I am trying to build a standing desk but I want it to be wireless (aka - no electricity needed).
My idea is:
have 4 hydraulic pistons that extend (from 60 cm (25in) to 120 cm (50in)).
They will be extended by a pedal or a pump (like a bike pump) by a few pushes (manual work).
The initial lifting weight shouldn't be much, around 20-30 kg (44-66 lbs) just for the desk and some books/laptops
Then, the desk should be able to withstand some weight, maybe 40kg (88 lbs) without the pistons retracting (similar to how gaming chairs are).
Then, there should be a second pedal, which would release the pressure in the pistons causing them to retract and hence, lower the table.
I understand the theory, but it's hard for me to work out how I can build this myself. I need guidance on what kind of items (pistons, pedals) I should be looking to get and where I can get them from.
It's also very important to know that the budget here is limited, if the system would cost over 400€ to manufacture, I would rather buy it.
Thanks a lot for the help!