I've had flakey 5V power in my greenhouse for some time now. I've tried various wall-warts of differing ampage but no go. Finally I pulled power directly from the computer PSU this helped but it was still slightly below 5V (4.86V).
So i built a 12V to 5V 3A convertor using LM7805 regulators in parallel. Circuit diagram below.
Big thank you to Colin @ g1gsw with the help designing this.
Now, it is much better with 5.28V in the greenhouse (measured by a ds2438 Smart Battery Monitor).
Circuit diagram:
ascii image
0010101000011111101001101010000010011000
1110101110110101011011111010010010001011
0001011100011101111001010011010010111110
0000010111101001100000110011101100001000
0011000000111010001111111000100110000001
1010110110000000000001011001000110001010
0101100010101100000100000010100100010101
0001011001011101100011000101110111101110
0110010100110100111101110100110011111101
0010111100110011010010110010101111011011
0100000000001001001011000010110100101001
1101000111100000110111011100110111000010
1111110001111111101101001010000111101100
0010110000100000111011000000101100010110
0101111000011100111010000000011111101111
0010010011110010011101001000110101000101
0000000001000100001111111100111010001111
Saturday 22 January 2011
1-wire PSU
Tags:
1-wire,
ds2438,
lm7805,
psu,
weather station
Friday 14 January 2011
New soil temperature sensors
Due to the very cold weather we had in December, -15C and below, my soil temperature sensors didn't hold up.
The sealant i used (brown frame sealant) deteriorated in cold - which is bad for anyone using it to keep their windows in !
So now i have set the sensors in the same 7mm dia. copper pipe, but only used 50mm long pieces. Hopefully the HMA (Hot melt adhesive) - more commony know as hot glue gun stuff - will keep the water out.
Initial testing showed the sensors reading 35C and 37C while the glue cooled. :)
Now i have to come up with a method to connect the sensors back to the cable i removed them from - last time it was all one piece.
The sealant i used (brown frame sealant) deteriorated in cold - which is bad for anyone using it to keep their windows in !
So now i have set the sensors in the same 7mm dia. copper pipe, but only used 50mm long pieces. Hopefully the HMA (Hot melt adhesive) - more commony know as hot glue gun stuff - will keep the water out.
Initial testing showed the sensors reading 35C and 37C while the glue cooled. :)
Now i have to come up with a method to connect the sensors back to the cable i removed them from - last time it was all one piece.
Tags:
ds1820
Thursday 6 January 2011
owfs errors : BUS_select_subbranch
I've been getting errors on owfs for some time now, but after reading the doco and discovering the error stats, i thought i would look into it more.
$ grep -v " 0" /var/1wire/bus.0/interface/statistics/*error*
/var/1wire/bus.0/interface/statistics/errors: 359
/var/1wire/bus.0/interface/statistics/select_errors: 359
turning on debug on owfs with "--error_print 1 --error_level 5"
Then you get to see things like this:
Jan 6 14:00:37 ubuntu OWFS[32423]: DEBUG: ow_select.c:BUS_select_subbranch(178) Selecting subbranch 1F 8F 67 05 00 00 00 B6
Jan 6 14:00:37 ubuntu OWFS[32423]: DEBUG: ow_bus_data.c:BUS_send_data(38) Response doesn't match data sent
but this doesnt tell me what branch is at fault main/aux
So i edited the following file in the source code and recompiled
/var/1wire/bus.0/interface/statistics/errors: 359
/var/1wire/bus.0/interface/statistics/select_errors: 359
turning on debug on owfs with "--error_print 1 --error_level 5"
Then you get to see things like this:
Jan 6 14:00:37 ubuntu OWFS[32423]: DEBUG: ow_bus_data.c:BUS_send_data(38) Response doesn't match data sent
but this doesnt tell me what branch is at fault main/aux
So i edited the following file in the source code and recompiled
Wednesday 5 January 2011
WeatherSnoop to mySQL
I've placed the code for the script i wrote for a friend (g1gsw) on googlecode in case anyone else wants a copy.
It reads the WeatherSnoop (v2) XML and places it into a mySQL database.
https://code.google.com/p/weathersnoop-to-mysql/
It reads the WeatherSnoop (v2) XML and places it into a mySQL database.
https://code.google.com/p/weathersnoop-to-mysql/
Tags:
mysql,
weather station,
weathersnoop
1-wire, long runs and owfs
My 1-wire MicroLAN has a long run using BT cable (the stuff that comes into your house from the pole outside) it's not the most capable and CAT5 is better if you can use it, but mine runs through my flowerbeds into my greehouse, so it needed to be semi-amoured.
Long runs need slightly different 1-wire slew rates or you get lots of errors and devices drop off your LAN :(
Maxim Application Note 148 states:
Testing with long and short bus lines has shown that the optimum timings for all networks are as follows:
Pulldown Slew Rate: 1.37V/μs
Write One Low Time: 11μs
Data Sample Offset/Recovery: 10μs
So with owfs how do you do that with your Maxim USB dongle...?
Long runs need slightly different 1-wire slew rates or you get lots of errors and devices drop off your LAN :(
Maxim Application Note 148 states:
Testing with long and short bus lines has shown that the optimum timings for all networks are as follows:
Pulldown Slew Rate: 1.37V/μs
Write One Low Time: 11μs
Data Sample Offset/Recovery: 10μs
So with owfs how do you do that with your Maxim USB dongle...?
Saturday 1 January 2011
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