hence heat goes down. theitguyfromny » 2019-Feb-08 Fri 9:15 am The FET was getting real hot before (too hot to touch), but not w/ the set up I have now, I ...

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