Water Meter Power?

After a few days of running the water meter has worked well. Thoughts have turned to formalizing it with a proper PCB, mounting and how to power it. It currently has a 3000mAh battery and a solar panel for a little help during the day. This ran the Arduino Nano and xbee for 2.5 days before running flat. I found out today when removing the meter (it was flat) the solar panel on an overcast day can run the current setup no problem.  By extending the battery life I can be sure that even if there is extremely bad weather for a few days the meter will not have any outages. So far I have 3 thoughts on reducing power usage:

  • Put the xbee to sleep with a Pin from the nano to save some power in between the minutely broadcast.
  • Build a custom arduino into the PCB to ditch all the extra component drain that arduinos come with.
  • Put the arduino asleep with the Jeelib library in between sensor reads

One other problem is the location of the power meter, it is in a very shady spot, more especially when the trees around it get their leaves back from winter. This brings up another option, I could run a wire from the house to power it. What to do? I’m not sure which way I’ll turn yet. In the meantime I will hook up the meter to the multimeter and see how much current it is actually drawing. I’ll be able to actually see how effective the above points will be at reducing power usage.

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Water Metering?


I’ve had ideas on monitoring the Houses water usage for awhile. The method I was thinking, which was severing the mains and putting a flow meter in between, didn’t sound like the best of ideas. The flow meters I have around don’t really look up to snuff for something as hardcore as monitoring the water mains. Per tap is another thing though. I think they would be great at this. It was then when I was reading through some hackaday.com articles when I came across HackersBench project to monitor is own water usage. He had the fantastic idea of monitoring the magnet that spins around inside the mains water metre with a magnetometer! Surely not I thought, can this really be detected? I wasn’t sure if the magnetometer would be able to get close enough to the magnet to pick up anything. It was damn well worth trying out though. I breadboarded up an Arduino nano, A LCD , a battery pack and a MAX3110 magnetometer.20140913_151630

I banged out some quick code to show the readings on the X,Y and Z axis and went out to test. I ended up having to dig out my meter a bit to get to it better. Amazing how much crud builds up in there. I remembered cleaning it out 3-4 years ago.20140913_151641

I turned a tap on and left it running and ran back to the meter. Holding the sensor in place I fired up the Arduino and…. BINGO! It was easy to see the Sine wave of results appearing on the LCD. Up Down Up Down. This was excellent. I was quite excited. I took the contraption I had built inside and over the next few days have been coding and testing a more permanent solution. I added an XBee to the solutions and updated MotherHubs code to accept the new sensors. The code so far seems robust. Its been running most of  the day with no problems. I made a few changes including calibrating how many of the rotations of the magnet meter it takes for a litre of water to be measured. Hopefully its pretty dead on now. the mains meter is a Davis Shephard type. No model number that I can see and I couldn’t find any Specifications on the net. If anybody else is looking I have it as 57.1428 millilitres per turn of the magnet.

Here are some graphs from Xively.com. Not the best but until I get my own web front end up they tide me over 🙂 These are based over 12 Hours.


Water Usage. Litres per minute

Water Usage. Litres per Hour

Water Usage. Litres per Day

This has completely side tracked me from the PowerArdy project but I have enjoyed it thoroughly. Need to get to work on designing a PCB for it! I have the breadboarded unit inside a lunch box by the meter at the moment. Not sure how long the battery can run it as yet. I’ll have to add battery monitoring next 🙂

Posted in Arduino, Electronics, SensorNet | Tagged , , , , | 3 Comments

PowerArdy Arrives!

2014-09-14 18.59.32





The PCBs arrived from DirtyPCBs.com! They came much faster than the first lot I ordered. I wasn’t expecting them in the 2 weeks they took to come, nevertheless enough of the other parts I needed had come that I could put the main bits together!



That very night after work I busily got the parts together to solder up…


Tada! Mostly completed. its still missing the 3 terminals for the doorbell, motion and light detection. They haven’t arrived yet. I made a mistake there and used the wrong spaced terminals. So many parts to choose from in EaglePCB!


2014-09-14 18.59.32

I fitted it into an arduino UNO and quickly got to some testing. Alas, all my results were coming in at zero, something was up! I was out of time and didnt get back to it for another 2 weeks. Seems my code was just a bit off and the library I was using from openenergymonitor.org needed some slight changes. I fixed all that up and I had results! Well 3 results out of the 5. The 9V AC jack was wired wrong but easy to fix with a small piece of wire. The Pink 3.5mm jack above was the other problem. I tested components over and over ruling them out until finally i was following a trace and found this (See red arrow below)

IMG_20140909_231356 (1)


A manufacturing Defect! I could not believe it! I checked the other 9 boards I got from DirtyPCBs and all of them were fine. Just the lucky one I had chosen had the flaw. Ha! This should be easy to fix with some careful scratching of the PCB. I’ve learnt to check over the PCB first before putting the boards together now. Lesson learnt. Not far away now from having very decent power monitoring!

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Introducing PowerArdy!

My second PCB Ever has been sent of for fabrication! I’ve been lazy and haven’t posted my first Circuit Board Ever yet. This will replace my Current Cost Envi unit which has been beavering away for a few years now with 2 current Sensors. Since adding Solar to the house 2 isn’t enough. I have one Sensor on the total house power circuit (Mains) and the other around the Heating Circuit which services the Hot water Cylinder and the Heatpump. I pull 3 totals out of this by subtracting the Heat circuit off the total power circuit to give me the leftover which is powerpoints and Lights. There has been some anomalies with this which to be honest I haven’t looked into my code to see if its a bug there or something else. The new PowerArdy has 4 Current sensors on it! They will monitor:

  • Lights and Power
  • Heater Circuit
  • Solar Production
  • Total Power

This will hopefully fix the anomaly with my data. The other problem I have with the old setup is when I have a surplus of power from the solar and it starts exporting to the grid it appears as power consumption on my graphs! No good at all. I’ve also gone pro by adding a 9V AC-AC Powersupply that will monitor the line voltage to calculate power factor. This in turn lets you calculate real power value properly. Also in the mix, as this unit will be by the Front door, I’ve added a PIR sensor for motion detection, a TMP36 temperature sensor, a light sensor and a button. The button is for a coming Doorbell button. Which as it happens is how I started playing with Arduino stuff in the first place! I just wanted a doorbell! I have a lot of trouble hearing anybody at the door which I plan on fixing with a very loud old school Siren I have around here somewhere. Awesome sauce…… once its setup 🙂 Also included is a Xbee to shoot all the data through to motherhub.

Here is the PCB layout of the new board



I hope its all correct! Will be a 4-8 weeks before I see the boards yet so I have some time to wait. In the meantime I’ve ordered all the other parts I don’t have here. Version 2 of this will probably have a arduino included in the design instead of being an Arduino shield as it is now.

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Reading a Serial output from Arduino with Python V1

This is my first try at Python. It reads the Serial Output from Serial 3 on MotherHub. I had some problems with it randomly throwing exceptions, I seemed to have solved that with some If statements that count the amount of variables. The next 24 hours will be the big test as I just set the script up as a service for uninterrupted SQL insertions 🙂 I’m sure this script will expand over the coming months.

import serial
import MySQLdb
import datetime
from time import sleep
ser = serial.Serial('/dev/ttyAMA0', 9600, timeout=0) # This is using the serial GPIO pins on the Raspberry Pi, Pins 14 and 15
conn = MySQLdb.connect( host='Your MySQL server IP', db='SensorDB', user='SensorDBUser', passwd='SensorDBPass' ) #Change these to suit
cursor = conn.cursor()
count = 0
while True:
 data = ser.read(9999).strip("\r\n")
 parsed = data.split(",")
 if len(data) >= 54:
 print 'Serial Packet Length:', len(data)
 print 'Got:', data
 print 'parsed:', parsed
 templist = data.split(',')
 print 'Length:', len(templist)
# print templist
 if len(templist) < 12: #If there arent 12 items parsed from the Arduino output string then somethings not right, Go to Jail. Do not pass Go
 print 'templist[0]:', templist[0]
 print 'templist[1]:', templist[1]
 print 'templist[2]:', templist[2]
 print 'templist[3]:', templist[3]
 print 'templist[4]:', templist[4]
 print 'templist[5]:', templist[5]
 print 'templist[6]:', templist[6]
 print 'templist[7]:', templist[7]
 print 'templist[8]:', templist[8]
 print 'templist[9]:', templist[9]
 print 'templist[10]:', templist[10]
 print 'templist[11]:', templist[11]
 # Prepare SQL query to INSERT a record into the database.
 sql = "INSERT INTO tblSensorData(fldCommsMotion, fldCommsTemp, fldCommsBarometer, fldCommsHumidity, fldCommsLux, fldXbee1Temp, fldXbee1Volt, fldXbee1Battery, fldXbee1SolarV, fldTotalPowerUse, fl dHeatuse, fldLightPower) \
 VALUES ('%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s' )" % \
 (templist[0], templist[1], templist[2], templist[3], templist[4], templist[5], templist[6], templist[7], templist[8], templist[9], templist[10], templist[11])
 print"sql ready for execution"
  # Execute the SQL command
 print"SQL Injected!"
 count = count + 1
 print 'SQL Update Count:', count #This is just so I can easily see how many updates have processed before an exception
# Commit your changes in the database
print 'not blocked'

MySQL Data is logging! This is massive motivation to get more sensors online. Even though I don’t have a frontend yet I know the data is there to play with.



In my travels with PHPMyAdmin I just noticed it has some basic graphing function! Amazing! When did they add that? Now I’ve noticed a problem with the power records


PHPMyADmin graphI have 2 sensors monitoring Power. One on the mains for the entire house and one on the Heating Circuit which does the hot water cylinder at the Heat pump. To calculate the lights and power circuit I simply minus the Heating circuit off the total power circuit. The graph however is showing that every time the heater comes on the power use for the house drops considerably. This is not correct. The difference between the Heating consumption and the total should always be consistent. I’m tempted to look further into this but at the same time I could put those efforts into completing my new energy monitor. I’ll think on it awhile and see if something comes to me


Posted in Arduino, Computing, Electronics, MySQL, phpMyAdmin, Python, Raspberry Pi, SensorNet | Tagged , , , , , | Leave a comment

Run Python code as a service

Testing of my python script that reads the serial output from MotherHub seems stable enough to run fulltime now. What I’ve found is though that everytime I turn my PC off my SSH session will time out and kill the python script from running. What I need is a way to run it all the time and auto start it after a reboot. Peiter Vanos has just the thing! I am reposting here for my own reference later. You can find the original code at http://www.pietervanos.net

1. place your python script in the following folder: /usr/local/sbin/ (This can be anywhere you like)
2. create a new file in /etc/init.d/ in this case it will be example, so sudo nano /etc/init.d/example
3. Use the following code for the example file

#! /bin/sh
# /etc/init.d/example
case "$1" in
echo "Starting example"
# run application you want to start
python /usr/local/sbin/example.py &
echo "Stopping example"
# kill application you want to stop
killall python
echo "Usage: /etc/init.d/example{start|stop}"
exit 1
exit 0

4. give the file execute rights, sudo chmod 755 example
5. now execute: sudo update-rc.d example defaults

When you reboot raspbian it should automatically start the python script, else try service example start and service example stop


This worked like a charm for me. I could see SQL entries within a minute! Now to see if it can run 24/7 with no problems

Posted in Linux, Python, Raspberry Pi, SensorNet | Tagged , , | 1 Comment

Home SensorNet Overview

I have an ongoing project that involves my house and sensors. I’ve been working on and off on this as enthusiasm warrants but failing to actually post anything about it on dangertech. So this is it, I’m going to give a general overview interspersed with pictures as a starting point and see what happens. I plan on sensoring the shit out of my home. Sensors in every room that include at a bare minimum Temperature, motion and light levels. There are many more add-ons I want to achieve including Oven temperatures, Freezer temp, Water flow etc etc etc etc. I love stats and cant get enough.

SensorNet aka. Motherhub is an Arduino Mega2560 that runs the network of Xbees and arduinos around the house which so far consists of:

  • Arduino Mega2560 as MotherHub
  • Arduino UNO as data parser from power meter
  • Xbee Co-Ordinator as base unit for Xbee network
  • Outdoor Xbee Temp Sensor that also reports on battery level and solar Voltage
  • CurrentCost Energy Meter measuirng the mains power and outputting to above UNO

Ha. After listing that it doesn’t look like much for the hours of work I’ve poured in. There are also a few projects not completed enough that they are included in the above list:

Arduino UNO Weather unit

  • Wind Speed
  • Wind Direction
  • Rain Gauge
  • Temperature

This one is a little cheaty as it incorporates some Sparkfun parts. The wind and rain sensor are here and a convenient Ardy shield with some nice code on Github are here. To finish this I need to:

  • Xbee hooked up and coded
  • Power requirements calculated to run from solar and a battery
  • Housing designed and printed/built

Arduino House Foyer Sensor Node 

This is all Bread boarded up and tested. It includes:

  • 2 temperature sensors to monitor the hot water cylinder.
  • Room temp and humidity Sensors
  • Light Sensor
  • Motion Sensor

For completion it needs:

  • PCB to be designed and built
  • An enclosure

Arduino Power Monitor Node
This is to replace my CurrentCost device. It has served really well but since adding Solar to the house I need MOAR(tm) control. I currently monitor total power use and the HydroHeat circuits. The new unit will be capable of monitoring 4 circuits. Solar, power and lights, Hydroheat and Total Power consumption. As this sits by the front door it will also need to act as a doorbell, Light sensor, motion sensor and also temperature while communicating wirelessly to MotherHub through an xbee! A busy unit.

Things left to do:

  • Finish circuit board design
  • Enclosure
  • Arduino Code

Data Logging to MySQL and Web Frontend
Motherhub currently logs to Xively here. I want more control of the data and unlimited logging of that data over time which I haven’t seen offered by anyone else yet(for free). I’m sending data from MotherHub to a Python Script running on a Raspberry Pi at the moment. My NAS has an instance of MYSQL running so I log the data there. I could run python on the NAS or even my linux proxy server so save one device and its power consumption (not that the Pi uses much) but future wise I may move all of the sensor processing to the python script and more powerful Pi. Depends how MotherHub can handle 10-20 Xbees sending in packets and all the sensor processing 🙂 I’ve just made good progress on this by getting data into the database. No doubt I have a lot more time to be spent here.

  • Testing Script robustness when accepting data over serial from MotherHub
  • Running script as daemon on the Pi
  • PHP Front end to display graphs

Learning all this as I go but really starting to have fun with it. PCB design and Python being the latest skills I’ve started learning and have to admit enjoying immensely.

This is a great start to Documenting this whole thing! I have more of a plan after putting this to a post. I will do separate posts dealing individually with the different nodes that will include all the finer details of PCB designs and code. I know I said there would be pictures at the top of this post but i think its long enough already. I will add them in to the detailed posts of each arm of the project.If you have read all this then hopefully future posts can help you achieve your own SensorNet 2000 😛 I want to hear about it!

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