I have gone beck and looked at a long running project (I keep getting side tracked with work and other things).
In an ideal world I would need 11 M/ohms, however I think the 1M/ohm will be fine. The current prototype uses a rotary switch and 11, 100k/ohm resistors.
The application will be in an audio detector circuit (https://learn.sparkfun.com/tutorials/sound-detector-hookup-guide will replace r3 and r17).
I found this: http://www.farnell.com/datasheets/1934966.pdf?_ga=2.130267023.1813097283.1540600845-2089259871.1533396072 which I hope will work just fine.
Another option would be have a resistor ladder controlled by a Picaxe via some from of switch (opto, bilateral or something else).
I am also leaning towards using i2c if using a digital pot or port expander (to control switches if needs be), its normally fairly easy to use, and will keep pins spare. I also intend to use another smaller digital pot (5k) for control of a another sensor which can go on the same bus.
Currently the bread board version uses a 20X2, but will need to move to at least a 28X2, not just for pin count, but for programme space as well. hardware serial is being used for communicating with the display.
Is there anything I obvious I have overlooked? Is there a better option for a digital pot? Will the picaxe be able to deal with the i2c of the digital pot? Any suggestions on the smaller 5k pot? I've not even started looking for one yet.
In an ideal world I would need 11 M/ohms, however I think the 1M/ohm will be fine. The current prototype uses a rotary switch and 11, 100k/ohm resistors.
The application will be in an audio detector circuit (https://learn.sparkfun.com/tutorials/sound-detector-hookup-guide will replace r3 and r17).
I found this: http://www.farnell.com/datasheets/1934966.pdf?_ga=2.130267023.1813097283.1540600845-2089259871.1533396072 which I hope will work just fine.
Another option would be have a resistor ladder controlled by a Picaxe via some from of switch (opto, bilateral or something else).
I am also leaning towards using i2c if using a digital pot or port expander (to control switches if needs be), its normally fairly easy to use, and will keep pins spare. I also intend to use another smaller digital pot (5k) for control of a another sensor which can go on the same bus.
Currently the bread board version uses a 20X2, but will need to move to at least a 28X2, not just for pin count, but for programme space as well. hardware serial is being used for communicating with the display.
Is there anything I obvious I have overlooked? Is there a better option for a digital pot? Will the picaxe be able to deal with the i2c of the digital pot? Any suggestions on the smaller 5k pot? I've not even started looking for one yet.