basic ECG info

en/ecg/_index.md

-# ECG
+# How to use the ECG
 
+Here's some basic info on how to use the ECG functionality of your card10
+
+## Finger ECG
+
+![Top View Harmony Board](top_1-4.jpg "Finger ECG and Pulse Oxymeter")
+
+Your card10 comes with a number of fun things to play with
+
+  - 1   : Contact,  negative ECG electrode 
+  - 2   : Pluse oxymeter (can [potentially, if at some point supported by software] measure pulse and blood oxygen levels using an optical sensor)
+  - 3   : Contact,  negative ECG electrode (again)
+  - 4   : Screw (also works as a negative electrode, see [8])
+
+
+![Bottom View - ](bottom_5-6.jpg "COM for Bias and positive electrode for finger ECG")
+
+  - 5 : COM (for bias)
+  - 6 : Contact, positive ECG electrode 
+
+![Side View Details](side_front_7-8.jpg "Pin and isolation")
+
+  - 7 : Pin for soldering/stitching an alternative electrode, if you don't want to use (6)
+  - 8 : Plastic distancer, works as an isolation (see [4])
+
+## USB ECG
+
+  - see [ECG Kit Assembly](../ecg_kit_assembly/) on how to solder your ECG cable
+  -  NB: it DOES matter how you connect the kit via USB. if you get a lot of noise, try to turn the connection
+
+
+Have fun experimenting with the ECG.

en/gettingstarted.md

@@ -71,6 +71,11 @@ Initially, BLE is disabled for privacy reasons. If you want to use it, you have
   * Via the menu: Select the ble.py from the menu and press the SELECT button to enable BLE. The board will restart with activated BLE. Deactivation can be done via the same app.
   * Manually: Start the card10 in _USB storage mode_ and add a file `ble.txt` with (exactly) the content `active=true` then reset the board.
  
+### basic ECG howto
+Have a look at [how to use the ECG](../ecg/).
+
+For better results use [USB-C electrodes](../ecg_kit_assembly/)
+
 
 ## Next
 Now it is time to start playing with the card10, writing your own micropython code!