19
votes
Are relays reliable for long time use?
This is an old post but I am a controls engineer who programs industrial machines so I have 2 cents. I have a machine that does 20,000 cycles a day and I must use solid state relays even if they will ...
- 201
8
votes
Accepted
What does the circuit look like to switch two lights using two switches into four different states?
Rewriting your truth table a little more succinctly:
...
- 171k
8
votes
What does the circuit look like to switch two lights using two switches into four different states?
Possible connection scheme (you have given partial information so this may not be correct)- SWA and SWB are '3-way' (by North American definition) switches
simulate this circuit – Schematic ...
- 384k
7
votes
Accepted
Programming Intel i3 like RPi
Of course it's possible to build and run an i3-based computer with no OS. How do you think the OS starts up in the first place? But it's a very deep and complicated stack.
I assume that what you have ...
- 1,237
7
votes
Accepted
How to automatically turn off a Fan after a fixed amount of time?
Replace the existing switch with a UL-rated timer switch. Anything else will run the risk of invalidating your fire insurance.
- 171k
7
votes
Accepted
How to dynamically simulate an EV plug disconnection in order to automate charging power setup
UPDATE: Your requirement is already solved by the Wallbox Pulsar Plus or Myenergi Zappi, both of which can put CT clamp meters on your service wires and redirect solar surplus to the car, dynamically ...
5
votes
Accepted
How to control a device that need to be updated over internet?
There are high chances you don't need to reflash remotely. Just write a generic control algorithm supporting all target sensors and actuators, and let the user download configuration parameters which ...
- 25.7k
5
votes
Accepted
Can I use a standard latching relay to switch AC for a power socket?
The relay
The datasheet clearly says, in the "Contacts" chapter:
Rated load: 16 A at 250 VAC
Rated carry current: 16 A
Max. switching current: 16 A
And there is no mention of a max switching ...
- 16k
4
votes
direct ZigBee communication with Philips Hue smart light bulbs
No you can not. The Hue network is a ZigBee Light Link network, and a ZigBee Light Link Network uses "secret" ZLL security keys. Home Automation networks use public security keys, and hence if this ...
- 446
4
votes
ESP32 is safe enough to control a door lock
Commercially available residential and commercial locks use off-the-shelf, readily available microcontrollers, and the wireless locks again, use off the shelf modules/radios. There is nothing special ...
- 13.8k
4
votes
How to modify a 433.92 MHz signal to a 434 MHz signal?
"How can I modify a 433.92 MHz signal to a 434 MHz signal?"
Don't. Frequency-wise, what you bought is fine.
The difference is only 0.02%, the electronics would have a very hard time to distinguish ...
- 48.5k
3
votes
Accepted
Jumper Setting Modes in PIR motion sensor
If you move the jumper to L position the sensor will 'toggle' (change state) every time motion is detected - probably providing the on-board timer has timed out. This is unlikely to be of much use in ...
- 171k
3
votes
Accepted
Is amperage constant or relative to the device?
You should immediately disconnect this and be thankful nobody got electrocuted and your liability insurance company didn't find out about your wiring.
The current that light draws is small enough ...
- 312k
3
votes
Accepted
Two-phase system for a smart house?
'2-phase' just means a split 240V feed with a neutral. These feeds are normally called out as L1, L2 and of course N for neutral. Neutral is tied to earth ground at the panel, L1 and L2 are 120V with ...
- 51.2k
3
votes
Accepted
12V-only (and no 110V/220V) household electrical installation
There's more to consider than the voltage level needed by the devices typically connected to an outlet.
Having a wall outlet implies that the devices to be plugged into aren't predetermined. E.g. you ...
- 3,876
3
votes
Accepted
Can I connect ten RS485 modbus kWh meters to one RJ45 modbus server?
There are many ways to organise this, and the following is just one which is intended to be as easy as possible to do.
Yes, Modbus-RTU is a bus. Each node is an RS-485 half-duplex device with three ...
- 13.2k
2
votes
How can I control a 120v, 1amp fan with a Nest thermostat?
Ecnerwal had it right, just providing a little more clarity and created my own diagram. I live in a condo building where each unit has a blower unit that blows across water filled coils to heat/cool (...
- 21
2
votes
Splitting mains power into multiple relay-switched circuits
Option the first would be skip this if you are truly unfamiliar with mains power - it's not something you should attempt without having a very good idea what you are doing and how to do it right, ...
- 5,604
2
votes
Atmel AVR - Integrated programmer onboard
You don't want to waste all those extra components, I'd think.
First of all, you can do what Malphas suggests: Add your in circuit programming header (most likely JTAG in this case) to your design ...
- 18.3k
2
votes
Splitting mains power into multiple relay-switched circuits
I suggest you find a decent quality plugboard / socket strip and mount everything inside that. You'd need to find one that's openable. Many are using a threaded 'nail' fastener now and they are not ...
- 171k
2
votes
Accepted
Reversing a small synchronous gearmotor
As far as I can make out that's the same type of motor used in a microwave oven for turntable drive. On startup they run alternate directions. The direction is not controllable. The fact that it's an ...
- 171k
2
votes
Accepted
Home Automation
As was mentioned above, PIR would be the way to go. It consumes VERY little power and, as was mentioned detects change rather than static IR density. This method, I believe uses a device called a ...
- 755
2
votes
Accepted
Home-automation standard for custom devices
So is there a standard for house automation related to a particular protocol or not, where devices can be controlled by a compliant software and where devices can communicate their capabilities ?
No. ...
- 171k
2
votes
Home automation: Adding relays in series vs parallel
You have identified some of the problems with this type of project. Andy has shown how a two-way switch circuit is wired but that will involve extensive rewiring of the house.
I caution anyone ...
- 171k
2
votes
how can i build a cheap linear actuator
You can procure a linear servo as used in RC gadgets. Then you just need to feed it a pulse train in the usual format.
- 384k
2
votes
Thermometer type in electrical water heater
I believe that @TurboJ is correct that there is no galvanic isolation. That would make the signals very difficult to deal with safely- the sensor appears to be tied to one side of the mains.
As it's ...
- 384k
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