German Meter WS74 (WS7412.1) works with Infrared LED - Will it also work?

[SmartLiving-Rocks]

Fantastic job! That is really great, what you have created!

Now I also need to monitor my energy usage. So I have checked my meter for an LED, but it was not visible (at least for the human eye). So I've had a look at the manual and it says it is an infrared LED (5000 Imp/kWh). I am wondering if the photodiode will also work, or do I need a different one?

I have attached a photo of my meter as well as a screenshot of the manual. Here you can find the full manual in German

Thanks in advance and have a nice day!

[OttoWinter]

Hi, I don't think the photodiode module listed in the README would work here (but I also didn't find any datasheet for it)

Generally the LED will probably be emitting in the range of 800-1000 nm (commonly used in TV remotes and such)

But you can instead look for phototransistors like this one: https://m.banggood.com/PT908-7C-Side-phototransistor-1_5mm-Transparent-860nm-400-1100nm-Photosensitive-Receiver-p-1752121.html?rmmds=search&act_poa=SKUG13853&cur_warehouse=CN - the important bit is that the datasheet wavelength contains the LED wavelength.

You can validate it's likely in the 800-100 nm range by pointing your smartphone camera at the LED - if you see it blink then it's good.

[klaasnicolaas]

I think the Glow works fine on this meter, however you have a different impulse rate so the multiply for power in filter will be different. In your case: 12.

[SmartLiving-Rocks]

Thanks for your answer. Regarding my own research, I think my meter has an extended data interface - eHZ: elektronische Haushaltszähler

You can read it out with a IR-read/write head. It has two main optical components:

1. sfh487-2
2. sfh309fa-4

Please see here a detailed technical description of the reader as well as a How-to Video

There is also a version for ESPeasy but I definitely prefer ESPhome! Is that possible and how much work is it @OttoWinter ?

But to keep it simple in the first step, I would like to try out (and support your work) your solution @klaasnicolaas ? I think Paulus mentioned that there is a shop, and we can buy it for around 20$. Where do I find it?

Thanks in advance you two and have a nice Sunday!

[klaasnicolaas]

Number 5 is indeed a separate interface that is also used by people from your energy company to configure your meter etc. But the Glow will work fine on number 8 just adjust the multiply values for your 5000 imp/kWh rate.

I don't sell the Glow in a webshop. The one that Paulus has often mentioned is Marcel Zuidwijk's P1 smart reader, which you plug into the serial port of your meter. But for those who really want to support/appreciate me in a financial form, it has recently become possible to sponsor me via Github Sponsors.

[fourtrax01]

I can confirm that it does work with the ir led on my sensus meter after adjusting the potentiometer on the photodiode. I don't know my pulse rate on my meter yet so still have to figure that out.

[klaasnicolaas]

@fourtrax01 IR LED? I think you mean just a normal LED. The rate should be listed somewhere, if you need help open a separate issue with information / photo of your meter and we will look for it.

[mcguenther]

I can also confirm that a regular photodiode works with the WS74. I bought a board with the LM393-N on ebay which specifies the range of the photodiode as 400 to 640 nm. Although I cannot see the pulse with my bare eye, my set-up has worked ok for a day now.

[yan14]

Number 5 is indeed a separate interface that is also used by people from your energy company to configure your meter etc. But the Glow will work fine on number 8 just adjust the multiply values for your 5000 imp/kWh rate.

I don't sell the Glow in a webshop. The one that Paulus has often mentioned is Marcel Zuidwijk's P1 smart reader, which you plug into the serial port of your meter. But for those who really want to support/appreciate me in a financial form, it has recently become possible to sponsor me via Github Sponsors.

if i get the math right the multiply must be changed from 0.06 to 0.12 and for the total from 0.001 to 0.002, right?

[yan14]

Thanks for your answer. Regarding my own research, I think my meter has an extended data interface - eHZ: elektronische Haushaltszähler

You can read it out with a IR-read/write head. It has two main optical components:

1. [sfh487-2 ](https://www.mouser.de/ProductDetail/OSRAM-Opto-Semiconductors/SFH-487-2?qs=nTDll3UaDK6ZS6zeY7T0tw%3D%3D)

2. [sfh309fa-4](https://www.mouser.de/ProductDetail/OSRAM-Opto-Semiconductors/SFH-309-FA-4?qs=nTDll3UaDK5PTBKWZyYpiQ%3D%3D)

Please see here a detailed technical description of the reader as well as a How-to Video

There is also a version for ESPeasy but I definitely prefer ESPhome! Is that possible and how much work is it @OttoWinter ?

But to keep it simple in the first step, I would like to try out (and support your work) your solution @klaasnicolaas ? I think Paulus mentioned that there is a shop, and we can buy it for around 20$. Where do I find it?

Thanks in advance you two and have a nice Sunday!

The interface 5 uses SML. ESPHome has no libary for this. See this feature request:
esphome/feature-requests#1041

[klaasnicolaas]

if i get the math right the multiply must be changed from 0.06 to 0.12 and for the total from 0.001 to 0.002, right?

@yan14 If you use the latest version you don't even have to calculate anymore, just enter the imp/kWh rate value at the top 😉

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