P
Phil
- Jan 1, 1970
- 0
I want to implement a keyboard with 7 switches
and need to use an A to D. Seems staightforward
except I need to detect if more than 1 switch is
pressed at the same time. So I will need a ladder
with 0.5,1,2,4,8,16,32 for the resistor values, I plan
to wire 7 resistors in series across each swiches and
feed the A to D from RX/R1 junction.
Has anyone done this before and any idea what values
to use for RX and RY with R1 = 500, R2 = 1K ...R7
= 32K ?
VCC--RX--R1--R2 --R3--R4--R5--R6--R7--RY --VSS
Phil
and need to use an A to D. Seems staightforward
except I need to detect if more than 1 switch is
pressed at the same time. So I will need a ladder
with 0.5,1,2,4,8,16,32 for the resistor values, I plan
to wire 7 resistors in series across each swiches and
feed the A to D from RX/R1 junction.
Has anyone done this before and any idea what values
to use for RX and RY with R1 = 500, R2 = 1K ...R7
= 32K ?
VCC--RX--R1--R2 --R3--R4--R5--R6--R7--RY --VSS
Phil