update README file to set nice donate icon

.github/FUNDING.yml

@@ -0,0 +1,13 @@
+# These are supported funding model platforms
+
+# github: # Replace with up to 4 GitHub Sponsors-enabled usernames e.g., [user1, user2]
+# patreon: # Replace with a single Patreon username
+# open_collective: # Replace with a single Open Collective username
+# ko_fi: # Replace with a single Ko-fi username
+# tidelift: # Replace with a single Tidelift platform-name/package-name e.g., npm/babel
+# community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+# liberapay: # Replace with a single Liberapay username
+# issuehunt: # Replace with a single IssueHunt username
+# otechie: # Replace with a single Otechie username
+# lfx_crowdfunding: # Replace with a single LFX Crowdfunding project-name e.g., cloud-foundry
+custom: ['https://www.paypal.com/donate/?hosted_button_id=9KQNJF4ZW8M5N'] # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']

README.md

@@ -17,6 +17,12 @@ The first batch of 10 pieces is partially built and tested. Further tests will f
 <img src="./Renderings/openDTU.jpeg" width="480">
 </p>
 
+## Donations
+
+As you can see I am in the process of developing a SMT/SMD variant. To support the first 10-25 prototype boards you are welcome to make a donation. This donation should be used to compensate the material costs for components, boards and consumables (soldering paste, etc.). If you want to support the project or future community projects, you are welcome. 
+
+-PayPal: [![Donate with PayPal](https://www.paypalobjects.com/de_DE/DE/i/btn/btn_donate_LG.gif)](https://www.paypal.com/donate/?hosted_button_id=9KQNJF4ZW8M5N)
+
 
 ## Renderings
 
@@ -33,9 +39,24 @@ The first batch of 10 pieces is partially built and tested. Further tests will f
 As described in the previous section, extensions or development stages are maintained in a separate branch. This section is to show exemplarily where the current developments are. Currently a SMD/SMT variant of the board is designed (see picture with the first placement). The SMT will make the board much smaller of course, so it will fit into small cases. All needed components for operation will be on the board. The Programming interface will be connected externally by pin headers, for example. 
 
 <p align="center">
-<img src="./Renderings/openDTU_SMT.jpg" width="480">
+<img src="./Renderings/openDTU_SMT.png" width="480">
 </p>
 
+##  Hardware you need
+
+### ESP32 board
+
+In principle, the hardware recommended [here](https://github.com/tbnobody/OpenDTU) has been used in this project. Unfortunately there are many different variants, especially in the MCU boards, so that you must be very careful that your board is pin-compatible with the following figure. 
+
+<p align="center">
+<img src="./Documentation/NodeMCU-32S-Pinout.jpg" width="480">
+</p>
+
+[figure source](https://i0.wp.com/www.teachmemicro.com/wp-content/uploads/2020/06/NodeMCU-32S-Pinout.jpg?ssl=1)
+
+### Capacitor
+
+As you can see in the graphics above, an electrolytic capacitor is placed between the two boards. This capacitor should be as close as possible to the NRF24L01+ radio board. The size of the capacity should not be larger than 100 uF, typically capacity like 10uF or 22uF are recommended. This also corresponds to the typical capacity in the AP1117 datasheets (keep in mind that the noboard capacity of the ESP32 board has to be added). The voltage stability has to be higher than 3.3V, so all common 5V, 6.3V, 6.5V, 10V, 25V or even 50V are more than enough. 
 
 ## Case