Mr RB
Well-Known Member
Hi, I've been working on a verbal voltage alarm using a TalkBot PIC controller. This has a PIC 16F628, 20MHz resonator and a low power low dropout +5v regulator and I am using the comparators to measure an analog voltage so the alarm sounds if the voltage is over/under X volts.
The idea is that it can be used for any basic alarm condition over/under voltage or temperature or light level etc etc and the TalkBot speaks a verbal alarm message. This may be of use for visually impaired and/or elderly people.
The power source will be 4 cells (AA or AAA) or maybe a 9v battery. I'm trying to get the PIC power consumption to a minimum. The other hardware is good, the +5v regulator, audio amp and eeproms only use a handful of uA when not playing the sound alarm.
Does anyone have any suggestions about how to get the PIC current down to the minimum? It only needs to check the alarm about twice a second as it is for slow changing signals like temperature or battery voltage. I have never done a very low power project using a PIC and comparators, so I would appreciate any tips re whether its worth turning the comps and vref OFF while in sleep mode, vs leaving them on so they are stable and not needing to be running for as long. Likewise i'm not sure about the other peripherals, timers etc if it is worth messing with them or even if an external resistor vref will use less power than the internal one etc etc.
Any tips are welcomed for leaving the PIC in a very low power sleep for 0.5 seconds, then minimising the total time/current needed to wake up and just check one comparator to test 1 voltage.
The idea is that it can be used for any basic alarm condition over/under voltage or temperature or light level etc etc and the TalkBot speaks a verbal alarm message. This may be of use for visually impaired and/or elderly people.
The power source will be 4 cells (AA or AAA) or maybe a 9v battery. I'm trying to get the PIC power consumption to a minimum. The other hardware is good, the +5v regulator, audio amp and eeproms only use a handful of uA when not playing the sound alarm.
Does anyone have any suggestions about how to get the PIC current down to the minimum? It only needs to check the alarm about twice a second as it is for slow changing signals like temperature or battery voltage. I have never done a very low power project using a PIC and comparators, so I would appreciate any tips re whether its worth turning the comps and vref OFF while in sleep mode, vs leaving them on so they are stable and not needing to be running for as long. Likewise i'm not sure about the other peripherals, timers etc if it is worth messing with them or even if an external resistor vref will use less power than the internal one etc etc.
Any tips are welcomed for leaving the PIC in a very low power sleep for 0.5 seconds, then minimising the total time/current needed to wake up and just check one comparator to test 1 voltage.