Used 2 ea $1.99 HF clamps and scrap steel, quicker to make than time spent (if you have a welder) to order the cam ones on-line.
You could make the parts out of wood also.
Those are slick! I use the malco gauges that sit on top of the lower course, and I have made wood ones too, but they did not hold the plank in place, which is inconvenient when working alone. There are also clips available that can be left in place after nailing the planks up. But I'm impressed with yours.