💬 MDMSNode "Lighting"

[rubenverhoef]

Is it possible to dim the light with this device? (and also LED lights)

[kalina]

@rubenverhoef Unfortunately, it isn't possible. I got the task to control the lighting on the basis of fluorescent and LED lamps, where dimming is not provided. But if it becomes necessary, in the new version MDMSNode "Lighting" I might add it.

[Koresh]

Nice project. I like high density placement :thumbsup:
But how this device will be cooled?
Bt137s dissipates a lot of power (see picture)

So it will dissipate 1W at 0.8A current. But Bt137s has 75K/W thermal resistance from junction to ambient (without heatsink).
This means a junction temperature will be ~100 celsius degrees if it lies on the table with connected less than 200W device. If we puts it inside a closed box... :fire: These is very rough estimation, but it pause for thought I think :)
PS
15mm height... You are cunning, at least 20mm :trollface:

[kalina]

@Koresh Thank you for your detailed question and interest in my project. I will try to explain.
Firstly, as I wrote earlier, I design the device to control the LED and fluorescent lamps. The max power, which I hope to use, not more than 35-40 watts. Following this, the current through the triac should not exceed 0.2-0.3 A. So, the power dissipated in the triac will not exceed 0.5W.

Secondly, I created the special area on the pcb (as you can see in the picture, the polygons on the top and bottom sides + vias),

which provides heat distribution and dissipation.
Thirdly, the fuse have to provides safety. Value of fuse, if somebody wants, can be set 0.2A. Also, close to the triac I put a thermistor.
As soon as I get the pcbs and soldered, I’m going to test it carefully and I’ll share with the results.
And as about the size, you are right, it will be, at least, 20 mm.

[kalina]

I have already received the pcbs. I am sharing a few photos. Please, pay attention to the edge connector for programming, it looks good and technologically)). In the near future, I am going to solder device and start it testing!

[kalina]

First device is assembled and is under testing now... But i haven't diceded yet, which type of radios i wanna to use...

[kalina]

Two variants of MDMSNode "Lighting"

[Cliff Karlsson]

@kalina
Can we buy it preassembled soon?

[kalina]

@Cliff-Karlsson Yes, i have made 10 pcs. But if necessary i can solder more. Price for model with RFM69 is 23$ and with NRF24L01 is 20$...

[Cliff Karlsson]

Ok, great. Are there any progress on the MDMSensor "Multisensor" and gateway?

[kalina]

@Cliff-Karlsson Yes, gateway is ready, but MDMSensor "Multisensor" is still in progress...

[tonnerre33]

Hello

Why do you use a triac instead a relay for command the light ? What is the point ?

[kalina]

Hi @tonnerre33. MOC3043 triac includes the function of Zero Voltage Crossing, this mean that triac can trigger only when AC voltage close to 0 V. SSR doesn't use this feature. If you use just one device with ordinary relay or SSR, it is not appreciably, but if the number of switching devices increases and they all switch on at the moment of maximum value AC voltage, this will produce a lot of impulse spikes of voltage, which is not desirable. Ordinary relay also makes a not comfortable sound...

[tonnerre33]

@kalina thx for your answer ;)

[kalina]

Hi, I want to share good news in the my project. Lighting has become more safer.
Instead the enclosure, I use a heat shrink tubing 3M MDT-A-32/7.5.

Here's result.

[jeremushka]

Your system works with phase and neutral wires? Will you make it compatible without neutral as well? In my house installation no neutral behind the wall switch only phase. And o the lamp side only neutral and the return wire from the wall switch.

[kalina]

@jeremushka said:

Your system works with phase and neutral wires?

Yes.

Will you make it compatible without neutral as well?

Actually, no. Why do you plan put this into the wall switch area? As for me, i am going to put "Lighting" near the lamp. Wall switch must be as a push button (normally closed). When you press button circuit opens (on short time) and Atmega328 resets and toggles lamp state. It means that "Lighting" always is conneted to the AC line. You can also change lamp state directly from your controller at any time. See picture below.

[tonnerre33]

I didn't know this method ;)

@kalina said:

When you press button circuit opens (on short time)

Do we have a limite time for circuit open ?

Atmega328 resets and toggles lamp

How do you do this in the sketch ?
Where can we find the sketch ?
What are the consequences for the components life ?

With this use, the reboot time will impact the response time bewtween the command and the lamp power , isn't it ?

[kalina]

@tonnerre33 said:

@kalina said:

When you press button circuit opens (on short time)

Do we have a limite time for circuit open ?

Yes, of course. In my opinion, this time we can determine in practice, i don't know how can it be calculated. I haven't done it yet, I will try to do it on weekend.

Atmega328 resets and toggles lamp

What are the consequences for the components life ?
With this use, the reboot time will impact the response time bewtween the command and the lamp power , isn't it ?

I have no answers on this questions, it is certainly disadvantages of this method, but i wont use wall switch very often, i prefer to operate via controller. No need reboot uC in this case.

[jeremushka]

@kalina : your solution is quite interesting when push button are installed. Yes, i would like to put the system in the wall switch. For the moment, i connect the switch of the house on the arduino. The system is powered by phase and neutral in the garage as behind the switch i had the neutral wire. However, in the house no neutral like on your picture. So, im checking about using leakage current which should be enough to power on the system.... Not sure.