Seeed

Other Hardware Home Automation
1

Dear all,
this is to post my experience on the following configuration:

I bought ufficial products on the relative websites.

I found two different types of problems.

PROBLEM #1 - Seeed Relay Shield
Having a look to the page of Seeed Relay Shield rev 1.0, they claim the digital pins that actuate the 4 relays are 7, 6, 5 and 4. When I tried the example sketch, relay 1 and 2 where not working. At the beginning I was desperate, thinking that the relays where broken. I did a try activating the digital pins 5, 4, 3 and 2 and... It worked!

In conclusion the board works, but what it is strange is that nobody noticed that pins 7, 6, 5 and 4 where not the correct ones. The correct ones are 5, 4, 3 and 2.

PROBLEM #2 - Relays
I fed the Arduino UNO + Seeed Relay Shield using the Arduino UNO Jack through the 12V provided by the power system. I also connected the 4 Finder relays coils with the common (-V) pin of the power system. To make a test I connected the 12V (+V) pin of the power system to the COM1 pin of the Seeed Relay Shield and the NO1 pin of the Seeed Relay Shield to the first Finder relay coil. I my objective was to drive the high voltage (220V - 10A) Finder relays using the Seeed Relay Shield, so that I can safely turn on/off some light electrics loads (mainly lights).

I know that the Finder coils are supposed to work with 12V AC and not 12V DC, but the shop seller showed me that the Finder Relays could switch also when fed with 12V DC.

I pilot the Arduino UNO via the USB cable and with a simple sketch, I can send commands to the of Seeed Relay Shield using the serial communication.

The problem occurs when I pilot the Seeed Relay that drives the Finder Relay to turn-on first and then to turn-off. When I turn-off the Seeed Relay. The Arduino UNO board indeed disconnect from the serial and stop receving commands. To make all the things work properly I need to disconnect and reconnect the USB cable.

If I drive, through the serial communication, the other Seeed Relays, everything goes as supposed. I disconnected the Finder Relay from the power unit and did the test again. In this case I can drive normally all the Seeed Relays. Find below a link to an image describing exctly this scenario (Finder Relay #1 disconnected): Link to the image

In brief it seems to me that these Seeed Relays somehow interfere back with the Arduino UNO operations. The other possibility is that the Finder coils, when deactivated, disturb the Arduino UNO power signal.

Is it possible? Is there anyone who as tried to do the same thing?

Any suggestion is nore than welcome!

Best regards,
Vincenzo Suraci

IMAG0697.jpg
IMAG0697.jpg2592×1552 939 KB

2

I add another important information, that somehow conduct me to a obvious response to problem #2.

I tried to power the Arduino UNO with a distinct power unit. In this case everthing works perfectly. So the morale is that powering the Finder Relay's coil and the Arduino UNO with the same 12V is not a good thing.

Further consideration. Since the Seeed's relays are low voltage (max 35V DC...) they are not suitable to pilot 220V AC loads. This leads to use external relays and an additional power unit to feed power up the relays' coils... Defenitevely they are not a good news.

I'll look for a different and chaper configuration.

VS