diff --git a/week12_telegram_bots/Peter Sergeev Homework/mysubstratedb.py b/week12_telegram_bots/Peter Sergeev Homework/mysubstratedb.py
new file mode 100644
index 0000000..2b421ac
--- /dev/null
+++ b/week12_telegram_bots/Peter Sergeev Homework/mysubstratedb.py	
@@ -0,0 +1,68 @@
+import sqlalchemy
+import pyodbc
+from sqlalchemy import create_engine
+from sqlalchemy import Column, Integer, String, DateTime, Float
+from sqlalchemy.sql import func
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy_utils import database_exists, create_database
+from sqlalchemy.orm import sessionmaker, Session
+
+
+CONNECTION_STR = "mssql+pyodbc://user:password@127.0.0.1/testDB?driver=SQL+Server"
+
+# create db
+Base = declarative_base()
+class Transaction(Base):
+    __tablename__ = 'Transactions'
+
+    id = Column(Integer, primary_key=True)
+    fromAddr = Column(String)
+    Destination = Column(String)
+    Amount = Column(Float)
+    Module = Column(String)
+    Method = Column(String)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+
+    def __repr__(self):
+        str = f"Transaction(fromAddr='{self.fromAddr}', Destination='{self.Destination}',\
+              Amount='{self.Amount}', Module='{self.Module}, Method={self.Method}, 'created_at={self.created_at}')"
+        return str
+
+# write data to db
+def writeData(data):
+    
+    engine = create_engine(CONNECTION_STR)
+    if not database_exists(engine.url):
+        create_database(engine.url)  
+
+    Session = sessionmaker(engine)
+    session = Session()
+    new_trx = Transaction(
+
+        fromAddr = data['Signature'],
+        Destination = data['Dest'],
+        Amount = data['Amount'],
+        Module = data['Pallet'],
+        Method = data['Call'],
+    )
+
+    session.add(new_trx)
+    print(f'\nExecuting add query:\n', new_trx)
+    session.commit()
+
+
+# some testing + table creation
+
+'''
+trx = Transaction(fromAddr=1, Destination=2011, Amount=1000000, Module='Balances', Method='Transfer')
+engine = create_engine(CONNECTION_STR)
+if not database_exists(engine.url):
+    create_database(engine.url)
+Base.metadata.create_all(engine)
+
+Session = sessionmaker(engine)
+with Session.begin() as session:
+    session.add(trx)
+    trxs = session.query(Transaction).all()
+    print(trxs)
+'''
diff --git a/week12_telegram_bots/Peter Sergeev Homework/substrate.py b/week12_telegram_bots/Peter Sergeev Homework/substrate.py
new file mode 100644
index 0000000..ec67262
--- /dev/null
+++ b/week12_telegram_bots/Peter Sergeev Homework/substrate.py	
@@ -0,0 +1,144 @@
+import substrateinterface as sub
+from telebot import TeleBot
+from threading import Thread
+from mysubstratedb import writeData
+
+# TG bot key
+bot = TeleBot('KEY')
+# set of users who will receive blockchain updates
+ids = dict()
+
+
+# handle subscription
+def subscription_handler(obj, update_nr, subscription_id):
+    
+    # Retrieve transactions in block
+    result = substrate.get_block(block_number=obj['header']['number'])
+    parse_data(result)
+
+    # for later use, currently use 100 for testing
+    if update_nr > 100:
+        return {'message': 'Subscription will cancel when a value is returned', 'updates_processed': update_nr}
+           
+
+# parse block data
+def parse_data(result):
+    data = dict()
+
+    for extrinsic in result['extrinsics']:
+
+        if extrinsic.value["call"]["call_module"] in ['Crowdloan', 'Balances']:
+
+            if 'address' in extrinsic.value:
+                signed_by_address = extrinsic.value['address']
+            else:
+                signed_by_address = None
+
+            data['Pallet'] = extrinsic.value["call"]["call_module"]
+            data['Call'] = extrinsic.value["call"]["call_function"]
+            data['Signature'] = signed_by_address
+
+            # Loop through call params
+            for param in extrinsic.value["call"]['call_args']:
+
+                if param['type'] == 'Balance' or param['type'] == 'BalanceOf':
+                    #param['value'] = '{:.2f} {}'.format(param['value'] / 10 ** substrate.token_decimals, substrate.token_symbol)
+                    data['Amount'] = param['value'] / 10 ** substrate.token_decimals
+
+                elif param['type'] == 'LookupSource' or param['type'] == 'ParaId':
+                    data['Dest'] = param['value']
+                
+            writeData(data)
+            
+            # send messages if user threshold is met. 
+            if data['Pallet'] == 'Balances':
+                s = '{:.2f} DOT were transferred to account {}'.format(data['Amount'], data['Dest'])
+                print(s)
+                for id, threshold in ids.items():
+                    if data['Amount'] >= threshold:
+                        bot.send_message(id, s)
+
+            elif data['Pallet'] == 'Crowdloan':
+                s = '{:.2f} DOT were contributed to parachain_id {}'.format(data['Amount'], data['Dest'])
+                print(s)
+                for id, threshold in ids.items():
+                    if data['Amount'] >= threshold:
+                        bot.send_message(id, s)
+    
+    
+# bot functions
+@bot.message_handler(commands=['start'])
+def save_id(message):
+    
+    # ids.add(message.from_user.id) 
+    # # add key to a dict
+    ids[message.from_user.id] = 0
+    print(ids)
+    sent = bot.send_message(message.from_user.id, 'Hi, this is a polkadot blockchain bot\
+        which reads realtime transfers and crowdloan contributions from the blockchain')
+    sent = bot.send_message(message.from_user.id, 'Please input desired threshold for native currency amount (DOT) in decimals')
+    bot.register_next_step_handler(sent, threshold)
+
+
+def threshold(message):
+    try: 
+        float(message.text)
+    except ValueError:
+        sent = bot.send_message(message.from_user.id, 'I asked for a number... Tyr one more time')
+        bot.register_next_step_handler(sent, threshold)
+
+    # t.append(float(message.text))
+    ids[message.from_user.id] = float(message.text)
+    bot.send_message(message.from_user.id, 'Subscribing to block headers...')
+
+
+@bot.message_handler(commands=['stop'])
+def stop(message):
+    ids.pop(message.from_user.id, None)
+    bot.send_message(message.from_user.id, 'Done, you will now stop receiveing blockchain updates')
+
+
+if __name__ == '__main__':
+
+    # threshold
+    # t = [0]
+
+    # node connection
+    substrate = sub.SubstrateInterface(
+        url="wss://rpc.polkadot.io",
+        ss58_format=0,
+        type_registry_preset='substrate-node-template'
+    )
+    print("substrate initialized")
+
+    # create threade for node connection. 
+    thread = Thread(target = substrate.subscribe_block_headers, args=(subscription_handler, ))
+    thread.start()
+    print("Thread created")
+    bot.infinity_polling()
+
+    
+
+# tbd: batch transactions
+'''
+# multiple calls in one transaction (not available atm)
+
+    if param['type'] == 'Vec<Call>': 
+        for j in param['value']:
+            print 
+            for k in j['call_args']:
+                if k['type'] == 'Balance' or k['type'] == 'ParaId':
+                    k['value'] = '{} {}'.format(k['value'] / 10 ** substrate.token_decimals, substrate.token_symbol)
+                print("{}: {}".format(k['name'], k['value']))
+    else:
+        print("{}: {}".format(param['name'], param['value']))
+
+
+a = [{'call_index': '0x0001', 'call_function': 'remark', 'call_module': 'System', 'call_args': [{'name': 'remark', 'type': 'Bytes', 'value': '2031#0x4439fba228ad9a1c73af384af7119782123aa6f6d55592f07bf82da5b919c0c7'}], 'call_hash': '0x602962dc0688f843a855b3ab0891506a9f8de0d555bbb6cdef2113577498b829'}, {'call_index': '0x0500', 'call_function': 'transfer', 'call_module': 'Balances', 'call_args': [{'name': 'dest', 'type': 'LookupSource', 'value': '13wNbioJt44NKrcQ5ZUrshJqP7TKzQbzZt5nhkeL4joa3PAX'}, {'name': 'value', 'type': 'Balance', 'value': 60000000000}], 'call_hash': '0x8684d51fda246d58daad60a8b4ce094bbbb468b28279810f38bf65ed2474a76b'}] 
+for x in a:
+    # print(x['call_args'])
+    for y in x['call_args']:
+        if y['type'] == 'Balance':
+            y['value'] = '{} {}'.format(y['value'] / 10 ** substrate.token_decimals, substrate.token_symbol)
+        print (y['value'])
+'''