Yes it is possible.. One way i can think of is,1. You need two push button, one for increasing & one for decreasing2. In the sketch declare two input variables for the push buttons3. Then assign the input variable to the arduino pins4. Now declare the Constant delay time to increase or decrease4. Now write a code which increases/decreases the delay when button is pressed in the void loop. you can use if statement5. Also store the increased or decreased delay time so that you don't loose your increased or decreased value once you switch offhope this helps you !!!