New improved P1 ethernet reader: v3.1

Straight after releasing v3.0, I knew there was room for some improvement. Not that v3.0 was bad. Yet there where some things that needed to be addressed…

UCB C “bug” 🐞

Yeah I know, I was complaining about the USB-C from the Raspberry Pi wasn’t fully compatible. The more advanced power adapters weren’t working on the Raspberry Pi, and neither on my P1 ethernet reader. I was fine with that, knowing nobody would use an powerful and expensive power supply to power it (in case of older meters). And the “simple” cheap USB-C adapters where all working fine. So why bother?

Well it kept bugging me (literally). So I read some documents about the standards and soon found that the easiest solution was to place two resistors of 5.1k, one to each cc pin and to ground.

Power converter 5v > 3v3 🔋

Since the beginning I was using the LM1117 3.3v LDO (low drop out) regulators. Why? I knew they where good! They’re also quite beefy, as well as price, as capability. They can handle up to 1 amp and cost me about a euro a piece. Sure I could find them cheaper on AliExpress, yet some components I want to choose for better quality and came from Farnell. I know, most would say that they’re all the same. A voice in my head told me to go for that.

Yet why go for 1 amp versions, if you only need 250mA max? (that’s what the P1 port from DSMR 5.x can provide). So I found these smaller and cheaper ones. The ME6211C33M5G-N. The are rated for 200mA normal use and 600mA max. These should do perfectly. Also they’re small, it has the same package as the inverter I use: SOT-23-5.

I’ve sworn never to use gif’s on my website… sorry for this one 😉

The result: v3.1

Well, it is exact the same as v3.0. The only difference is what’s between the pcb’s. Here you can see the regulator and inverter next to each other (LDO1 and U2):


  1. Rick

    Plannen of ideeen om deze uit te breiden met poe (power over ethernet) ondersteuning. Voor alle mensen zonder dsmr5

        1. Marcel

          Die ken ik, is niet heel moeilijk om aan de praat te krijgen. Maar dat kost €25 en dan nog verzendkosten. Komt het van buiten EU dan ook nog extra btw. Dan nog de extra kosten voor extra printplaatje en wat componenten. Je gaat al gauw maar de €40+

  2. Jacques

    Als uw “P1 Ethernet- reader” rechtstreeks verbonden is met mijn thuis-netwerk, kan ik dan toegang krijgen tot mijn slimme meter-informatie via een Windows- of Android-applicatie ?
    Bent u er zeker van dat uw apparaat in Belgïe ook functionneert ?

    1. Marcel

      Hey Jacques, mijn modules “spugen” de data vanuit de P1 poort het netwerk op. Je hebt nog iets nodig om te loggen. Dat kan dsmr-reader zijn, maar ook Home Assistant of Domoticz. Elk device in je netwerk kan de data ontvangen 🙂

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