A former Rickmansworth School pupil took his own life using a concoction of chemicals that filled his tent with lethal fumes, an inquest heard.
Andrew Kirkman had struggled with depression in the lead up to his body being found on a common in Oxford in December.
A coroner was told today how Mr Kirkman, who grew in Northwood, hid his depression from his family as he did not want them to worry.
Speaking after the inquest, his mother, Wendy Kirkman, said: "Andrew was an amazing young man. He spent an inordinate amount of time assisting others and was a force for good in every community he was involved in.
"The attendance at his funeral of over 250 souls is a testament to how many lives he touched in his 20 years among us."
The inquest, at Oxford Coroner’s Court, heard the straight-A student, who was studying at Oxford University, had purchased chemicals over the internet in on November 28 and 29.
The 20-year-old Physics and Philosophy undergraduate then put up signs warning passers-by not to enter the toxic tent.
Mr Kirkman's body was found by a father who was walking with his son and his son's friend in the Oxford common at about 12.20pm on December 8.
A statement read out at the inquest revealed how, when Crispin Maceijewski approached the lone tent, he could smell rotten eggs, which is indicative of hydrogen sulfide.
Pieces of paper positioned around the tent also warned people of the toxic gasses that were contained within, informing them not to enter without protective clothing.
Darren Salter, Oxfordshire coroner, said that the act itself took "considerable planning" and that Mr Kirkman had a history of suicidal thoughts and depression.
He added: "I am satisfied that, sadly, Andrew did intend to take his own life."
A verdict of suicide was recorded.