Reading a smart meter using infrared

[charliecoutas]

I had a chat with ChatGPT and she told me that I could read my smart meter legally using infra red. There is a port on the front of the meter that does IR RS232 at 9600. A bit of research came up with a Vishay document that shows how to do it. Part of it says this:

"For pulse shaping and recovery, an encoder / decoder device, such as Texas Instruments TIR1000, is recommended. The front end including transmitter and receiver should be realized for example by the integrated transceiver module TFDU4101 or any other Vishay transceiver model."

That sounds a bit complicated, has anybody here done anything similar? I remember that one forum member was working on smart meters. It would be handy to receive real-time readings. I'm still trying to find the elusive  200+ watts that is burning away 24 hours a day.

Charlie

[CPR]

I'm still trying to find the elusive  200+ watts that is burning away 24 hours a day.

How ironic it would be if it were the smart meter... ?

[RGV250]

Hi,
Does it tell you the format, I have an Eco-eye and without knowing the format I wouldn't have had a clue.

Bob

[charliecoutas]

Indeed, ironic or what? No, I've eliminated that possibility.

Yes Bob, sort of, ChatGPT said lots including getting comms activated She said:

Step 1 — Wake-up request

Send: /?!\r\n

Step 2 — Meter responds:
/LGZ5E470\r\n

I think we could do it, ask ChatGPT for "IR comms format with a smart meter", you'll get lots of good stuff.

It's just the IR half duplex link that looks tricky. I'm also pretty sure that it's not the 35/6/7Khz stuff that we are used to.


Charlie

[charliecoutas]

Just to tie up a loose end: I found the constant 200+ watt drain on my mains. We have a half/fridge half/freezer which must be over 30 years old. I discounted this because fridges cycle on and off over a few hours and the 200+ was constant. Turning it off altogether hit the jackpot. Interestingly, it draws about 1800 watts for about ten seconds when switched back on. I assume this might be the motor capacitor start system not working. Anyway, it's going where all old fridges go just after Christmas.

Happy Christmas to Les, his good wife and all our members.

Charlie

[Stephen Moss]

It would be handy to receive real-time readings. I'm still trying to find the elusive  200+ watts that is burning away 24 hours a day.

I just had a look at the Now reading on the Smart Meter display in my Kitchen and from a purely visual indication it apears to update about every 10 seconds (maybe 30 seconds to settle after a big change, probably soem averaging going on), so even if I could read directly from the meter in the way you are investigating I they may not be updated any quicker than that, so generaly it may not be worth the effort.

Just to tie up a loose end: I found the constant 200+ watt drain on my mains.

The following is a bit redundant now, but for refernce in case anyone has a similar problem in the future...
My 'Now' display reading was varing over the last 30 minutes between 44W and 230W, so perhaps for it to spike to 200+ is not unusual, maybe video your display for an hour and watch it back in fast forward to see if it is contantly 200+ or not.
My Smart meter dispaly is currently reading in the mid 50's (PC & Monitor On, DVD & Soundbar on standby + Clock Radio & Fridge Freezer), but that jumps up by 80-100W while the Fridge Freezer is actively cooling. All my equipement is around 10 years old and I has good energy ratings, but it gives some guide values.
 
Still could be worse, when my smart meter display had a mad day...

[charliecoutas]

So when you bought your house, nobody thought to mention the steel rolling mill next door, wired to your smart meter? That would explain the 10.8MW!

Yes, my In Home Display updates every 8-10 seconds and I'm pretty sure that's the actual power at that instant. The meter obviously works out the actual consumption but it's a good guide. I want to get hold of that data so I can study things in more detail. It's not legal (according to ChatGPT) to tap into the RF protocol between the meter and the display, but it's ok to read the IR port. I think you can read that more often than every 10 seconds.

I hoping somebody here had done it. But if not then I'll give it a go. As far as I know you need a the clock that times the UART (in say, a PIC) and that is my main problem. It looks doable apart from that. So another question is: Can I get hold of the UART x16 clock outside the PIC? I don't want to use an external UART.

Charlie

[TimB]

Charles

Personally I would not bother with trying to read the meter. Get a clamp on unit Look for something like a "Tuya Smart WiFi Energy Clamp"

There are other makes and systems, way easier than rolling your own.

Tim

[charliecoutas]

What a good idea!  That is no problem, I've used current clamps a lot when I worked at Telonic. Tim, I owe you.

Have a good Christmas.
Charles

[RGV250]

Hi Charlie,
I use eco-eye, they do not sell the kits  now but I  use the transmitted to monitor different floors.
From memory it is 9600,8,N,1 and is 12 hex values IN mA

Bob

[John Lawton]

Unless the sensor uses true RMS measurement it's pretty worthless if you've got any switching power supplies on your power circuit, and who hasn't?

John

[charliecoutas]

Ah, that's a good point. Thinking cap on......