diff --git a/Cal4at3 b/Cal4at3
new file mode 100644
index 0000000..871b61e
--- /dev/null
+++ b/Cal4at3
@@ -0,0 +1,13 @@
+#calibrate 4 channels + 13 to 3L/min 
+
+
+import serial
+import time
+
+ser = serial.Serial('com3')
+ser.boudrate = 9600
+ser.flush()
+
+print("Calibrating")
+setFlow 0:3;1:3;2:3;3:3;4:3;13:3;
+print("Calibration Complete") 
diff --git a/README.md b/README.md
index e07a135..ba2e82c 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,10 @@
 # olfactometer
-Set of python scripts used to automate olfacotmeter tasks at SWRI
+Set of python scripts used to automate olfacotmeter tasks at SWRI.
+All experiments will start and end by emitting clean air for 1 second, so that no cross-contamination may occur between experiments
+
+USAGE
+
+DEPENDENCIES
+   - pyserial: helps python interact with serial ports. can be installed with "pip install pyserial" on the computer that will use the olfactometer.
+   - time: helps add pauses between opening valves when needed. As far as I am aware, this module comes with any default python installation.
+SCRIPTS
\ No newline at end of file
diff --git a/example.py b/example.py
new file mode 100644
index 0000000..d384f16
--- /dev/null
+++ b/example.py
@@ -0,0 +1,20 @@
+import serial
+import time
+ser = serial.Serial('com4') #defines the port that will be used (how do we know that?)
+ser.boudrate = 9600 #sets the speed at which data will be transferred to ARDUINO (default?)
+ser.flush() # flushes the port buffer 
+input("Press any key to start\n") #wait
+print("Now we are going to generate an odour on channel 1")
+print('The odour "duration" of 200ms is controlled by Sniff-0 ')
+input("Press any key to generate the odour\n")
+ser.write(b'setchannel 1\r')
+ser.write(b'openvalvetimed 200\r')
+print("Now the clean air channel is going to be opened")
+print("Clean air will be delivered for 1000ms")
+input("Press any key to open clean air\n")
+ser.write(b'setchannel 0\r')
+ser.write(b'setvalve 1\r')
+time.sleep(1)
+ser.write(b'setvalve 0\r')
+print("End")
+ser.close()
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diff --git a/experiments_yaml/clean.yml b/experiments_yaml/clean.yml
new file mode 100644
index 0000000..74cc530
--- /dev/null
+++ b/experiments_yaml/clean.yml
@@ -0,0 +1,10 @@
+parameters:
+  port: "com3"
+  constant_flow_channel_id: 0
+  constant_flow_rate: 2
+  calibration: no
+
+clean:
+  seconds: 20
+  channels:
+    13: 1
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diff --git a/experiments_yaml/expt1.yml b/experiments_yaml/expt1.yml
new file mode 100644
index 0000000..465b10e
--- /dev/null
+++ b/experiments_yaml/expt1.yml
@@ -0,0 +1,23 @@
+parameters:
+  port: "com3"
+  constant_flow_channel_id: 0
+  constant_flow_rate: 2
+  calibration: no
+
+clean:
+  seconds: 20
+  channels:
+    13: 1
+
+test1:
+  seconds: 20
+  channels:
+    1: 1
+    2: 1
+    3: 1
+
+      
+
+
+  
+ 
diff --git a/olfactometer_yaml.py b/olfactometer_yaml.py
new file mode 100644
index 0000000..47426a0
--- /dev/null
+++ b/olfactometer_yaml.py
@@ -0,0 +1,158 @@
+import serial
+import argparse
+import yaml
+import sys
+import time
+
+def parse():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-i',"--input",help="Name of the yaml file with the experiment",default=None)
+    args = parser.parse_args()
+    return args
+
+def set_parameters(yml):
+    if list(yml.keys())[0]!="parameters": # In python 3, dict_keys object is not subscriptable
+       print ("First key in input file is not parameters. Exiting.")
+       sys.exit()
+    else:
+       port=yml["parameters"]["port"]
+       constant_flow_rate=yml["parameters"]["constant_flow_rate"]
+       constant_flow_id=yml["parameters"]["constant_flow_channel_id"]
+       calibration=yml["parameters"]["calibration"]
+       print("Olfactometer will be runing from port ", port)
+       print("Constant flow will come from channel ", constant_flow_id)
+       print("Constant flow will be set at ", constant_flow_rate," SPLM")
+       if calibration==True:
+         print("Channels will be calibrated before starting each experiment.")
+       else:
+         print("Calibration will NOT be done for any channels. Make sure it is already done.") 
+         z=input("Press enter to continue or ctrl+C to exit.")
+       return port, constant_flow_rate, constant_flow_id, calibration
+   
+def check_expts(yml):
+    if yml["parameters"]["calibration"]==False:
+      print("Calibration has been done externally. Displayed flow rate values may not be true")
+    for key in list(yml.keys())[1:]: # first key is ALWAYS the parameters   
+       print("Checking step:",key, "...")
+       print("Run time:",yml[key]["seconds"],"seconds")
+       for channel in list(yml[key]["channels"].keys()):
+         print("Channel",channel,"will run at",yml[key]["channels"][channel],"SPLM")
+    return
+
+def run_calibration(ser,channel,flow):
+   if ser is None:
+      print("Cannot verify calibration in emulator mode. Assuming it was successful.")
+      return True
+
+   cmd_str="setverbose 1"
+   ser_exec(cmd)
+   cmd_str="setflow "+str(channel_id)+":"+str(flow_i)+";"
+   ser.exec(cmd)
+   
+   readback=ser_listen(ser)
+   if readback is None:
+      return False
+
+   if ("Result" in readback):
+      print (readback)
+      readback=ser_listen(ser)
+      if readback is None:
+         return False
+      if ("*OK" in readback):
+         print('Calibration completed successfully')
+         return True
+
+def run_expt(yml,ser, constant_flow_rate, constant_flow_id, calibration):
+    # 0) Calibrate the constant flow channel if required
+    if calibration is True:
+       print("calibrating constant flow")
+       outcome=run_calibration(ser,constant_flow_id,constant_flow_rate)
+       print(outcome)
+       if outcome is False:
+          print("constant flow calibration failed. Exiting.")
+          return
+
+    # 1) Open constant flow
+    cmd_str="setchannel "+str(constant_flow_id)
+    ser_exec(ser,cmd_str)
+
+    cmd_str="setvalve 1"
+    ser_exec(ser,cmd_str)
+
+    # 2) Run experiments 
+    for key in list(yml.keys())[1:]: # first key is ALWAYS the parameters
+       z=input("Press Enter to start: "+key)
+       timeopenvalve=yml[key]["seconds"] #This is the time this experiment will run for
+
+       # 2.1) Calibrate flows of odorant channels if required
+       if calibration is True:
+          print("calibrating odorant channels")
+          for channel in list(yml[key]["channels"].keys()):
+              flow=yml[key]["channels"][channel]
+              outcome=run_calibration(ser,channel,flow)
+              print(channel,flow,outcome)
+              if outcome is False:
+                 print("Calibration of channel",channel,"failed. Exiting.")
+                 return
+       
+       # 2.2) Open the odorant channels (timed)
+       time_ms=timeopenvalve*1000
+       cmd_str="openmultivalvetimed "+str(time_ms)+" "+";".join(map(str,list(yml[key]["channels"].keys())))
+       ser_exec(ser,cmd_str)
+      
+       # 2.3) Once all commands are submitted, wait for the execution time + 10 seconds to catch up. 
+       time.sleep(timeopenvalve+10)
+           
+       
+    # 3) Close the constant flow
+    cmd_str="setchannel "+str(constant_flow_id)
+    ser_exec(ser,cmd_str)
+
+    cmd_str="setvalve 0"
+    ser_exec(ser,cmd_str)
+    return
+
+def ser_exec(ser,cmd_str):
+    print("WRITING TO SERIAL: ", cmd_str)
+    if ser is not None:
+       cmd_bytes=(cmd_str+"\r").encode()
+       ser.write(cmd_bytes)
+    return
+
+def ser_listen(ser):
+   readback=None
+   waiting_time=0
+   readback = ser.readline().decode('utf-8')
+   while(readback is None):
+      readback = ser.readline().decode('utf-8')
+      time.sleep(1)
+      waiting_time+=1
+      if waiting_time>60:
+         print("instrument is taking too long to reply. Aborting.")
+         break
+   return readback
+      
+if __name__=="__main__":
+    args=parse()
+    with open(args.input, 'r') as file:
+        try:
+          yml = yaml.safe_load(file)
+          print(yml)
+        except Exception as error:
+          print("The input file has formatting errors.")
+          print(error)
+          sys.exit()
+        else:
+           port, constant_flow_rate, constant_flow_id, calibration=set_parameters(yml)
+           try:
+              ser = serial.Serial(port)
+           except:
+              print("Serial Port ", port, " cannot be reached.")
+              print("Running in emulator mode.")
+              ser=None
+              z=input("Press enter to continue or CTRL+C to break execution.")
+           check_expts(yml)
+           run_expt(yml,ser, constant_flow_rate, constant_flow_id, calibration)
+           
+
+    
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