diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000000..f617a72f1c
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,6 @@
+{
+    "files.associations": {
+        "string.h": "c",
+        "queue.h": "c"
+    }
+}
\ No newline at end of file
diff --git a/py/send_message.py b/py/send_message.py
index a56f66487c..59bce3e9c6 100755
--- a/py/send_message.py
+++ b/py/send_message.py
@@ -41,6 +41,7 @@
     FirmwareVersionOutdatedException,
     u2fhid,
     bitbox_api_protocol,
+    PhysicalLayer,
 )
 
 import u2f
@@ -1555,6 +1556,31 @@ def run(self) -> int:
         self._device.close()
         return 0
 
+def connect_to_simulator_bitbox(debug: bool) -> int:
+    class Simulator(PhysicalLayer):
+        def write(self, data: bytes) -> None:
+            raise Exception(f"TODO: write {data.hex()} to simulator")
+
+        def read(self, size: int, timeout_ms: int) -> bytes:
+            raise Exception(f"TODO: read {size} bytes from simulator")
+
+    simulator = Simulator()
+
+    device_info = {
+        "serial_number": "v9.15.0",
+        "path": "",
+        "product_string": "BitBox02BTC",
+    }
+    noise_config = bitbox_api_protocol.BitBoxNoiseConfig()
+    bitbox_connection = bitbox02.BitBox02(
+        transport=u2fhid.U2FHid(simulator), device_info=device_info, noise_config=noise_config,
+    )
+    try:
+        bitbox_connection.check_min_version()
+    except FirmwareVersionOutdatedException as exc:
+        print("WARNING: ", exc)
+
+    return SendMessage(bitbox_connection, debug).run()
 
 def connect_to_usb_bitbox(debug: bool, use_cache: bool) -> int:
     """
@@ -1643,6 +1669,7 @@ def main() -> int:
     parser = argparse.ArgumentParser(description="Tool for communicating with bitbox device")
     parser.add_argument("--debug", action="store_true", help="Print messages sent and received")
     parser.add_argument("--u2f", action="store_true", help="Use u2f menu instead")
+    parser.add_argument("--simulator", action="store_true", help="Connect to the BitBox02 simulator instead of a real BitBox02")
     parser.add_argument(
         "--no-cache", action="store_true", help="Don't use cached or store noise keys"
     )
@@ -1663,6 +1690,9 @@ def main() -> int:
             return u2fapp.run()
         return 1
 
+    if args.simulator:
+        return connect_to_simulator_bitbox(args.debug)
+
     return connect_to_usb_bitbox(args.debug, not args.no_cache)
 
 
diff --git a/test/unit-test/simulator b/test/unit-test/simulator
new file mode 100755
index 0000000000..21dfa588d2
Binary files /dev/null and b/test/unit-test/simulator differ
diff --git a/test/unit-test/simulator.c b/test/unit-test/simulator.c
new file mode 100644
index 0000000000..427a498e64
--- /dev/null
+++ b/test/unit-test/simulator.c
@@ -0,0 +1,72 @@
+// Copyright 2023 Shift Cryptosecurity AG
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+
+/*
+infinite loop reading stdin line by line
+each line is e.g. a hex encoded string containing the USB message that is sent by the host (e.g. the USB msgs that is sent by the bitbox-api-rs client library)
+process the usb message
+print the response usb messages to stdout, again one message per line, hex encoded
+
+somehow expose a usb connection to this c program. There read the messages from stdin and write the responses to stdout.
+When read the message, call the message handling function of the firmware so that it takes care of everything and returns the output
+*/
+
+#include <stdio.h>
+#include "../../src/usb/usb_processing.h"
+
+#define USB_DESC_HID_EP_SIZE 0x40
+#define USB_REPORT_SIZE USB_DESC_HID_EP_SIZE
+#define USB_HID_REPORT_IN_SIZE USB_REPORT_SIZE
+#define USB_HID_REPORT_OUT_SIZE USB_REPORT_SIZE
+
+char* get_usb_message(char* input) {
+    char* res = fgets(input, sizeof(input), stdin);
+    input[strcspn(input, "\n\r")] = 0;
+    return res;
+}
+
+void simulate_firmware_execution(char* input) {
+    //u2f_packet_process
+
+    //usb_processing_process
+    //chain of call: firmware_main_loop -> usb_processing_process -> _usb_consume_incoming_packets ->
+    // _usb_execute_packet
+    //usb_processing_process(usb_processing_hww());
+    /* First, process all the incoming USB traffic. */
+    //usb_processing_process(usb_processing_hww());
+    /*
+    * If USB has generated events at the application level,
+    * process them now.
+    */
+    //hww_process();
+
+    //usb_packet_process but it puts the packet into queue
+    //chain of call: usb_packet_process -> usb_processing_enqueue -> _build_packet
+    static uint8_t _out_report[USB_HID_REPORT_OUT_SIZE];
+    memccpy(_out_report, input, 0, sizeof(_out_report));
+    usb_packet_process((const USB_FRAME*)_out_report);
+}
+
+int main(void) {
+    char buffer[4096];
+    while (get_usb_message(buffer)) {
+        if (strcmp(buffer, "") == 0) {
+            break;
+        }
+        printf("received: %s\n", buffer);
+        simulate_firmware_execution(buffer);
+    }
+    return 0;
+}
\ No newline at end of file