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by Brandon92
Sat Feb 16, 2019 2:36 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: MCP3008 SPI at 5V
Replies: 14
Views: 372

Re: MCP3008 SPI at 5V

CE_student wrote:
Sat Feb 16, 2019 11:58 am
I will definitely check out the LE33CZ for future projects like this.
Got everything working smoothly now, thanks for the help!
Good to hear that. How did you connect everything to each other now?
by Brandon92
Fri Feb 15, 2019 8:43 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: MCP3008 SPI at 5V
Replies: 14
Views: 372

Re: MCP3008 SPI at 5V

Thanks for the fast replies. So I was starting to set up a voltage devider for the data output of the humidity sensor when I found following information in the datasheet: VOUT at 75.3% RH (relative humidity) : 3.198V Now I'm thinking, in my use-case the sensor won't measure anything above 70% at ma...
by Brandon92
Fri Feb 15, 2019 7:11 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: MCP3008 SPI at 5V
Replies: 14
Views: 372

Re: MCP3008 SPI at 5V

Yes, you will (slowly) kill your Rpi input. Because it is designed at a maximum input voltage of 3.3v. And it is not designed for 5v at all!
by Brandon92
Tue Feb 12, 2019 6:45 am
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 136
Views: 2649

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

@tlfong01 You can also measure how open or close the n channel is of the MOSFET. You simply need to measure the voltage across the drain and the source. And it should be a very small voltage across it. Because of the low RDS(on) value. So, you can also calculate what the real RDS(on) is at that time...
by Brandon92
Tue Feb 12, 2019 6:38 am
Forum: Automation, sensing and robotics
Topic: Ultrasonic sensor and voltage division
Replies: 19
Views: 403

Re: Ultrasonic sensor and voltage division

Yes, physical the current flow from - to +. But we dicided to make it goes from + to -. To make it easier for or self. (Easier to calculate for example, you don't need to thing much about the - sing.) Anyway, this explanation we use the convention way. So, let's assume that a F1 car is the current a...
by Brandon92
Mon Feb 11, 2019 9:02 pm
Forum: Automation, sensing and robotics
Topic: Ultrasonic sensor and voltage division
Replies: 19
Views: 403

Re: Ultrasonic sensor and voltage division

Well, if you look at the electrons. They indeed move from the (-) to the (+). However, by convention we decide that the current flows from (+) to (-). More info So, in your case, (if we make the input of the Rpi infinity), the current will go from "power supply" -> Echo -> R1 -> R2 -> ground -> "pow...
by Brandon92
Sun Feb 10, 2019 10:41 am
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 136
Views: 2649

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

IRF540N Test Circuit IRF540N Test Circuit - With Rg and Rgs added https://penzu.com/p/087c1ca8 ... Your R2 (1k) has a to low value in comparison to your R1. So, you have made a voltage divider instead. And that is not what you want here. So, you need a higher value of R2. I have used values of 50k ...
by Brandon92
Fri Feb 08, 2019 9:51 pm
Forum: Python
Topic: ACS712+MCP3008 - Need help to convert bit values to current values
Replies: 14
Views: 319

Re: ACS712+MCP3008 - Need help to convert bit values to current values

Maybe you should read that post https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=221972&hilit=acs712 I did explain all the equation there. It will give you what we found about the ACS712, its resolution and the problem with the VCC power. The ACS712 Vout has a VCC/2 offset so you need to rea...
by Brandon92
Fri Feb 08, 2019 4:24 pm
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 136
Views: 2649

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

Your analysis is flawed. That's only true for an unloaded GPIO pin. Assuming the GPIO is ideal is nonsense, and leads to nonsense results like it supplying 2.8A to charge the 1350pf to 3.3V in 1.6nS. That just isn't going to happen ! :roll: The GPIO pin is a voltage source which has a maximum sourc...
by Brandon92
Sun Feb 03, 2019 9:16 pm
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 136
Views: 2649

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

It's a MOSFET, so gate current will be very small until you hit the gate protection diodes (at +10V and -8V from the data sheet) so you can use a larger gate resistor. The only change will be a slightly increased turn-on and turn-off times as the gate capacitance (1350pF from data sheet) will take ...
by Brandon92
Sun Feb 03, 2019 11:52 am
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 136
Views: 2649

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

@Burngate A okay, I thought that you where using a program that generated that. But notepad is indeed usable for this task. And I'm also using Windows :? To give you a little bit on why this gate resistor is needed. As you might know you can turn in a MOSFET with a certain voltage. Rather than a cur...
by Brandon92
Sat Feb 02, 2019 8:55 pm
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 136
Views: 2649

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

I would also add a diode across the solenoid to protect the MOSFET. And a gate resistor is also not a bad idea.

@Burngate
What for kind of program are you using for those diagram?
by Brandon92
Fri Feb 01, 2019 3:58 pm
Forum: General discussion
Topic: MOSFET IRF520
Replies: 8
Views: 278

Re: MOSFET IRF520

I also would advise you not to start with this project. Here are some point why: your question shows us that you don't have much experience in this field do you know the difference between ac and dc? it is not possible to control ac with a single MOSFET. It is a fundamental problem. Yes, there are s...
by Brandon92
Fri Feb 01, 2019 1:13 pm
Forum: General discussion
Topic: MOSFET IRF520
Replies: 8
Views: 278

Re: MOSFET IRF520

vk7017027 wrote:
Fri Feb 01, 2019 1:11 pm
Can I use any other mosfet?
Can you give us more information about the fan (voltage AC or DC and the power)
by Brandon92
Thu Jan 31, 2019 7:01 pm
Forum: General discussion
Topic: Two devices blown up while connecting both 3V3 and 5V power supplies with logic switcher
Replies: 3
Views: 195

Re: Two devices blown up while connecting both 3V3 and 5V power supplies with logic switcher

Did you perhaps connect the 5v to the 3.3v side. And the 3.3v to the 5v side. If you did this, your Rpi will be dead indeed.
by Brandon92
Wed Jan 30, 2019 2:13 pm
Forum: Beginners
Topic: Relay boards
Replies: 31
Views: 2025

Re: Relay boards

I have installed "Wiringpi" and "Wiringpi2" but unfortunately I can't get them to work, But having read all the Internet lots of people are having the same problem it "Wiringpi" Can you give the error that you are getting? And what is currently the issue is? And can you post a diagram, picture of y...
by Brandon92
Tue Jan 29, 2019 8:35 am
Forum: Other
Topic: Raspberry Pi + relay GPIO dont work
Replies: 26
Views: 881

Re: Raspberry Pi + relay GPIO dont work

Dam_Fr wrote:
Mon Jan 28, 2019 11:54 pm
I am trying to use my low cost aliexpress relay to power a 220V motor
What is the specification of your motor? Because you might need a other relay for this task.
by Brandon92
Sun Jan 27, 2019 1:38 pm
Forum: Automation, sensing and robotics
Topic: Buying quality components?
Replies: 6
Views: 344

Re: Buying quality components?

When I want a good IC or other parts, the first place for me is often Farnell. Or I go to the manufacturer side like (Siemens, Omron, Panasonic, Analog devices, Microchip, infinion, taxis instruments, maxin) and some others. But it's also more important that you use the correct part for the job. For...
by Brandon92
Thu Jan 24, 2019 10:39 pm
Forum: Beginners
Topic: Using PWM to slow down a motor
Replies: 8
Views: 238

Re: Using PWM to slow down a motor

I didn't look at your code.
But, what for motor are you using. And how did you connect it to the chip. Because I think that the motor need more power than your hat can deliver. And you probably need a MOSFET to drive your motor. Or a dedicated motor driver controller.
by Brandon92
Thu Jan 24, 2019 10:23 am
Forum: Beginners
Topic: Relay boards
Replies: 31
Views: 2025

Re: Relay boards

Hi kind people, great news, I believe I have managed to get my Pi, mcp23017 and my relay working.... :o BUT it's looking like it's working backwards..... If I give it..0x00 the relay lights come on If I give it 0xff they all go off I thought it was supposed to be the other way round...... How did y...
by Brandon92
Tue Jan 22, 2019 9:22 pm
Forum: Beginners
Topic: Relay boards
Replies: 31
Views: 2025

Re: Relay boards

I'm thinking of giving up on the Raspberry Pi and moving to the Arduino..... :lol: .. I believe that this is done before on this forum. And I unfortunately haven't not the time to search it. But what part is do you have trouble with. Because a arduino and the Rpi is not that big of a different when...
by Brandon92
Mon Jan 21, 2019 5:06 pm
Forum: Automation, sensing and robotics
Topic: Battery state-of-charge measuring ideias
Replies: 4
Views: 265

Re: Battery state-of-charge measuring ideias

Good to hear that you could use the information. And on the website you would probably find more information about the different type that the manufactur has. Did you try it with a I2C multiplexer? Maybe that device can help you with the I2C bus. Strange that that IC will give you that much trouble ...
by Brandon92
Mon Jan 21, 2019 5:01 pm
Forum: Automation, sensing and robotics
Topic: Convert low frequency PWM 1Khz to high frequency PWM 25Khz
Replies: 5
Views: 243

Re: Convert low frequency PWM 1Khz to high frequency PWM 25Khz

You could try to see if the 1kHz is enough for the fan. Otherwise you got a couple options I think:
  • use a other microcontroller, like the one in the arduino
  • try to increase the frequency of PWM in the current microcontroller. Changing some internal registers
  • A PLL with a divider
by Brandon92
Sat Jan 19, 2019 11:29 pm
Forum: Automation, sensing and robotics
Topic: Convert low frequency PWM 1Khz to high frequency PWM 25Khz
Replies: 5
Views: 243

Re: Convert low frequency PWM 1Khz to high frequency PWM 25Khz

I would indeed use a other microcontroller. And this day flashing/ programming a microcontroller is as simple as pressing the right bottum. And you only need to write code that goes into the microcontroller. And you can program it as many times as you want. And is your goal of this protect to make t...
by Brandon92
Sat Jan 19, 2019 10:43 pm
Forum: Automation, sensing and robotics
Topic: Convert low frequency PWM 1Khz to high frequency PWM 25Khz
Replies: 5
Views: 243

Re: Convert low frequency PWM 1Khz to high frequency PWM 25Khz

Maybe a stupid awnser. But why are you using a 1kHz signal as the original one. And not the 25kHz as the basic one. And a 1kHz switch frequency is not high for a buck converter. Normal it is in the order of 100kHz to a couple of MHz. Because it is more efficient at a higher frequency. And the size o...

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