Thanks for submitting this and sorry it took me so long to get around to looking at it.
A couple changes I would like to see before the merge:
Your design files should be incorporated into the repo, rather than a text file with a url pointing at them. Remember, your name will be associated with this material via this pull request so you are guaranteed credit for your work. Put them into the /resources folder in place of the text file you have now. Make sure the file name has no spaces. It also should not contain a date - that is what revision control is for! To link to it in the manual, use a markdown style relative link, e.g. cartoon. Look at the raw version of this comment to see how I did that.
The text about the led should be removed from the opening paragraph of the manual. Although its a nice addition, its not the main point of the project. For instance, I have a photodiode amplifier in the repo that I don't mention in the opening paragraph. You can feel free to move this text to a main heading right before the construction section of the manual.
Thanks for submitting this and sorry it took me so long to get around to looking at it.
A couple changes I would like to see before the merge: