diff --git a/Makefile b/Makefile
index bab0553..eb96568 100644
--- a/Makefile
+++ b/Makefile
@@ -32,6 +32,13 @@ USEMODULE += shell_commands
 # additional modules for debugging:
 USEMODULE += ps
 
+#choose tiny dtls stack 
+#if errors, disable
+USEMODULE += tinydtls_sock_dtls
+CFLAGS += -DDTLS_PSK
+# when using plain CoAP. Uncomment the next line to fix this.
+CFLAGS += -DGCOAP_PDU_BUF_SIZE=256
+
 # Comment this out to disable code in RIOT that does safety checking
 # which is not needed in a production environment but helps in the
 # development process: