Does someone have an "EXAMPLE CIRCUIT" that is running on MBED that can take 0-30VDC and input into one of the MBED ADC pins (P15-P20) with "ADCinput" example code?

I would like to read 5 "INPUT" voltages from a source 0-30V into the MBED hardware them read the results and output to Pachube :

* HARDWARE - Really looking for "simple input circuit 0-30V" into MBED ADC. (ISOLATED not to blow the MBED would be nice...)

* SOFTWARE - Really looking for simple example code that reads the results of "0-30VDC" circuit that inputs into the P15-P20 MBED ADC.

Thanks!

Jeff

Solar Bank #1	-4.478255	Volts (V)	3 months | 4 days | 24 hours | last hour embed,history,triggers,etc
2	Solar Bank #2	-1.544096	Volts (V)	3 months | 4 days | 24 hours | last hour embed,history,triggers,etc
3	Charge Controller	-3.031838	Volts (V)	3 months | 4 days | 24 hours | last hour embed,history,triggers,etc
4	Battery Bank	-2.742555	Volts (V)	3 months | 4 days | 24 hours | last hour embed,history,triggers,etc
5	Grid Tie Inverter	-1.006855	Volts (V)	3 months | 4 days | 24 hours | last hour embed,history,triggers,etc

I would do a resistor-divider with a Zener rectifier with 5.1V rating in front of mbed.

That way you'll be sure that the Zener eats higher voltages than 5.1V

Regards,
Lerche

and if you need help on the resistor divider too see here

Andy,

I will try it!

Do you have code that I can use to read voltages (0-3.3V) on P15-P20 and and output results linear over 0-40V?

Thanks!  Jeff

Thanks Christian!

I will add 1N5338 Zener 5.1V 5W 5%

Jeff

If you want isolation, you can try an isolation amplifier (i.e. ISO122). The gain for that one is 1 and you need a power supply on both sides. You would still need to use a voltage divider because the amplifier can't take the full 0-30 volts.