diff --git a/lib/onoffsim/Readme.md b/lib/onoffsim/Readme.md
index e69de29..1825111 100644
--- a/lib/onoffsim/Readme.md
+++ b/lib/onoffsim/Readme.md
@@ -0,0 +1,21 @@
+
+
+## onoffsim
+Object representing a fake onoff Gpio class
+
+**Kind**: global constant
+
+
+### onoffsim.Gpio(no, dir, additional) ⇒ object
+Gpio() -
+Create's a Gpio class in the case of running on a dev machine
+
+**Kind**: static method of [onoffsim
](#onoffsim)
+**Returns**: object
- Fake Gpio object
+
+| Param | Type | Description |
+| --- | --- | --- |
+| no | integer
| Number of the GPIO pin |
+| dir | string
| Dirction of the pin, 'input' or 'output' |
+| additional | string
| Additional instructions for the GPIO pin, for 'input' type |
+
diff --git a/lib/onoffsim/index.js b/lib/onoffsim/index.js
index b45bb01..cd3ca77 100644
--- a/lib/onoffsim/index.js
+++ b/lib/onoffsim/index.js
@@ -1,6 +1,16 @@
'use strict'
+/** Object representing a fake onoff Gpio class */
const onoffsim = {
+ /**
+ * Gpio() -
+ * Returns a Gpio class in the case of running on a dev machine
+ *
+ * @param {integer} no Number of the GPIO pin
+ * @param {string} dir Dirction of the pin, 'input' or 'output'
+ * @param {string} additional Additional instructions for the GPIO pin, for 'input' type
+ * @returns {object} Fake Gpio object
+ */
Gpio : function (no, dir = 'in', additional = 'none') {
//
return {