I am working on a project that requires multiples of the same sensors (up to 20/30) to be daisy chained and connected to an arduino. The sensors I am working with need to be small (maximum of 2 cm wide). I got the project working easily with a one-wire temp sensor, however I need to add a pressure sensor, and as far as I know, there are not any one-wire pressure sensors available. Is this possible for pressure sensors? I know I2C would allow for multiple sensors, however it won't work with multiples of the same sensors (with the same address). Is there any method or pressure sensor that would allow for this to work? I was thinking maybe SPI communication, however, I read that it can only be diasy chained when the master is sending data to the slave and not the other way around.
Pretty much all the I2C devices I have seen have a way to change their address. Whether the devices you are considering can do that, and whether they have enough possible addresses you have to find out.
If the I2C device has at least 1 address line, you can multiplex them, using that line as slave select.
With the line high, the devices will have 1 address, with the line low, they'll have another.
Use a unique pin from the Arduino to each device. Take the pin low to one device, and use the low-pin address to talk to it. The other devices will be looking for the high-pin address, and will not respond.
If the devices are 3.3V and not tolerant of 5V on the address line, then use a discrete resistor per device and pull the line to 3.3V. On the Arduino, leave the pin as an INPUT, and to address a device use digitalWrite to send a 0 to the output first followed by setting the pin to OUTPUT, and then back to INPUT after the transfers is done. That will keep the pin from going to 5V and pulling the address line too high.