diff --git a/radio/radio.py b/radio/radio.py
new file mode 100755
index 0000000..e3b513c
--- /dev/null
+++ b/radio/radio.py
@@ -0,0 +1,28 @@
+'''
+Simple class for a two way half duplex radio link. One end of the link is the master device,
+meaning the only end which sends unsolicited messages. The slave only transmits in response to
+such a message. Modify RadioSetup to match your hardware, channel and payload size (in bytes, 1-32).
+master = TwoWayRadio(True, **RadioSetup)
+slave = TwoWayRadio(False, **RadioSetup)
+'''
+import pyb
+from nrf24l01 import NRF24L01, POWER_3, SPEED_250K
+
+RadioSetup = { "channel": 100, "payload_size": 8, "spi_no": 1, "csn_pin": 'X5', "ce_pin": 'Y11'}
+
+class TwoWayRadio(NRF24L01):
+    pipes           = (b'\xf0\xf0\xf0\xf0\xe1', b'\xf0\xf0\xf0\xf0\xd2')
+    def __init__(self, master, channel, payload_size, spi_no, csn_pin, ce_pin):
+        super().__init__(pyb.SPI(spi_no), pyb.Pin(csn_pin), pyb.Pin(ce_pin),channel = channel,payload_size = payload_size)
+        if master:
+            self.open_tx_pipe(TwoWayRadio.pipes[0])
+            self.open_rx_pipe(1, TwoWayRadio.pipes[1])
+        else:
+            self.open_tx_pipe(TwoWayRadio.pipes[1])
+            self.open_rx_pipe(1, TwoWayRadio.pipes[0])
+        self.set_power_speed(POWER_3, SPEED_250K) # Best range for point to point links
+        self.start_listening()
+
+    def start_listening(self):
+        super().start_listening()
+        pyb.delay(1) # Seems to improve reliability
diff --git a/watchdog/wdog.py b/watchdog/wdog.py
new file mode 100644
index 0000000..f82e19c
--- /dev/null
+++ b/watchdog/wdog.py
@@ -0,0 +1,32 @@
+# Class for pybord watchdog timer
+import stm, pyb
+
+@micropython.asm_thumb
+def clz(r0):
+    clz(r0, r0) # return no. of leading zeros in passed integer
+
+class wdog(object):
+    def start(self, ms):
+        assert ms <= 32768 and ms >= 1, "Time value must be from 1 to 32768mS"
+        prescaler = 23 - clz(ms -1)
+        div_value = ((ms << 3) -1) >> prescaler
+        stm.mem16[stm.IWDG + stm.IWDG_KR] = 0x5555
+        stm.mem16[stm.IWDG + stm.IWDG_PR] = (stm.mem16[stm.IWDG + stm.IWDG_PR] & 0xfff8) | prescaler
+        stm.mem16[stm.IWDG + stm.IWDG_RLR] = (stm.mem16[stm.IWDG + stm.IWDG_RLR] & 0xf000) | div_value
+        stm.mem16[stm.IWDG + stm.IWDG_KR] = 0xcccc
+    def feed(self):
+        stm.mem16[stm.IWDG + stm.IWDG_KR] = 0xaaaa
+
+def test():
+    led = pyb.LED(2)
+    led1 = pyb.LED(3)
+    dog = wdog()
+    dog.start(1000)
+    for x in range(10):
+        led.toggle()
+        pyb.delay(500)
+        dog.feed()
+    dog.start(4000)
+    for x in range(20):
+        led1.toggle()
+        pyb.delay(500)