captcha in alchemy contact form?

[Thomas Gernhardt]

Hi,

I use the magic of alchemy for a contact form as desribed on this site:
http://guides.alchemy-cms.com/3.0/best_practice_create_form.html

Lately I get some spam through this form.

Do you have any advice/experience to include a captcha in the alchemy contact form?

Greetings
Thomas