PulseTAC

Description

PulseTAC is used as a water meter but also as a gas and electricity meter and works with any external meter with pulse output. The acronym PulseTAC stands for "Pulse Transporter And Counter".
It has three simultaneous channels transmitted over very long distances using a network cable and the RS422/RS485 standards.
It is composed of two very small (approx 4x4.5cm) junction boxes: the sender and the receiver/controller which integrates an ESP8266 connected to the WiFi for IoT applications.
PulseTAC is very flexible and designed both for situations where the WiFi network reaches the meters or not.
The sender integrates three separate switch debouncers with ESD protected inputs. The power for the junction boxes can be supplied anywhere along the Ethernet cable or at the ends. The ESP8266 controller in the receiver/controller junction box can be equipped with Tasmota firmware for pulse counting and MQTT protocol support or with customized firmware.

Details

If the wifi signal in your home reaches the meters, you can connect the pulse output of the meters to the sender and keep the receiver/controller close with a short patch cable. If instead the wifi signal cannot reach the meter room, you can use a cable, even very long if necessary, and place the receiver/controller in another room or building where your wifi signal is present.

Sender

Receiver/Controller

Bill of materials of Sender board

U1: Maxim MAX6817EUT+T
U2: Maxim MAX6816EUS+T
U3, U4, U5: Renesas ISL3295EIHZ-T
U6: CUI Inc. VXO7803-500-M
R1, R2, R3: 1K 1/8W SMD 0805
R4: 68 ohm 1/8W SMD 0805
C1, C2, C3, C4, C5: Wurth 885012207098 0.1uF MLCC SMD 0805
C6: Taiyo Yuden UMK316BBJ106KL-T 10uF MLCC SMD 1206
C7, C8: TDK C2012X5R1A226K125AB 22uF MLCC SMD 0805
L1: Pulse Electronics PA4321.333NLT
J1: Cui Devices TB006-508-06BE 6 pin terminal block
J2: Amphenol RJCSE-5085-01 RJ45 SMD connector
Bill of materials of Receiver/Controller board

U1, U2, U3: Renesas ISL3280EIHZ-T
U4: ESP-03 1MB flash ESP8266 controller
U6: CUI Inc. VXO7803-500-M
R1, R2, R3: 100 ohm 1% 1/8W SMD 0805
R4: 68 ohm 1/8W SMD 0805
R5, R6, R7, R9: 10K 1/8W SMD 0805
R8: 0 ohm solder joint
R10: 0 ohm solder joint
C1, C2, C3, C4: Wurth 885012207098 0.1uF MLCC SMD 0805
C6: Taiyo Yuden UMK316BBJ106KL-T 10uF MLCC SMD 1206
C7, C8: TDK C2012X5R1A226K125AB 22uF MLCC SMD 0805
L1: Pulse Electronics PA4321.333NLT
P1: 6 pins header 2.54mm
J2: Amphenol RJCSE-5085-01 RJ45 SMD connector

The 6 pins header P1 is used to connect an external FTDI programmer to flash the ESP8266 firmware. The pinout is:

1: 3.3V
2: GPIO0 (connect to pin 3 with a jumper to enter flash mode)
3: GND
4: TXD
5: RXD
6: GND

The GPIO assignment of the ESP8266 is:

GPIO14: Pulse Input 1 (counter1)
GPIO12: Pulse Input 2 (counter2)
GPIO13: Pulse Input 3 (counter3)
Using the Tasmota firmware, integration with home automation is very simple thanks to the MQTT protocol.
The Tasmota configuration template for PulseTAC is the following:

{"NAME":"Smart Meters","GPIO":[0,0,0,0,0,0,0,0,43,44,42,0,0],"FLAG":15,"BASE":18}

Files

Controller_Schematic.jpg

Controller schematic

JPEG Image - 651.34 kB - 07/22/2020 at 13:48

Preview

Sender_Schematic.jpg

Sender schematic

JPEG Image - 535.45 kB - 07/22/2020 at 13:48

Preview

sender_box_partA.stl

Sender Box partA 3D print STL file

Standard Tesselated Geometry - 109.85 kB - 07/22/2020 at 13:46

Download

sender_box_partB.stl

Sender Box partB 3D print STL file

Standard Tesselated Geometry - 135.04 kB - 07/22/2020 at 13:46

Download

controller_box_partA.stl

Controller Box partA 3D print STL file

Standard Tesselated Geometry - 109.07 kB - 07/22/2020 at 13:46

Download

Discussions

appz wrote 07/23/2020 at 00:07

As I see you use Ethernet cable like UART interface. Isnt It?

Are you sure? yes | no

iacot1 wrote 07/23/2020 at 00:43

Hello,

it is not exactly a uart interface because the impulses are sent on the cable as they are after the debounce, and, with the frequencies involved, very large distances without distortion are possible

Are you sure? yes | no

appz wrote 07/25/2020 at 00:23

Interesting. How long distance is possible?

without distortion - Did you mean clear mendr like square signale wave?

Are you sure? yes | no

iacot1 wrote 07/25/2020 at 01:17

For the distance you can refer to this annex: https://en.wikipedia.org/wiki/File:RS-422_CableLength-DataRate.png
You can see further details on RS422/RS485 data rates and distances on Maxim application note AN3884 or similar application notes from other producers like Renesas.
Further considerations about distortion and signal skews can be found on Renesas RS-485 transceiver tutorial.

Are you sure? yes | no

Dan Maloney wrote 07/22/2020 at 21:20

I can see a lot of applications for something like this. Nice work.

Are you sure? yes | no

iacot1 wrote 07/23/2020 at 00:22

Hello Dan,

thanks a lot for your message!

Are you sure? yes | no

PulseTAC

Description

Details