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by tlfong01
Thu Jun 07, 2018 1:32 pm
Forum: Automation, sensing and robotics
Topic: Relay Module KY-019 5V
Replies: 488
Views: 81802

Re: Relay Module KY-019 5V

Hello, What is the most simple way to make Relay Module KY-019 5V work with GPIO? http://okystar.en.alibaba.com/product/1498514200-220205206/1_channel_Relay_Module_KY_019_5V_Relay_for_Arduino.html OkStar seems to have replaced KY-109 by OKY3011 https://okystar.en.alibaba.com/product/60525869932-805...
by tlfong01
Wed Jun 06, 2018 2:07 pm
Forum: Automation, sensing and robotics
Topic: Relay Module KY-019 5V
Replies: 488
Views: 81802

Re: Relay Module KY-019 5V

Make sure that the box is earthed ;) Ah yes, grounding or earthing the box is first and foremost. I made a short ground wire and screwed two ends OK. But I found two problems. 1. My aluminium box is anodized, meaning the surface is not a conductor, so the box is like a plastic box and there is no r...
by tlfong01
Wed Jun 06, 2018 7:23 am
Forum: Automation, sensing and robotics
Topic: Relay Module KY-019 5V
Replies: 488
Views: 81802

Re: Relay Module KY-019 5V

... 5V coil relays are quite current-hungry (similar relays need similar power to switch them, so a coil designed for 5V needs 2.4 times the amount of current a 12V coil would need), so a I would prefer to use 12V coil relays if possible (if there is a 12V supply available). Yes, I checked the rela...
by tlfong01
Wed Jun 06, 2018 7:03 am
Forum: Automation, sensing and robotics
Topic: Relay Module KY-019 5V
Replies: 488
Views: 81802

Re: Relay Module KY-019 5V

Use the relay on your RPi to switch 24V. Run that in a long cable to where you want to switch the mains load. Have the mains relay in a safe box away from danger. Thanks for your suggestion. Actually I googled a similar idea a week ago, as summarized below. ... The fan may be a much more difficult ...
by tlfong01
Wed Jun 06, 2018 3:48 am
Forum: Automation, sensing and robotics
Topic: Relay Module KY-019 5V
Replies: 488
Views: 81802

Re: Relay Module KY-019 5V

Apart from that isolation these type of boards usually have bare contacts, and tracks on the switch contacts very close to other tracks on the board so be very careful!! Many thanks for your advice. I was not aware of the bare contacts. I looked closely at the PCB and found that the relay connector...
by tlfong01
Tue Jun 05, 2018 2:46 pm
Forum: Automation, sensing and robotics
Topic: Relay Module KY-019 5V
Replies: 488
Views: 81802

Re: Relay Module KY-019 5V

A word of caution with relays used to switch mains power. If they don't include opto-coupling insulation (and maybe even if they say they do) I would strongly suggest that they should be controlled through an opto-coupler and not directly a GPIO or transistor. Thanks a lot for your advice. I used t...
by tlfong01
Tue Jun 05, 2018 2:07 pm
Forum: Automation, sensing and robotics
Topic: Relay Module KY-019 5V
Replies: 488
Views: 81802

Re: Relay Module KY-019 5V

That schematic is poor. For one thing: if the transistor were fitted the way it is shown, the circuit wouldn't work. (with the transistor the right way around). ... The schematic is indeed weird, and the transistor should be inverted. I have redrawn the schematic as attached below. References About...
by tlfong01
Tue Jun 05, 2018 7:14 am
Forum: Automation, sensing and robotics
Topic: Relay Module KY-019 5V
Replies: 488
Views: 81802

Re: Relay Module KY-019 5V

Looking at the specs, it does clearly state '3.5 V-12V to TTL control signal'. Expecting it to switch reliably at 3.3V is expecting it to reliably work out of spec if I'm interpreting the data correctly. It's often difficult to interpret specs when they're not written in correct English. I was not ...
by tlfong01
Tue Jun 05, 2018 2:58 am
Forum: Automation, sensing and robotics
Topic: Relay Module KY-019 5V
Replies: 488
Views: 81802

Re: Relay Module KY-019 5V

Richard-TX wrote:
Thu May 15, 2014 1:48 pm
without a schematic, it is impossible to say what the issue is.
So I found the schematic, though 4 years too late!

http://tinkbox.ph/sites/tinkbox.ph/file ... KY-019.pdf
by tlfong01
Sun Jun 03, 2018 8:58 am
Forum: Automation, sensing and robotics
Topic: Relay Module KY-019 5V
Replies: 488
Views: 81802

Re: Relay Module KY-019 5V

. . . the specs, it does clearly state '3.5 V-12V to TTL control signal'. ... It's often difficult to interpret specs when they're not written in correct English. . . . Actually there are several variations within that same designation. 1. 5V relay 2. can be use for MCU 3. TTL control signal is 5V-...
by tlfong01
Sun Jun 03, 2018 6:44 am
Forum: Automation, sensing and robotics
Topic: Relay Module KY-019 5V
Replies: 488
Views: 81802

Re: Relay Module KY-019 5V

The 3V3 rail is not limited to 50mA. That is for GPIO and the 3V3 rail is not GPIO. The spec is not published that I have found. The RPi3B has a 1A regulator so the current available = (1A - whatever the RPi uses). I am guessing 2 or 300mA or more. When the RPi is powered via the micro USB port the...
by tlfong01
Sat Jun 02, 2018 2:10 pm
Forum: Automation, sensing and robotics
Topic: Relay Module KY-019 5V
Replies: 488
Views: 81802

Re: Relay Module KY-019 5V

5V Relay KY019 Specification I bought a KY019 relay module some weeks ago. I could not find the specification ( Errata - the shop does provide a spec, but placed below some irrelevant promotion ads, so I missed it ) so I used an adjustable voltage regulator as input signal, and two multi-meters to ...

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