Automation Engineering student, with experience in programming microcontrollers for Sumo Robot Competitions
I have my own Arduino Mega, arduino uno or Arduino Leonardo that i can use, and i can have the basic working of the program ready in less than a day. This includes measuring the time between pressing button 1 and pressing button 2, and setting a digital output high for a hardcoded amount of time. that can be easily changed into an amount of time that can be set from any kind of interface.
The rest of the time is allocated to get a shield similar to yours shipped to me (i could probably source one locally, but i am not 100% sure) and to begin final user interface tweaks. Clarifications to the specifications are also needed:
What will this product be used like? A quiz game? a Tachometer?
Are the buttons in question actual buttons, or are they external devices that supply a TTL signal? Do the buttons generate particularly noisy signals? Do they need software debouncing, or they need hardware debouncing?
What is the estimated time range between pressing the first and second button?
How accurate are the measurements supposed to be? Is this device supposed to be certified by any existing standards?
Depending on the specifics, this project can be done in 2 days, or it could take up to a week of testing, emailing, and clarifying specifications.