Project Files of Raspberry Pi Zero W Library for Proteus: HX711 Scale, Web Page

RASPBERRY PI ZERO W LIBRARY FOR PROTEUS - V1.0 (BCM2835 1 GHZ, 512 MB, 2.4 GHZ WI-FI, 40-PIN HEADER, 65 X 30 MM)
YOUR PYTHON PROGRAM RUNS ON THE BOARD - DEMO: A WI-FI KITCHEN SCALE (HX711, 5 KG LOAD CELL, TM1637, A WEB PAGE)
Designed by The Engineering Projects www.TheEngineeringProjects.com

IMPORTANT LINKS
Article (read it first - pictures, step by step, every feature explained):
  https://www.theengineeringprojects.com/2026/10/raspberry-pi-zero-w-library-for-proteus-v1-0.html
Report a bug or suggest a feature (our forum):
  https://www.theengineeringprojects.com/forum/category/raspberry-pi-zero-w-proteus-library
The demo's parts are our libraries (included) - their articles:
  HX711:    https://www.theengineeringprojects.com/2026/10/hx711-load-cell-library-for-proteus-v1-0.html
  TM1637:   https://www.theengineeringprojects.com/2026/10/tm1637-7-segment-display-library-for-proteus-v1-0.html
  Laptop:   https://www.theengineeringprojects.com/2026/10/laptop-wifi-monitor-library-for-proteus.html
  Phone:    https://www.theengineeringprojects.com/2026/10/mobile-wifi-monitor-library-for-proteus.html
The earlier boards of this series:
  https://www.theengineeringprojects.com/2026/10/raspberry-pi-model-b-library-for-proteus.html
  https://www.theengineeringprojects.com/2026/10/raspberry-pi-1-model-b-plus-library-for-proteus.html
  https://www.theengineeringprojects.com/2026/10/raspberry-pi-2-model-b-library-for-proteus.html
  https://www.theengineeringprojects.com/2026/10/raspberry-pi-3-model-b-library-for-proteus.html
  https://www.theengineeringprojects.com/2026/10/raspberry-pi-3-model-b-plus-library-for-proteus.html
  https://www.theengineeringprojects.com/2026/10/raspberry-pi-3-model-a-plus-library-for-proteus.html
  https://www.theengineeringprojects.com/2026/10/raspberry-pi-4-model-b-library-for-proteus.html
  https://www.theengineeringprojects.com/2026/10/raspberry-pi-5-library-for-proteus.html
Support us (the libraries are free):
  https://www.theengineeringprojects.com/donate

FILE STRUCTURE
Raspberry-Pi-Zero-W-TEP-v1.0/
|-- Proteus Library Files/
|   |-- TEPHX711.LIB                                     90.7 KB   the HX711 + load cells (demo), to LIBRARY
|   |-- TEPLAPTOP.LIB                                    39.5 KB   the laptop (demo), to LIBRARY
|   |-- TEPMOBILE.LIB                                    13.1 KB   the phone (demo), to LIBRARY
|   |-- TEPRPI0W.LIB                                     49.4 KB   the Raspberry Pi Zero W, to LIBRARY
|   |-- TEPTM1637.LIB                                    84.8 KB   the TM1637 display (demo), to LIBRARY
|-- Proteus Model Files/
|   |-- TEPHX711.DLL                                    313.5 KB   the HX711 + load cells, to MODELS
|   |-- TEPNET.DLL                                       2.38 MB   the Pi + monitors + network, to MODELS
|   |-- TEPTM1637.DLL                                   284.0 KB   the TM1637 display, to MODELS
|   |-- TEPPi/python/                                   17.54 MB   Python 3.11.9 embeddable (33 files)
|   |-- TEPPi/runtime/                                  893.7 KB   TEP Pi runtime, gpiozero (62 files)
|-- Python Code/
|   |-- blink.py                                          0.3 KB   an LED on GPIO17 (the default)
|   |-- wifi_scale.py                                     7.2 KB   the demo
|-- Proteus Simulation/
|   |-- Pi-Zero-W-WiFi-Scale.pdsprj                      31.3 KB   the demo: Wi-Fi kitchen scale
|   |-- TEPHX711.DLL                                    313.5 KB   copy of the model
|   |-- TEPNET.DLL                                       2.38 MB   copy of the model
|   |-- TEPTM1637.DLL                                   284.0 KB   copy of the model
|   |-- wifi_scale.py                                     7.2 KB   the program of the demo
|-- README.txt                                          ~18.5 KB   this file
Total: 24.67 MB (unzipped). The source code of the models and of the TEP Pi runtime is not included.

WHAT IS IT?
The Raspberry Pi Zero W (2017) as one Proteus part - and a way to run Raspberry Pi programs in Proteus 8.5.
Proteus cannot run Raspberry Pi OS, so this library does not emulate Linux. It does what matters for electronics: the
board runs YOUR PYTHON PROGRAM (a .py file, the PROGRAM property) against the circuit on the sheet, with the Python
libraries a Pi uses for its pins, its I2C / SPI / UART buses and its Wi-Fi.
  * At Run the board starts Python 3.11 (included: the TEPPi folder) with our TEP Pi runtime, then your program.
    The program and Proteus work in lockstep: while the program runs, Proteus waits; while the program sleeps, waits
    for a pin, a bus or the network, Proteus runs. So time.sleep(0.5) is 0.5 s of simulation, a busy loop still moves
    the clock (about 5 us per GPIO call, as Python on the Zero W's 1 GHz ARM1176), and every edge is on time.
    time.time(), time.monotonic(), time.strftime() and datetime.now() follow the simulation's clock too.
  * Wi-Fi only (the Zero W has no Ethernet): wlan0 joins the network in the WIFISSID / WIFIPASS properties (default: our
    router "TEP-WiFi", password 12345678 - the network of our ESP32 / Arduino Wi-Fi parts and the Laptop / Mobile WiFi
    Monitors) as Raspberry Pi OS does at boot: 2.3 to 3.5 s after Run the Pi has 192.168.1.51 (192.168.1.(50 + the
    part's number)), the name raspberrypi.local. Sockets, http.server and urllib work on it.
  * Threads work (gpiozero's threads, your own threading.Thread, Timer, Queue, Lock): every wait is in simulation time;
    an error in a thread is printed as Python prints it ("Exception in thread ...").
  * The Python libraries for the pins (the same names, numbers and messages as on a Pi):
      RPi.GPIO      setmode, setup and output with one pin or a list (and a list of values), input, cleanup,
                    add_event_detect / event_detected / wait_for_edge with callbacks and bouncetime, PWM (software PWM
                    made by the board, steady while the program sleeps)
      gpiozero      LED, PWMLED, Button, OutputDevice, Buzzer, Servo, AngularServo, MotionSensor, DistanceSensor,
                    CPUTemperature and the rest (gpiozero 2.0.1, unchanged, on RPi.GPIO)
      spidev        SPI0 on GPIO11 (SCLK), GPIO10 (MOSI), GPIO9 (MISO), CE0 = GPIO8, CE1 = GPIO7, modes 0 to 3, up to
                    8 MHz; xfer / xfer2 take up to 4096 bytes (spidev's bufsiz), writebytes2 any length
      smbus2 / smbus  I2C bus 1 on GPIO2 (SDA) / GPIO3 (SCL) at 100 kHz, the Pi's 1.8 k pull-ups: read_byte,
                    write_byte, the byte / block reads and writes, write_quick, i2c_rdwr with i2c_msg; a device that
                    does not answer gives OSError [Errno 121] Remote I/O error
      serial        pyserial on /dev/serial0 (on a Zero W = /dev/ttyS0, the mini UART; /dev/ttyAMA0 is accepted too):
                    TXD GPIO14, RXD GPIO15, any baud rate, timeouts, back-to-back bytes
      1-Wire        the DS18B20's files under /sys/bus/w1/devices (w1-gpio on GPIO4), as the kernel makes them
      Adafruit_DHT, adafruit_dht + board   DHT11 / DHT22 on any GPIO
      socket        TCP and UDP on wlan0, http.server / socketserver, urllib.request, select
  * The Pi's own files: /proc/cpuinfo (Revision 9000c1, one ARMv6 processor), /proc/device-tree/model ("Raspberry Pi
    Zero W Rev 1.1"), the CPU temperature in /sys/class/thermal (gpiozero's CPUTemperature), /proc/loadavg,
    /proc/meminfo (512 MB).
  * The Pi Terminal (our TEP window, no Windows title bar): the shell prompt (pi@raspberrypi:~ $ python3 ...), the
    program's output (OUT) and errors (ERR, as Python prints them on a Pi), a line for input() (IN); its Board tab
    shows the GPIOs (BCM numbers), the LED, the supply pins and RESTART PROGRAM. Click the mini-HDMI socket or the
    processor to open it.
  * The LED: the green ACT LED by the power micro-USB (it flickers while the board boots and when the program prints);
    the Zero W has no PWR LED.
  * The header's supply pins power the modules wired to them, as on the bench: 5V, 3V3 and GND as logic levels (an
    analog VCC reading sees 5 V on either rail).
The board is drawn our way at its real size (65 x 30 mm, rounded corners, four mounting holes 58 x 23 mm apart) from
the Raspberry Pi Zero drawing: the 40-pin header along the top edge (unpopulated on the real board - drawn with the
header soldered in), the microSD slot on the left with the card out of the edge, the power corner with two inductors
and the buck converter, the BCM2835 with its 512 MB of RAM stacked on top, the Cypress CYW43438 Wi-Fi / Bluetooth chip
with its crystal, the PCB antenna by the camera connector, the RUN pads, the ACT LED, and along the bottom the mini-HDMI
socket and the two micro-USB sockets (USB, PWR IN). The 40 pins leave the top edge as one comb 50 thou apart, each with
a colour-coded tag: 5V red, 3V3 orange, GND black, GPIO green, I2C blue, SPI pink, UART purple, ID_SD / ID_SC grey.

ONE DEVICE (search "RASPBERRY" in Pick Devices):
  RASPBERRY PI ZERO W  "Raspberry Pi Zero W" V1.0 (category Microprocessor ICs > Raspberry Pi), prefix PI, model
                       TEPNET.DLL (with the TEPPi folder)
The same TEPNET.DLL also runs our Raspberry Pi Model B, 1 Model B+, 2 Model B, 3 Model B, 3 Model B+, 3 Model A+,
4 Model B and 5, our Ethernet and Wi-Fi shields, modules and boards and the Laptop / Mobile WiFi Monitors; it replaces
any older TEPNET.DLL (keep only this newest one in MODELS).

TEST STATUS
V1.0: verified in Proteus 8.5 on 24 Oct 2026 with the demo project as shipped. What the Proteus runs showed:
* Pi-Zero-W-WiFi-Scale: the program tares the empty scale at 107359 (the 5 kg cell's zero balance of 0.05 mV/V at
  AVDD 4.30 V), wlan0 joins TEP-WiFi and 2.9 s after Run it prints "serving on http://192.168.1.51:8000/"; the
  TM1637 shows 0.
* The laptop and the phone open the page: 0 g, the raw reading, the tare, the factor 429.50 per g - text links on the
  laptop, buttons on the phone.
* The HX711 pop-up's 500 g preset: "500 g (raw 322108)" and the display reads 500; the pop-up shows READ OK, channel A
  gain 128, 25 PD_SCK pulses, PD_SCK HIGH at most 10.0 us.
* The 1 kg preset: 1000 g; CAL 1 KG on the phone: "calibrated with 1 kg", the factor 429.49 per g; the TM1637's
  pop-up reads "1000", brightness 7 (14/16), write with auto-increment.
* The 2.5 kg preset: 2500 g; G / OZ on the laptop: 88.19 oz; TARE on the laptop: 0.00 oz and the display back at 0.
* The Board tab: the BCM2835 at 1 GHz, GPIO2 / GPIO3 pulled up, GPIO5 (DT) HIGH between results, GPIO6 (SCK) LOW,
  GPIO23 / GPIO24 let go to the module's pull-ups, 5V 5.00 V, 3V3 3.30 V, "No errors".
* Speed on our test PC: about 30 % of real time with the two pop-ups, the two monitors and the Pi Terminal open.

INSTALLATION (about 3 minutes)
1. Close Proteus. Extract the WHOLE ZIP to a normal folder (e.g. Desktop).
2. Copy everything in "Proteus Library Files" to the LIBRARY folder of Proteus, for example:
     C:\Program Files (x86)\Labcenter Electronics\Proteus 8 Professional\LIBRARY
   (on some PCs: C:\ProgramData\Labcenter Electronics\Proteus 8 Professional\LIBRARY - use the folder that already holds
   Proteus's own .LIB files). TEPRPI0W.LIB is the Pi; TEPHX711.LIB (the HX711 and the load cells), TEPTM1637.LIB (the
   display), TEPLAPTOP.LIB and TEPMOBILE.LIB are the demo's parts.
3. Copy everything in "Proteus Model Files" - the DLLs AND the TEPPi folder - to the MODELS folder:
     C:\Program Files (x86)\Labcenter Electronics\Proteus 8 Professional\MODELS
   TEPPi holds Python 3.11 and the TEP Pi runtime; the Pi finds it next to TEPNET.DLL, in MODELS or next to your
   project. Replace an older TEPNET.DLL and TEPPi folder (these are the newest).
4. Delete TEPRPI0W.IDX (and the .IDX of a part library you replaced) from the LIBRARY folder if it is there.
5. Start Proteus. In Pick Devices (P) search "RASPBERRY".
Nothing else to install: Python is in TEPPi (no Python on the PC needed, none is changed).

RUN THE DEMO
Keep the .py file and the DLLs beside the project in "Proteus Simulation" (the TEPPi folder in MODELS).
  Pi-Zero-W-WiFi-Scale.pdsprj - PI1 runs wifi_scale.py on Wi-Fi: U1 = a 5 kg bar load cell wired to U2 = an HX711
  module (red / black / white / green on E+ / E- / A- / A+; DT on GPIO5, SCK on GPIO6, VCC on 3V3), TM1 = a TM1637
  4-digit display (CLK on GPIO23, DIO on GPIO24, VCC on 3V3); PC1 = the Laptop WiFi Monitor and MOB1 = the Mobile WiFi
  Monitor on the same network. The HX711 and the display are the Advance parts: their pop-up windows open at Run.
  Press Run: the display shows "----" while the program tares the empty scale (the average of 5 results), wlan0 joins
  "TEP-WiFi" and the program serves its page; the display then shows the grams. Put a weight on the cell - the presets
  0 g, 100 g, 500 g, 1 kg, 2.5 kg and 5 kg in the HX711's pop-up, or the load cell's WEIGHT panel on the sheet. On the
  laptop or the phone open http://192.168.1.51:8000/ (Browser, the address, Go): the page shows the weight, the raw
  reading, the tare and the factor, with REFRESH, TARE (zero with what is on it now), CAL 1 KG (with 1 kg on the cell:
  the counts per gram are measured) and G / OZ (the page in grams or ounces). The display always shows grams, right-
  aligned, "OL" beyond 9999.
  The program is pure Python on RPi.GPIO: the HX711's read-out bit by bit (24 clocks + 1 for channel A, gain 128, SCK
  HIGH only a few microseconds), the TM1637's 2-wire bus as open-drain lines (a line is pulled LOW or let go to the
  module's pull-ups, the ACK read on the 9th clock), a weighing thread five times a second and http.server.

YOUR OWN PROGRAMS
Write the program with any editor, put the .py next to your project and set the Pi's PROGRAM property to its name (or
a full path). Start from Python Code\blink.py (an LED on GPIO17). Python's standard library is there; other
pure-Python packages work when you copy them next to your program. Use BCM numbers (GPIO.setmode(GPIO.BCM),
gpiozero's LED(17)) or GPIO.setmode(GPIO.BOARD) with the header's pin numbers.
A program that never sleeps and never touches a pin for 3 real seconds is left running on its own (the simulation
goes on); input() waits for a line typed in the Pi Terminal.

THE 40-PIN HEADER (BCM numbers - the tags on the board)
   1 3V3        2 5V          3 GPIO2 SDA    4 5V          5 GPIO3 SCL    6 GND         7 GPIO4 (1-Wire)
   8 GPIO14 TXD 9 GND        10 GPIO15 RXD  11 GPIO17     12 GPIO18      13 GPIO27     14 GND
  15 GPIO22    16 GPIO23     17 3V3         18 GPIO24     19 GPIO10 MOSI 20 GND        21 GPIO9 MISO
  22 GPIO25    23 GPIO11 SCLK 24 GPIO8 CE0  25 GND        26 GPIO7 CE1   27 ID_SD      28 ID_SC
  29 GPIO5     30 GND        31 GPIO6       32 GPIO12     33 GPIO13      34 GND        35 GPIO19
  36 GPIO16    37 GPIO26     38 GPIO20      39 GND        40 GPIO21
3.3 V logic: GPIO2 / GPIO3 have the Pi's 1.8 k pull-ups to 3.3 V; RPi.GPIO's pull-ups / pull-downs are weak drives.
ID_SD / ID_SC (27, 28, GPIO0 / GPIO1) are kept for a HAT's ID EEPROM; leave them free, as on a real Pi.
The RUN pads are drawn, not pins of the part.

PROPERTIES (double-click the Pi > Edit Properties)
  PROGRAM    the Python program (default blink.py; a name next to the project or a full path)
  AUTOOPEN   the Pi Terminal at Run: YES (default) or NO
  WIFISSID   the Wi-Fi network wlan0 joins (default TEP-WiFi)
  WIFIPASS   its password (default 12345678)
  PYTHON     a python.exe of your own (empty: TEPPi's)
  RUNTIME    the TEP Pi runtime folder (empty: TEPPi's)

TROUBLESHOOTING
* "TEP Pi: the TEPPi folder ... was not found": copy the TEPPi folder from "Proteus Model Files" into MODELS (or next
  to the project).
* "python3: can't open file": the PROGRAM file is not next to the project - put it there or give a full path.
* ModuleNotFoundError for a package: only the libraries above are built in; copy a pure-Python package's folder next to
  your program.
* The program waits for Wi-Fi forever: check WIFISSID / WIFIPASS (the simulation log says "not found" or "wrong
  password").
* The HX711 never gets ready, or reads nonsense: DT on an input, SCK on an output and LOW between read-outs; SCK HIGH
  for more than 60 us powers the chip down - the HX711's pop-up shows every read-out bit by bit.
* The display stays dark: the program must send the display-on command (0x88 + the brightness) after the digits;
  CLK and DIO are open-drain - let a line go (input) for a 1, never drive it HIGH while the chip answers the ACK.
* The weight is off: calibrate with a known weight (CAL 1 KG), and TARE with the empty scale.
* The page does not open: the address is http://192.168.1.51:8000/ (the port the program serves), and the program must
  have printed "serving on". A monitor sometimes needs Go a second time. Use the page's REFRESH link to see new
  values (the monitors' Reload repeats the last link, e.g. TARE).
* A paused simulation shows the SIMULATION LOG: click the Schematic Capture tab.

BUG REPORTS AND FEATURE REQUESTS
Please post them in our forum with a screenshot, the program, the Pi Terminal's text and the simulation log:
  https://www.theengineeringprojects.com/forum/category/raspberry-pi-zero-w-proteus-library

SUPPORT US
This library is free. If it saves you time, please support our work:
  https://www.theengineeringprojects.com/donate

WEBSITE
  https://www.theengineeringprojects.com/

LICENCES AND THIRD-PARTY NOTES
* The Raspberry Pi board model, the TEP Pi runtime, the Pi Terminal and the network (TEPNET.DLL, the compiled .pyc files
  in TEPPi\runtime with the stand-ins lgpio, RPi, smbus2, smbus, spidev, serial, Adafruit_DHT, adafruit_dht, board), the
  symbols and artwork (TEPRPI0W.LIB), the part models (TEPHX711 and TEPTM1637 .DLL / .LIB, the Laptop and Mobile WiFi
  Monitors' TEPLAPTOP.LIB / TEPMOBILE.LIB in TEPNET.DLL) and the demo program are made by The Engineering Projects.
  Our stand-ins follow the APIs of RPi.GPIO, lgpio, smbus2, py-spidev, pyserial, Adafruit_DHT and
  adafruit-circuitpython-dht; none of their code is copied. The source code of the models is not included (nor the
  runtime's: it ships compiled for the included Python 3.11).
* TEPPi\python is the official embeddable Python 3.11.9 for Windows (32-bit) from python.org, unchanged, under the
  Python Software Foundation License (TEPPi\python\LICENSE.txt).
* TEPPi\runtime\gpiozero is gpiozero 2.0.1.post3 and TEPPi\runtime\colorzero is colorzero 2.0, unchanged, under the BSD
  3-Clause licence (their LICENSE files in the dist-info folders).
* Proteus is a product of Labcenter Electronics and is not included. Raspberry Pi is a trademark of Raspberry Pi Ltd.
  This library is not made or endorsed by Raspberry Pi Ltd or Labcenter.

MODEL SCOPE AND LIMITS
Modelled: the 26 GPIOs of the 40-pin header (inputs, outputs, RPi.GPIO's pull-ups / pull-downs, edges, software PWM),
the I2C, SPI, UART, 1-Wire and DHT buses as the Pi's drivers drive them, the supply pins, Wi-Fi (wlan0: the join, DHCP,
TCP and UDP to every TEP network part), the ACT LED, a 0.5 s boot before the program starts, the Pi's /proc and /sys
files above, the Pi Terminal. Not modelled: Raspberry Pi OS (no desktop, no shell commands, no apt, no os.system),
Bluetooth, Wi-Fi scanning from the program, the mini-HDMI output, the camera connector, USB and USB OTG gadget modes,
the microSD card's files, the RUN pads, hardware PWM (GPIO18 is software PWM here), a HAT's ID EEPROM, C programs and C
extensions, the real CPU's speed (each GPIO call takes about 5 us; pure Python code takes no simulation time),
real-time jitter. The model's own choices: the board's IP address (192.168.1.51 for PI1), the boot time, the router;
the simulation runs below real time.

VERSION
TEP Raspberry Pi Zero W library V1.0 (Oct 2026). Device RASPBERRY PI ZERO W (TEPRPI0W.LIB / TEPNET.DLL with TEPPi:
Python 3.11.9 and the TEP Pi runtime 0.2). Demo program wifi_scale.py V1.0, blink.py.