Cat Home DIY Q&A - Solenoid How To

[tlfong01]

NE555 controls KY019, which in turn blinks LED

NE555 controls KY019, which in turn blinks LED
(youtube) https://youtu.be/pbH05JnAHJg
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[Will5455]

I'm sorry can you please stop using colors in your text? It makes me dizzy.

[tlfong01]

I'm sorry can you please stop using colors in your text? It makes me dizzy.

Text Colouring

Thank you for your suggestion. My apologies for making you dizzy.

Let me tell you my text colouring story. It is a long story. So I am numbering the paragraphs.

1. I only learnt the alphabets A, B, C when I was 7. (At that time I already knew more than 200 Chinese characters and enjoyed reading children books.) I found it difficult to remember the weird snake like shapes and sequence (perhaps my short memory is much shorter than average, or my little head already got squeezed in too much Chinese stuff), so I could only 'count' to K.

Then a traumatic thing happened. My parents wanted me to leave my literacy school and transfer to a school to learn some English so that when I finished primary school I could started working and make a better living because I knew English. (At that time I already worked as a part time plastic toys sweat factory supervisor, overseeing naughty kids one or two years smaller than me.)

Anyway, back to my scary experience. I still vividly remember my feet and hands started trembling when sitting in the primary 3 written entrance exam, and read the question to write down the 26 English alphabets in both big and small shape (A, B, C, ... a, b, c, ... etc)

I only knew how to write about 10 big alphabets. I tried hard to write A, B, C, to J and then no go. I sadly thought I should have no chance getting into the high class school which is not meant for grassroot kids like me, ...

Hong Kong Toy Industry - Celebrating 60 Years of Success
https://www.industryhk.org/upload/media ... f039a9.pdf

/ to continue, ...

[tlfong01]

Back EMF Flyback Diode Selection Notes

So far I have fried two power supplies - one LM2956 based 12VDC to 5VDC 2A, the other 220VAC to 12VDC 1A. I think I need to get more serious and look at the prevention measures. The first thing I need to look at is what kind of flyback diodes I should use for the solenoid.

1N5822 Schottky Barrier Plastic Rectifier
https://www.vishay.com/docs/88526/1n5820.pdf

Features
* Guardring for overvoltage protection
* Very small conduction losses
* Extremely fast switching
* Low forward voltage drop
* High forward surge capability
* High frequency operation

Applications
For use in low voltage high frequency inverters, freewheeling, DC/DC converters, and polarity protection applications.

1N5819 1A Sschottky Barrier Rectifier
https://www.diodes.com/assets/Datasheets/ds23001.pdf

Features
* Guard Ring Die Construction for Transient Protection
* Low Power Loss, High Efficiency
* High Surge Capability
* High Current Capability and Low Forward Voltage Drop
* For Use in Low Voltage, High Frequency Inverters, Free Wheeling, and Polarity Protection Application

FairChild/On 1N4001-1n4004
https://www.mouser.hk/datasheet/2/308/1 ... 118319.pdf

Features
* Low forward voltage drop
* High surge current capability

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[tlfong01]

Back EMF Flyback Diode Selection Notes
1N5822 Schottky Barrier Plastic Rectifier
https://www.vishay.com/docs/88526/1n5820.pdf
1N5819 1A Sschottky Barrier Rectifier
https://www.diodes.com/assets/Datasheets/ds23001.pdf
FairChild/On 1N4001-1n4004
https://www.mouser.hk/datasheet/2/308/1 ... 118319.pdf

1N5819 Schottky Diode to Flyback EMF

Now I have used 1N5819 to do the freewheeling. I also have used a 250V 5A fast blow fuse, just in case, ...

I always thought that Schottky diode was invented by the American guy William Schottky who coinvented the diode in Bell Lab. But actually Schottky Diode was invented by a German guy also called W Schottky. How confusing. (I am hearing the German guy LOL!)

Schottky diode - Wikipedia
https://en.wikipedia.org/wiki/Schottky_diode

Walter H. Schottky - Wikipedia
https://en.wikipedia.org/wiki/Walter_H._Schottky
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[tlfong01]

KY019 + ZYE1 Assembly and Testing Notes

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[tlfong01]

Testing ZYE1 20N Solenoid

I tested the ZYE1 20N and found that the KY019 relay can drive the solenoid at 0.5Hz without any problem.

However, I found the holding current is an enormous 4.5A! This means that the solenoid can not hold too long, because at such a big current, both the PSU and the solenoid would heat up and break down sooner or later.

The big guy eating 4.5A is too dangerous. I need to check out smaller solenoids now.
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[tlfong01]

Testing ZYE1 20N Solenoid
The big guy eating 4.5A is too dangerous. I need to check out smaller solenoids now.

Big Solenoid Test Results Summary

20N = 4.5A
8N = 1.5A
4N = 770mA
0.8N = 350mA

I guess I would first try the 4N guy to see if it can pull the hinged cat food container window.

Before that, I also need to check the solenoid valves for my rooftop garden plant water thing.

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[tlfong01]

Before that, I also need to check the solenoid valves for my rooftop garden plant water thing.[/color]

Cat Home DIY Question 21 - How to use solenoid valve

Introduction

I started playing with relays about six months ago. I joined in the Raspberry Pi Forum on the topic KY019 Relay [1] . The thread of postings has become so very long, that many of the interesting posts are deeply buried here and there, have become orphans and too hard to find by sequentially reading the posts.

I think there are many ways to solve the orphan posts problem. One way is to make the topic specific and keep the thread short by not including off topic posts.

One of the 101 items in my 2019 New Year Resolutions List is to learn how to properly set up a GitHub repository. I read the newbie guide and found one interesting thing I never thought before - ie "forking". Forking lets me start a new project base on an old project. This is particularly useful for me, because almost all my Micky Mouse hobbyists projects mentioned in the Rpi forum end up a failure. And I am not ashamed embrassaed at all, because (1) I am learning by mistakes, (2) I am doing problem based learning, where solving a problem is not the aim, but the tool to learning, ...

Anyway, I am thinking of starting a new project, or a new topic based on my old topic. The old topic is solenoid, the new topic is solenoid valve.

/ to continue, ...

Fork a repo - GitHub Help
https://help.github.com/articles/fork-a-repo/

A fork is a copy of a repository. Forking a repository allows you to freely experiment with changes without affecting the original project.

Most commonly, forks are used to either propose changes to someone else's project or to use someone else's project as a starting point for your own idea.

Cat Home DIY Question 001 - How to use relay (KY019)
Cat Home DIY Question 011 - How to use solenoid (ZYE1)
Cat Home DIY Question 012 - How to use solenoid valve (?)
Cat Home DIY Question 021 - How to use weight sensor (HX711)
Cat Home DIY Question 031 - How to use WiFi microchip (ESP8266)

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[Earlton2]

its likely of no significance in this circuit but the led diode in the transistor base will slow down the base discharge and delay the turn off. i.e. placing the transistor in linear mode. if anything i would suggest adding a 4k7 to gnd at the base.

[tlfong01]

its likely of no significance in this circuit but the led diode in the transistor base will slow down the base discharge and delay the turn off. i.e. placing the transistor in linear mode. if anything i would suggest adding a 4k7 to gnd at the base.

KY019 Relay Module NPN BJT S8050 Biasing Circuit Analysis

Ah, do you mean the status LED of the KY019 Relay Module, in the following post?

https://www.raspberrypi.org/forums/view ... 5#p1417740

Actually, the status LED is built into the KY019 module. I agree removing the LED will turn on the NPN BJT a little bit faster, but not significant at all (Note 1 to add later). I also agree adding 4k7 from base to ground will also switch off the BJT a little bit faster (to pass CB leakage current to ground), but again not significant at all.

Moreover, the maximum usable, reliable relay operating frequency is less than 10Hz. So making switching on/off faster is useless, just wasting your circuit design time.

I don't agree that the NPN BJT S8050 with high beta won't saturate. I did do the Ic/Ib calculation then. Perhaps you can show me your calculation.

Appendix - KY019 References
https://www.raspberrypi.org/forums/view ... 8#p1323061