Pow-P1
¶ Technical specification
| Compatibility | P1 companion interface |
| Power meter interface | RJ12 |
| Maximum cable length | 5 m |
| Connection | Wi-Fi 2.4GHz b/g/n |
| Power | Powered from the meter |
| Weight (incl enclosure) | 40 g |
| Size | 70 x 39 x 24 mm |
| Input voltage | 5V |
| Operating power | 0,4 W |
| Data encryption | Supported |
| MQTT | Internal and external, including SSL |
| Home Assistant auto discovery | Yes |
| Protection class | IP20 (suitable for use in dry conditions) |
| Temperature range | -20°C to +70°C |
| Humidity | Non-condensing |
¶ Overview
Pow-P1 Connectors and buttons
Indicator LED
¶ Buttons
There are two buttons:
- Pressing the RES / R button restarts the microcontroller. Restart is indicated by a blink sequence on the LED.
- Holding the AP / A button down for 5-10 seconds sets the device in Access point (AP) mode. Do this if you need to reconfigure the Wi-Fi setting.
AP mode is indicated by steady yellow light on the LED (on older firmware: short yellow blinks).
¶ Indicator LEDs
The multicolour LED gives the following indications:
- Steady yellow light when device is in Access point (AP) mode
- Rapid green/red/yellow blink sequence when restarting
- Blue blinking while data arrives from the power meter
- Short green blink immediately after blue blinking: Data is recognized as valid.
- Red blink codes indicates errors. See Firmware User Manual.
- Steady blue light when the device is powered but not connected to the power meter.
If the blinking from the LED is disturbing during use, it can on newer hardware be deactivated in the settings:
¶ Mounting
Pow-P1 is supplied with a hook-and-loop fastener in two self-adhesive halves: one is attached to the device, the other to the mounting point. This lets you mount the device on the front of the meter, and remove it again without tools.
The standard cable is 30 cm, intended for exactly that. This works well in the great majority of installations.
If the Wi-Fi signal at the meter is weak, the device can be moved outside the fuse cabinet, where reception is usually better. The 30 cm cable is not long enough for this, and we do not sell a longer one — you have to source it yourself. Use a standard straight-through RJ12 cable, wired pin 1 to pin 1, pin 2 to pin 2 and so on — the same type as the one supplied.
Two limits apply:
- The Pow-P1 reads an open collector output from the meter at 115 200 baud, and at that data rate the cable cannot exceed 5 metres; a longer one will not work reliably, regardless of cable quality. And wherever you place the device, do not attach it to the cabinet door.
- The door is steel, and a metal surface directly behind the device acts as a ground plane for the PCB antenna inside. This both detunes the antenna and shields it in the direction of the door. The loss can exceed 10 dB — enough to turn a working link into one that drops out intermittently.
Mount it on the wall next to the cabinet instead, far enough to the side that it is not right up against the steel frame. A hand's width is enough. If you have no alternative to the door itself, let the device hang a few centimetres clear of the steel rather than resting against it.
You can verify the result on the Status/Info page, which shows the current Wi-Fi signal strength in dBm. Move the device, wait for the value to settle, and compare.
¶ Getting started
Follow the Getting started guide to connect the device to Wi-Fi and complete initial configuration.
¶ Optional (user installable) temperature sensor
Pow-P1 boards can accommodate a user-installed temperature sensor, type TMP36GRT (U6 on the board). This is an analog temperature sensor.
User should also install a 100 nF decoupling capacitor in the allocated position (C11).
To activate the temperature sensor, user must change the hardware setting:
- Add "/vendor" to the URL and select "Generic ESP32-S2" and "GPIO16" from the dropdown lists:
- Click "Save"
- Open the Config page
- You will now see a modified "Hardware" tile, with a field named "Analog temp", which must be set to "5" (corresponding to "GPIO5" marked on the PCB):
- In the "User interface" tile, ensure that "Temperature plot" is set to "Auto" or "Enabled":
- Click the blue "Save" button (bottom right) to save the changes.