Re: [Repeater-Builder] Re: Monitoring Positive Ground 48 to negative Ground 0-5

2010-01-31 Thread Mike Morris
Does your digi have a serial port? Can you send and receive data in and out? Maybe this might work... http://www.linuxtoys.org/dvm/dvm.html or this... http://www.viddata.com/dvm_hardware.htm or this... http://www.rs232pro.com/rs232/rs232_dvm_kit.htm Mike WA6ILQ At 02:42 PM 01/30/10, you

Re: [Repeater-Builder] Re: Monitoring Positive Ground 48 to negative Ground 0-5

2010-01-31 Thread Joe
If you made a simple voltage divider that would give you around 12VDc from the 148VDC power plant you could use a circuit like this to watch the voltage change: http://dev.emcelettronica.com/howto-monitor-lead-acid-batteries-charge The LM3914 would give you high/low outputs at the LED lights

[Repeater-Builder] Re: Monitoring Positive Ground 48 to negative Ground 0-5

2010-01-30 Thread skipp025
Chuck Kimball n0...@... wrote: Speaking of monitoring Anyone have an easy way of converting a Positive Ground 48 to 72 volt system to a Negative Ground 0-5V for monitoring? Do you want the voltage to vary with change in the 48 to 72 volt dc supply? s.

Re: [Repeater-Builder] Re: Monitoring Positive Ground 48 to negative Ground 0-5

2010-01-30 Thread Chuck Kimball
Yes, trying to monitor the local -48 Power system, and solar charging system with my APRS digi +12VDC that accepts 0-5VDC input. Chuck skipp025 wrote: Chuck Kimball n0...@... wrote: Speaking of monitoring Anyone have an easy way of converting a Positive Ground 48 to 72 volt system to a

Re: [Repeater-Builder] Re: Monitoring Positive Ground 48 to negative Ground 0-5

2010-01-30 Thread Ken Arck
At 02:42 PM 1/30/2010, Chuck Kimball wrote: Yes, trying to monitor the local -48 Power system, and solar charging system with my APRS digi +12VDC that accepts 0-5VDC input. You need a DC-DC converter. This should help you get started http://www.maxim-ic.com/app-notes/index.mvp/id/2031

Re: [Repeater-Builder] Re: Monitoring Positive Ground 48 to negative Ground 0-5

2010-01-30 Thread Ed Yoho
Chuck Kimball wrote: Yes, trying to monitor the local -48 Power system, and solar charging system with my APRS digi +12VDC that accepts 0-5VDC input. Chuck Probably the simplest would be to use an opamp as a X 0.1 inverting amplifier: 10K

Re: [Repeater-Builder] Re: Monitoring Positive Ground 48 to negative Ground 0-5

2010-01-30 Thread DCFluX
How about a Optoisolator? Like a 4N25, I'd use a 47K resistor on the LED side and play with the resistor value on either side to get the readings right, but its what they do in switch mode supplies to make the DC side talk to the AC control circuits.

[Repeater-Builder] Re: Monitoring Positive Ground 48 to negative Ground 0-5

2010-01-30 Thread skipp025
Chuck Kimball n0...@... wrote: Yes, trying to monitor the local -48 Power system, and solar charging system with my APRS digi +12VDC that accepts 0-5VDC input. Chuck The next part is how much resolution and accuracy do you want? There are a number of ways to fudge fixed step reporting