diff --git a/flake.nix b/flake.nix
index 93ee5e8..13bafa8 100644
--- a/flake.nix
+++ b/flake.nix
@@ -9,7 +9,7 @@
     let 
       version = builtins.string 0 8 self.lastModifiedDate;
       supportedSystems = [ "x86_64-linux" "avr-none" ];
-      cflags = { mcu, chip_select, f_cpu }: ''-O -finline-functions -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -Wall -Werror -Wstrict-prototypes -DF_CPU=${f_cpu} -std=gnu99 -D__${chip_select}__=1 -mmcu=${mcu}'';
+      mcu_cflags = { mcu, chip_select, f_cpu }: ''-O -finline-functions -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -Wall -Werror -Wstrict-prototypes -DF_CPU=${f_cpu} -std=gnu99 -D__${chip_select}__=1 -mmcu=${mcu}'';
 
       attiny85 = { mcu = "attiny85"; chip_select = "AVR_ATtiny85"; f_cpu = "8000000"; };
       atmega32u4 = { mcu = "atmega32u4"; chip_select = "AVR_ATmega32u4"; f_cpu = "8000000"; };
@@ -29,13 +29,12 @@
         dontConfigure = true;
 
         buildPhase = ''
-          set -x
           for source in ${src}/*.c; do
               if [ -e $source ]; then
-                  ${gcc}/bin/gcc ${cflags} ${include_dirs} -c $source
+                  ${gcc} ${cflags} ${include_dirs} -c $source
               fi
           done
-          cp ${src}/*.h .
+          cp ${src}/*.h . || true
           '';
 
         installPhase = ''
@@ -45,23 +44,52 @@
           '';
       };
 
+      mkProgram = { pkgs, gcc, cflags, pname, psrc, pbuildInputs ? [] }:
+      pkgs.stdenv.mkDerivation rec {
+        name = pname;
+        src = psrc;
+
+        buildInputs = pbuildInputs;
+
+        include_dirs = pkgs.lib.concatStringsSep " " (map (dir: "-I${dir}/include") buildInputs);
+        object_files = pkgs.lib.concatStringsSep " " (map (dir: "${dir}/lib/*.o") buildInputs);
+
+        dontUnpack = true;
+        dontConfigure = true;
+
+        buildPhase = ''
+          set -x
+          for source in ${src}/*.c; do
+              if [ -e $source ]; then
+                  ${gcc} ${cflags} ${include_dirs} -c $source
+              fi
+          done
+
+          ${gcc} -o ${name} ${cflags} ${object_files} *.o
+          '';
+
+        installPhase = ''
+          mkdir -p $out/bin
+          cp ${name} $out/bin
+          '';
+      };
+
 
     in rec
     {
       defaultPackage."x86_64-linux" = 
         let
           pkgs = import nixpkgs { system = "x86_64-linux"; };
+          avr = pkgs.pkgsCross.avr.buildPackages;
         in pkgs.symlinkJoin {
           name = "avr-monorepo";
           paths = [
-            (packages."x86_64-linux"."flame" processor)
-            (packages."x86_64-linux"."prime-tx" processor)
-            (packages."x86_64-linux"."radio-rx" processor)
-            (packages."x86_64-linux"."interrupts" processor)
+            (packages."x86_64-linux"."prime-tx" { gcc = "${avr.gcc}/bin/avr-gcc"; cflags = mcu_cflags atmega32u4; })
+            (packages."x86_64-linux"."radio-rx" { gcc = "${avr.gcc}/bin/avr-gcc"; cflags = mcu_cflags atmega32u4; })
           ];
         };
 
-      packages."x86_64-linux"."dio-attiny85" = (packages."x86_64-linux"."dio" attiny85);
+      /* packages."x86_64-linux"."dio-attiny85" = (packages."x86_64-linux"."dio" attiny85); */
 
       /*
       packages."x86_64-linux"."dio" =
@@ -74,77 +102,158 @@
           name =
       */
 
-
-      /*
       packages."x86_64-linux"."dio" =
-        { mcu, chip_select, f_cpu }:
-        let
-          pkgs = import nixpkgs { system = "x86_64-linux"; };
-          avr = pkgs.pkgsCross.avr.buildPackages;
-        in pkgs.stdenv.mkDerivation rec {
-          name = "dio";
-          src = ./.;
-
-          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
-
-          installPhase = ''
-            mkdir $out
-            cp dio/dio.h $out/
-            '';
-        };
-        */
-
-      packages."x86_64-linux"."rng" =
+        { gcc, cflags }:
         let
           pkgs = import nixpkgs { system = "x86_64-linux"; };
         in mkLibrary {
           pkgs = pkgs;
-          gcc = pkgs.gcc;
-          cflags = "-Werror -Wall";
+          gcc = gcc;
+          cflags = cflags;
+          pname = "dio";
+          psrc = ./dio;
+        };
+
+      packages."x86_64-linux"."rng" =
+        { gcc, cflags }:
+        let
+          pkgs = import nixpkgs { system = "x86_64-linux"; };
+        in mkLibrary {
+          pkgs = pkgs;
+          gcc = gcc;
+          cflags = cflags;
           pname = "rng";
           psrc = ./rng;
         };
 
-        /*
-      packages."x86_64-linux"."rng" =
-        { mcu, chip_select, f_cpu }:
-        let
-          pkgs = import nixpkgs { system = "x86_64-linux"; };
-          avr = pkgs.pkgsCross.avr.buildPackages;
-        in pkgs.stdenv.mkDerivation rec {
-          name = "rng";
-          src = ./.;
-
-          buildInputs = [
-            (packages."x86_64-linux"."dio" { inherit mcu chip_select f_cpu; })
-          ];
-
-          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
-          INCLUDE_DIRS = pkgs.lib.concatStringsSep " " (map (dir: "-I${dir}") buildInputs);
-          OBJECT_FILES = pkgs.lib.concatStringsSep " " (map (dir: "${dir}/*.o") buildInputs);
-
-          buildPhase = ''
-            ${avr.gcc}/bin/avr-gcc ${CFLAGS} ${INCLUDE_DIRS} -o rng.o -c ${src}/rng/rng.c
-            '';
-
-          installPhase = ''
-            mkdir $out
-            cp rng/rng.h rng.o $out/
-            '';
-        };
-        */
-
       packages."x86_64-linux"."animation" =
+        { gcc, cflags }:
         let
           pkgs = import nixpkgs { system = "x86_64-linux"; };
         in mkLibrary {
           pkgs = pkgs;
-          gcc = pkgs.gcc;
-          cflags = "-Werror -Wall";
+          gcc = gcc;
+          cflags = cflags;
           pname = "animation";
           psrc = ./animation;
         };
 
+      packages."x86_64-linux"."sk9822" =
+        { gcc, cflags }:
+        let
+          pkgs = import nixpkgs { system = "x86_64-linux"; };
+        in mkLibrary {
+          pkgs = pkgs;
+          gcc = gcc;
+          cflags = cflags;
+          pname = "sk9822";
+          psrc = ./sk9822;
+          pbuildInputs = [
+            (packages."x86_64-linux"."dio" { inherit gcc cflags; })
+          ];
+        };
+
+      packages."x86_64-linux"."shift-register" =
+        { gcc, cflags }:
+        let
+          pkgs = import nixpkgs { system = "x86_64-linux"; };
+        in mkLibrary {
+          pkgs = pkgs;
+          gcc = gcc;
+          cflags = cflags;
+          pname = "shift-register";
+          psrc = ./shift-register;
+          pbuildInputs = [
+            (packages."x86_64-linux"."dio" { inherit gcc cflags; })
+          ];
+        };
+
+      packages."x86_64-linux"."spi" =
+        { gcc, cflags }:
+        let
+          pkgs = import nixpkgs { system = "x86_64-linux"; };
+        in mkLibrary {
+          pkgs = pkgs;
+          gcc = gcc;
+          cflags = cflags;
+          pname = "spi";
+          psrc = ./spi;
+          pbuildInputs = [
+            (packages."x86_64-linux"."dio" { inherit gcc cflags; })
+          ];
+        };
+
+      packages."x86_64-linux"."rfm" =
+        { gcc, cflags }:
+        let
+          pkgs = import nixpkgs { system = "x86_64-linux"; };
+        in mkLibrary {
+          pkgs = pkgs;
+          gcc = gcc;
+          cflags = cflags;
+          pname = "rfm";
+          psrc = ./rfm69hcw;
+          pbuildInputs = [
+            (packages."x86_64-linux"."dio" { inherit gcc cflags; })
+            (packages."x86_64-linux"."spi" { inherit gcc cflags; })
+          ];
+        };
+
+      packages."x86_64-linux"."display" =
+        { gcc, cflags }:
+        let
+          pkgs = import nixpkgs { system = "x86_64-linux"; };
+        in mkLibrary {
+          pkgs = pkgs;
+          gcc = gcc;
+          cflags = cflags;
+          pname = "display";
+          psrc = ./display;
+          pbuildInputs = [
+            (packages."x86_64-linux"."dio" { inherit gcc cflags; })
+            (packages."x86_64-linux"."shift-register" { inherit gcc cflags; })
+          ];
+        };
+
+      packages."x86_64-linux"."prime-tx" =
+        { gcc, cflags }:
+        let
+          pkgs = import nixpkgs { system = "x86_64-linux"; };
+        in mkProgram {
+          pkgs = pkgs;
+          gcc = gcc;
+          cflags = cflags;
+          pname = "prime-tx";
+          psrc = ./prime-tx;
+          pbuildInputs = [
+            (packages."x86_64-linux"."dio" { inherit gcc cflags; })
+            (packages."x86_64-linux"."spi" { inherit gcc cflags; })
+            (packages."x86_64-linux"."shift-register" { inherit gcc cflags; })
+            (packages."x86_64-linux"."rfm" { inherit gcc cflags; })
+            (packages."x86_64-linux"."display" { inherit gcc cflags; })
+          ];
+        };
+
+      packages."x86_64-linux"."radio-rx" =
+        { gcc, cflags }:
+        let
+          pkgs = import nixpkgs { system = "x86_64-linux"; };
+        in mkProgram {
+          pkgs = pkgs;
+          gcc = gcc;
+          cflags = cflags;
+          pname = "radio-rx";
+          psrc = ./radio-rx;
+          pbuildInputs = [
+            (packages."x86_64-linux"."dio" { inherit gcc cflags; })
+            (packages."x86_64-linux"."spi" { inherit gcc cflags; })
+            (packages."x86_64-linux"."shift-register" { inherit gcc cflags; })
+            (packages."x86_64-linux"."rfm" { inherit gcc cflags; })
+            (packages."x86_64-linux"."display" { inherit gcc cflags; })
+          ];
+        };
+
+        /*
       packages."x86_64-linux"."animation-test" =
         let
           pkgs = import nixpkgs { system = "x86_64-linux"; };
@@ -171,138 +280,6 @@
             '';
         };
 
-      packages."x86_64-linux"."sk9822" =
-        { mcu, chip_select, f_cpu }:
-        let
-          pkgs = import nixpkgs { system = "x86_64-linux"; };
-          avr = pkgs.pkgsCross.avr.buildPackages;
-        in pkgs.stdenv.mkDerivation rec {
-          name = "sk9822";
-          src = ./.;
-
-          buildInputs = [
-            (packages."x86_64-linux"."dio" { inherit mcu chip_select f_cpu; })
-          ];
-
-          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
-          INCLUDE_DIRS = pkgs.lib.concatStringsSep " " (map (dir: "-I${dir}") buildInputs);
-          OBJECT_FILES = pkgs.lib.concatStringsSep " " (map (dir: "${dir}/*.o") buildInputs);
-
-          buildPhase = ''
-            ${avr.gcc}/bin/avr-gcc ${CFLAGS} ${INCLUDE_DIRS} -o sk9822.o -c ${src}/sk9822/sk9822.c
-            '';
-          installPhase = ''
-            mkdir $out
-            cp sk9822/sk9822.h sk9822.o $out/
-            '';
-        };
-
-      packages."x86_64-linux"."shift-register" =
-        { mcu, chip_select, f_cpu }:
-        let
-          pkgs = import nixpkgs { system = "x86_64-linux"; };
-          avr = pkgs.pkgsCross.avr.buildPackages;
-        in pkgs.stdenv.mkDerivation rec {
-          name = "shift-register";
-          src = ./.;
-
-          buildInputs = [
-            (packages."x86_64-linux"."dio" { inherit mcu chip_select f_cpu; })
-          ];
-
-          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
-          INCLUDE_DIRS = pkgs.lib.concatStringsSep " " (map (dir: "-I${dir}") buildInputs);
-          OBJECT_FILES = pkgs.lib.concatStringsSep " " (map (dir: "${dir}/*.o") buildInputs);
-
-          buildPhase = ''
-            ${avr.gcc}/bin/avr-gcc ${CFLAGS} ${INCLUDE_DIRS} -o shift_register.o -c ${src}/shift_register/shift_register.c
-            '';
-          installPhase = ''
-            mkdir $out
-            cp shift_register/shift_register.h shift_register.o $out/
-            '';
-        };
-
-      packages."x86_64-linux"."spi" =
-        { mcu, chip_select, f_cpu }:
-        let
-          pkgs = import nixpkgs { system = "x86_64-linux"; };
-          avr = pkgs.pkgsCross.avr.buildPackages;
-        in pkgs.stdenv.mkDerivation rec {
-          name = "spi";
-          src = ./.;
-
-          buildInputs = [
-            (packages."x86_64-linux"."dio" { inherit mcu chip_select f_cpu; })
-          ];
-
-          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
-          INCLUDE_DIRS = pkgs.lib.concatStringsSep " " (map (dir: "-I${dir}") buildInputs);
-          OBJECT_FILES = pkgs.lib.concatStringsSep " " (map (dir: "${dir}/*.o") buildInputs);
-
-          buildPhase = ''
-            ${avr.gcc}/bin/avr-gcc ${CFLAGS} ${INCLUDE_DIRS} -o spi.o -c ${src}/spi/spi.c
-            '';
-          installPhase = ''
-            mkdir $out
-            cp spi/spi.h spi.o $out/
-            '';
-        };
-
-      packages."x86_64-linux"."rfm" =
-        { mcu, chip_select, f_cpu }:
-        let
-          pkgs = import nixpkgs { system = "x86_64-linux"; };
-          avr = pkgs.pkgsCross.avr.buildPackages;
-        in pkgs.stdenv.mkDerivation rec {
-          name = "rfm";
-          src = ./.;
-
-          buildInputs = [
-            (packages."x86_64-linux"."dio" { inherit mcu chip_select f_cpu; })
-            (packages."x86_64-linux"."spi" { inherit mcu chip_select f_cpu; })
-          ];
-
-          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
-          INCLUDE_DIRS = pkgs.lib.concatStringsSep " " (map (dir: "-I${dir}") buildInputs);
-          OBJECT_FILES = pkgs.lib.concatStringsSep " " (map (dir: "${dir}/*.o") buildInputs);
-
-          buildPhase = ''
-            ${avr.gcc}/bin/avr-gcc ${CFLAGS} ${INCLUDE_DIRS} -o rfm.o -c ${src}/rfm69hcw/rfm.c
-            '';
-          installPhase = ''
-            mkdir $out
-            cp rfm69hcw/rfm.h rfm.o $out/
-            '';
-        };
-
-      packages."x86_64-linux"."display" =
-        { mcu, chip_select, f_cpu }:
-        let
-          pkgs = import nixpkgs { system = "x86_64-linux"; };
-          avr = pkgs.pkgsCross.avr.buildPackages;
-        in pkgs.stdenv.mkDerivation rec {
-          name = "display";
-          src = ./.;
-
-          buildInputs = [
-            (packages."x86_64-linux"."dio" { inherit mcu chip_select f_cpu; })
-            (packages."x86_64-linux"."shift-register" { inherit mcu chip_select f_cpu; })
-          ];
-
-          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
-          INCLUDE_DIRS = pkgs.lib.concatStringsSep " " (map (dir: "-I${dir}") buildInputs);
-          OBJECT_FILES = pkgs.lib.concatStringsSep " " (map (dir: "${dir}/*.o") buildInputs);
-
-          buildPhase = ''
-            ${avr.gcc}/bin/avr-gcc ${CFLAGS} ${INCLUDE_DIRS} -o display.o -c ${src}/display/display.c
-            '';
-          installPhase = ''
-            mkdir $out
-            cp display/display.h display.o $out/
-            '';
-        };
-
       packages."x86_64-linux"."flame" =
         { mcu, chip_select, f_cpu }:
         let
@@ -321,7 +298,7 @@
                                                    gcc = "${avr.gcc}/bin/avr-gcc"; })
           ];
 
-          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
+          CFLAGS = mcu_cflags { inherit mcu chip_select f_cpu; };
           INCLUDE_DIRS = pkgs.lib.concatStringsSep " " (map (dir: "-I${dir}") buildInputs);
           OBJECT_FILES = pkgs.lib.concatStringsSep " " (map (dir: "${dir}/*.o") buildInputs);
 
@@ -354,7 +331,7 @@
             (packages."x86_64-linux"."display" { inherit mcu chip_select f_cpu; })
           ];
 
-          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
+          CFLAGS = mcu_cflags { inherit mcu chip_select f_cpu; };
           INCLUDE_DIRS = pkgs.lib.concatStringsSep " " (map (dir: "-I${dir}") buildInputs);
           OBJECT_FILES = pkgs.lib.concatStringsSep " " (map (dir: "${dir}/*.o") buildInputs);
 
@@ -389,7 +366,7 @@
             (packages."x86_64-linux"."display" { inherit mcu chip_select f_cpu; })
           ];
 
-          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
+          CFLAGS = mcu_cflags { inherit mcu chip_select f_cpu; };
           INCLUDE_DIRS = pkgs.lib.concatStringsSep " " (map (dir: "-I${dir}") buildInputs);
           OBJECT_FILES = pkgs.lib.concatStringsSep " " (map (dir: "${dir}/*.o") buildInputs);
 
@@ -422,7 +399,7 @@
             (packages."x86_64-linux"."display" { inherit mcu chip_select f_cpu; })
           ];
 
-          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
+          CFLAGS = mcu_cflags { inherit mcu chip_select f_cpu; };
           INCLUDE_DIRS = pkgs.lib.concatStringsSep " " (map (dir: "-I${dir}") buildInputs);
           OBJECT_FILES = pkgs.lib.concatStringsSep " " (map (dir: "${dir}/*.o") buildInputs);
 
@@ -453,7 +430,7 @@
             (packages."x86_64-linux"."dio" { inherit mcu chip_select f_cpu; })
           ];
 
-          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
+          CFLAGS = mcu_cflags { inherit mcu chip_select f_cpu; };
           INCLUDE_DIRS = pkgs.lib.concatStringsSep " " (map (dir: "-I${dir}") buildInputs);
           OBJECT_FILES = pkgs.lib.concatStringsSep " " (map (dir: "${dir}/*.o") buildInputs);
 
@@ -467,6 +444,7 @@
             cp power-management.elf power-management.hex $out
             '';
         };
+        */
 
       devShell."x86_64-linux" =
         let
diff --git a/shift_register/shift_register.c b/shift-register/shift_register.c
similarity index 100%
rename from shift_register/shift_register.c
rename to shift-register/shift_register.c
diff --git a/shift_register/shift_register.h b/shift-register/shift_register.h
similarity index 100%
rename from shift_register/shift_register.h
rename to shift-register/shift_register.h