I would like to know what is the best way of sending a signal to a smartphone, would it be via Bluetooth? The range needed would not be more than 2 meters, and the device sending the signal should be a very simple device with e.g. two buttons, each sending a different signal or ID. The logic of what needs to happen once the signal is received would be embedded in the software running on the smartphone. Also which microchip would be needed and what type of pricing am I looking at(looking for a fairly cheap cost)? The device should be as small as possible e.g. matchbox size and would need to be able to work under rough conditions, but I am assuming that will just depend on the type of mold/casing the chip and buttons will be built into. I am happy to only support IOS and Android phones released in the last +-12 months and any going forward.
Hope that provides enough information, and sorry for the limited electronic based technical info, but I do not know a lot about electronics and sit more on the software side of things.
Thanks in advance.