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by Brandon92
Fri Feb 14, 2020 8:21 pm
Forum: General discussion
Topic: Which resistor and diode to use ?, for tip120 for 24v solenoid valve.
Replies: 14
Views: 423

Re: Which resistor and diode to use ?, for tip120 for 24v solenoid valve.

I'm also more in EE than in linux ;) but there are indeed different opinions in the field. What is a good thing, then we can learn from each other :) BTW by 'high' I mean UHF/VHF not low frequency ringing shown in those traces you posted. I see a huge round pulse using FETs with far less ringing. Is...
by Brandon92
Thu Feb 13, 2020 10:23 pm
Forum: General discussion
Topic: Which resistor and diode to use ?, for tip120 for 24v solenoid valve.
Replies: 14
Views: 423

Re: Which resistor and diode to use ?, for tip120 for 24v solenoid valve.

O boy, here we go again ;) :) As told before it is not only about he switching element. IDK about that. The diode, while it may protect a poorly chosen old tech transistor, actually generated measurably more UHF noise in recent tests compared to no diode at all. Those sharply clipped spikes have muc...
by Brandon92
Thu Jan 30, 2020 9:27 pm
Forum: General discussion
Topic: Control 8 Nema 17 stepper motor with A4988 driver using raspberry pi 3B
Replies: 7
Views: 1798

Re: Control 8 Nema 17 stepper motor with A4988 driver using raspberry pi 3B

Hello, First of all, which part of this project do you already know. Or are you a complete beginner to this? And did you already buy the parts for this project. If you did, can you provide more information about this (link to the website, ect). Then we can start from there :) Hi, link is not seen. ...
by Brandon92
Sat Jan 25, 2020 7:35 pm
Forum: Beginners
Topic: 120V Source to GPIO pin question
Replies: 7
Views: 361

Re: 120V Source to GPIO pin question

Does your automatic door opener has a "output" to drive something else or give a signal. I know that our one can give a 24Vdc output signal in different situations. If you don't have (high voltage) electronics knowledge, than one of the easiest solution is to use a phone charger with a voltage divid...
by Brandon92
Tue Jan 14, 2020 8:50 pm
Forum: Automation, sensing and robotics
Topic: WashbearyPi - Controlling a washing machine with a Pi
Replies: 12
Views: 1606

Re: WashbearyPi - Controlling a washing machine with a Pi

I would advice you to use a low pas filter in front of the comparator (or at his output) that would filter out the high frequency noise and other crap. However there is already some filtering, because of the transformer. When you use a window comparator you could set it to 1V and -1V. You get a a pu...
by Brandon92
Sun Jan 12, 2020 7:01 pm
Forum: Automation, sensing and robotics
Topic: WashbearyPi - Controlling a washing machine with a Pi
Replies: 12
Views: 1606

Re: WashbearyPi - Controlling a washing machine with a Pi

The design of a zero-crossing detection circuit is just work in progress. My first version will use a transformer (230V AC -> 15 V AC), a voltage divider and a comparator IC. It is quite likely that the transformer will generate a slight phase shift. However, if the phase shift is constant for all ...
by Brandon92
Wed Jan 08, 2020 8:57 pm
Forum: Beginners
Topic: How to control 14 AC LED dimerable spots
Replies: 4
Views: 187

Re: How to control 14 AC LED dimerable spots

I could build a dimer for the 110V LED spots, but would need some project or guide to better understand how. Should be used solid state relays? or some circuit with TRIAC? Thanks for the Philips Hue project, but in my case I will have to use regular dimerable LED spots. Well, dimming a led is not t...
by Brandon92
Tue Jan 07, 2020 9:08 pm
Forum: Beginners
Topic: How to control 14 AC LED dimerable spots
Replies: 4
Views: 187

Re: How to control 14 AC LED dimerable spots

I assume that you can not make your own AC LED driver, because you are asking here. And no, it is a easy task to dim a LED lamp. So maybe you are looking for a more "finished" project like. For example control Philips Hue lamps by a raspberry pi: https://domoticproject.com/controlling-philips-hue-li...
by Brandon92
Tue Dec 24, 2019 7:34 pm
Forum: Troubleshooting
Topic: Relay won't flip
Replies: 40
Views: 1204

Re: Relay won't flip

True. I should not have overlooked davidcoton's comment on that early in this thread. Probably because I've personally had less experience with the RFI side of this than the voltage issue. I'm obsessed with power and relay tech and as a ham RF too. Not so much regarding the PI though. Not yet anywa...
by Brandon92
Tue Dec 24, 2019 5:50 pm
Forum: Troubleshooting
Topic: Relay won't flip
Replies: 40
Views: 1204

Re: Relay won't flip

If we assume a 10x flyback as shown in your pics then 30v generated from a 3v coil would be no problem with that 60v or 400v fet I recommend. Or even the 45v spec for your BC547 bipolar. My readings for similar relays were not even half that but since it's still not clear whether a ground spring in...
by Brandon92
Mon Dec 23, 2019 7:36 pm
Forum: Troubleshooting
Topic: Relay won't flip
Replies: 40
Views: 1204

Re: Relay won't flip

see my post above
RigolDS5_sortprobe_withoutDiode.png
RigolDS5_sortprobe_withoutDiode.png (84.94 KiB) Viewed 414 times
To the OP, sorry for the "off topic" information.
by Brandon92
Mon Dec 23, 2019 7:35 pm
Forum: Troubleshooting
Topic: Relay won't flip
Replies: 40
Views: 1204

Re: Relay won't flip

Okay, lets pull this to the test on the bench. My test setup is a function generator that drives a BC547 via a 1k resistor. The relay is a G5v-2 from omron and the flyback diode is an 1n4148. And the power supply is set to 12V. Channel 1 (yellow) is connected to the output of the function generator....
by Brandon92
Mon Dec 23, 2019 9:43 am
Forum: Troubleshooting
Topic: Relay won't flip
Replies: 40
Views: 1204

Re: Relay won't flip

I'm convinced that diode is a holdover from the days of point contact germanium transistors. IMO practices like this tend to propagate throughout the ages more from a sense of superstitious ritual than science or engineering. Depending on load inductance and circuit impedance I would be surprised t...
by Brandon92
Sun Dec 22, 2019 11:30 pm
Forum: Troubleshooting
Topic: Relay won't flip
Replies: 40
Views: 1204

Re: Relay won't flip

That diode, across the relay coil, can not be cut out. In this case it is a fly back diode that observes the energy of the relay coil when it is turned of. As you might know an inductor wants to "keep" the current flow. But if he can't the voltage across the coil will be flying high. For example I t...
by Brandon92
Sun Dec 22, 2019 9:59 pm
Forum: Automation, sensing and robotics
Topic: 0-10 V analog output
Replies: 6
Views: 493

Re: 0-10 V analog output

If If you apply for example 5V to the valve, is it then open for 50% or doesn't it work then? If I apply 5V it opens 50%. Okay, I don't know how much knowledge you have about electronics. But you could also make it with the PWM generator of the raspberry pi itself. If you add a low pass filter (res...
by Brandon92
Sat Dec 21, 2019 2:05 pm
Forum: Automation, sensing and robotics
Topic: 0-10 V analog output
Replies: 6
Views: 493

Re: 0-10 V analog output

If you apply for example 5V to the valve, is it then open for 50% or doesn't it work then?
by Brandon92
Sun Nov 03, 2019 10:05 am
Forum: Advanced users
Topic: Control power from LiPo to Pi via external MCU
Replies: 32
Views: 2275

Re: Control power from LiPo to Pi via external MCU

Could you post a picture of the setup. Maybe we see something wrong with it. And what is the type of battery that you are using. I see that a lot of measurement is done with turning the voltage down to see where the Rpi will stop working. But did someone the same test with turning the voltage up. To...
by Brandon92
Sat Oct 26, 2019 9:12 pm
Forum: Automation, sensing and robotics
Topic: Creating a Vehicle interface system
Replies: 2
Views: 998

Re: Creating a Vehicle interface system

Hello, This in the basic possible to do. However you are planning this to use in an automotive application. And I think also in a very "important" place. For example you have a bug in you program that diced to open an solenoid valve of your left front of your car. At that time you drive in a right c...
by Brandon92
Fri Jul 05, 2019 5:53 pm
Forum: Automation, sensing and robotics
Topic: Relee boars + RS485
Replies: 20
Views: 1366

Re: Relee boars + RS485

Thank you for your response and time! - a better board. could you give me a link with one that has 8 relays? - the wiring is planed by an electrician (not me), professional work (but i have to give him the boards) - each board of relays + board control is placed in every single room (+ relays conne...
by Brandon92
Mon Jul 01, 2019 5:47 pm
Forum: Automation, sensing and robotics
Topic: DS18B20: Influence of supply voltage on temperature
Replies: 21
Views: 2432

Re: DS18B20: Influence of supply voltage on temperature

If the parts are fake this could indeed be a problem. Maybe it is something like this: Your start up the DS18B20 at 5V The DS18B20 goes on, and set some (internal) registers correct according to the power supply voltage. (self calibration at start up?). And the DS18B20 assume that that voltage stays...
by Brandon92
Mon Jul 01, 2019 5:31 pm
Forum: Automation, sensing and robotics
Topic: Relee boars + RS485
Replies: 20
Views: 1366

Re: Relee boars + RS485

Okay, then I will tell you the following: Is that relay board according to the high voltage standaard (clearance and creepage distance, quality of the solder and PCB and ... Is the relay qualified to switch your load safely and reliable. So can the relay handle the inrush current of your load. Becau...
by Brandon92
Sat Jun 29, 2019 6:53 pm
Forum: Automation, sensing and robotics
Topic: Relee boars + RS485
Replies: 20
Views: 1366

Re: Relee boars + RS485

First of all. Before I'll give you any advice for this project.
What do you know about electronics, and is this your first project? And have you any experience in this field. Because this is not a easy project and you need probably a lot more than that (wrong) relay board.
by Brandon92
Sun Jun 16, 2019 6:15 pm
Forum: Off topic discussion
Topic: Arduino connection to the PI (with 12C)
Replies: 18
Views: 3805

Re: Arduino connection to the PI (with 12C)

Both voltages need to go to the level shifter, otherwise the level shifter will not work. Edit: The voltages are used to provide power to the level shifter itself. Without that connected it will not work properly. I could give you a detailed explanation why. Hi! Can you explain me pls? What do you ...
by Brandon92
Mon May 27, 2019 7:55 pm
Forum: Other projects
Topic: Using RPI as House Alarm controller
Replies: 2
Views: 416

Re: Using RPI as House Alarm controller

Why are you not solving this in software. For example this to get a idea (not real code):

Code: Select all

if hardware pin = high or software pin = high:
    Alarm = active
Else
    Alarm = deactivate
You could also write it in a way that one overrule the other.
by Brandon92
Fri May 24, 2019 3:40 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO input current draw
Replies: 12
Views: 1060

Re: GPIO input current draw

I am going to google how to make a filter with resistor+capacitor :geek: For future readers' reference, a simple low pass filter consists of a resistor between Vcc-in and Vcc-out, bein the Gnd common, a capacitor between the Vcc-out and Gnd. How to size said resistor and capacitor is out of my comp...

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