diff --git a/sf-writer/sf_h5_writer.cpp b/sf-writer/sf_h5_writer.cpp
index 7c49d8d..1251e4d 100644
--- a/sf-writer/sf_h5_writer.cpp
+++ b/sf-writer/sf_h5_writer.cpp
@@ -42,7 +42,7 @@ int main (int argc, char *argv[])
     auto image_buffer = make_unique<uint16_t[]>(n_modules*512*1024);
 
     uint32_t all_modules_ready = 0;
-    for (size_t i=0; i<32; i++) {
+    for (size_t i=0; i<n_modules; i++) {
         all_modules_ready |= 1 << i;
     }
 
@@ -51,6 +51,8 @@ int main (int argc, char *argv[])
     auto ctx = zmq_ctx_new();
     zmq_ctx_set (ctx, ZMQ_IO_THREADS, 16);
 
+    vector<thread> threads;
+
     auto read_thread = [&](int module_id) {
         auto socket = zmq_socket(ctx, ZMQ_PULL);
 
@@ -98,6 +100,10 @@ int main (int argc, char *argv[])
         }
     };
 
+    for (size_t i=0; i<n_modules; i++) {
+        thread test(read_thread, i);
+    }
+
     int i_write = 0;
     size_t total_ms = 0;
     size_t max_ms = 0;