Hardware pH Monitoring
pH Monitoring I would like to automate pH control of my swimming pool, but it has proven to be a much more complex task than I had imagined. My pool has an electrolytic chlorine generator. The pool contains salt, and the chlorinator generates Chlorine by electrolysis. In many ways this is an ideal way to sanitise a pool, but the chlorinator causes the pH to rise, which requires the regular addition of acid to bring the pH back within acceptable limits. In theory it should be easy enough to automate this. But it’s not as easy as you might think. I once bought and installed a commercial pH controller. On the first night it was installed, it pumped an entire 5 litre container of acid into the pool. There was no way to investigate what had happened, and the instructions did not explain the algorithm being used. I never gave…
Hardware Pool Temp Sensor
Pool Temperature Sensor My pool temperature sensor has been working reliably for almost five years now, so I thought it was worth showing how I made it. It’s a DS18S20 on the end of a piece of cat-5 cable. The sensor is fed down a length of ¼” transparent plastic tube. This type of tube is used for wine-making, although I found it cheapest at my local boat shop. I formed a seal on one end by melting it inside a copper end-stop – the 15mm type used for plumbing. Hold the copper stop-end in a mole wrench and heat it gently on a gas hob, then gently feed the plastic tube into it. It takes a few minutes but the tube does eventually melt. When it’s done, cool it in cold water and saw the copper end-stop off. You have a totally water-tight end-stop that will never come off…
Hardware System
System This is a rough schematic of some of a system. Felix runs on an ancient Dell laptop running Windows 2000. It is connected to a CM11 X10 interface and a DS9490R USB 1-Wire interface. There are several DS1820 temperature sensors around the house. A cable runs out to the poolshed, where a 1-Wire hub connects numerous other devices It has been a constant battle to keep the 1-Wire cabling tidy. Finally, we have it beaten but only after several iterations. The final breakthrough was a large plastic junction box in the poolshed, which houses the hub, power supply, and other 1-Wire devices. It looks just great .. with the lid closed. The system is performing more and more automation tasks. The most critical task we have is maintenance of the pool pH, and we’ll be discussing that in more detail in a separate article.
Hardware Supported
Hardware Supported by Felix One-Wire Hardware Felix should be able to support any devices based on the following chips: Chip Description Channels and Features Supported DS1820 Temperature sensor Temperature DS2405 Single switch PIO DS2406 Dual addressable switch Channel A, Channel B, Vcc DS2408 Eight channel switch Bit 0 – bit 7 DS2409 MicroLAN Coupler (Hub chip) Felix automatically detects and supports any arbitrary network topology using one-wire hubs based on the DS2409. Hubs can be nested up to four levels deep. DS2413 Dual addressable switch Channel A, Channel B DS2423 Quad Counter Count A and B DS2438 Battery monitor Temperature, Vad, Vdd, Current DS2450 Quad A/D Converter A,B,C,D Input mode only. All channels are configured to input range 5.12volts Alarm thresholds not supported DS2760 Battery monitor Temperature, voltage, current WS603 Weather instrument Temperature, wind speed, wind direction, light level, supply voltage X10 Hardware X10 support in Felix is currently quite…
Hardware
Hardware Felix currently supports 1-Wire and X10 hardware. There are many excellent websites describing 1-wire and X10 hardware, and there seems little point in replicating much of that information here. However, in case you are a complete novice, here is a basic introduction. 1-Wire The really cool thing about the 1-wire network is that you can daisy-chain lots of devices onto the same pair of wires… You can get started with just a PC interface, either USB or serial, some DS1820 temperature sensors, and some cable. The DS1820 is really easy to use, requiring only two connections and no power supply. For most home uses, you can hook up as many devices as you want, using cables about as long as you’d ever need in a normal house. Each 1-wire device has a completely unique address burned into it during manufacture. Something like EF000800DB2A0610. This number allows software…
ScreenShots-WAP
WAP (Mobile Phone) Felix works on mobile phones too! Only Panels are supported on WAP, but you can make them do exactly what you need. For example:
ScreenShot-Scripts
Scripts Felix has a powerful Scripts language, enabling it to do almost anything.
ScreenShot-DataExport
Data Export Data can be exported in several different formats:
ScreenShot-Graphs
Graphs Felix 1.44 allows you to configure graphs and tables showing data from the internal SQL database.
ScreenShot-Panels
Panels Panels allow you to break a large system into separate sub-systems, and they provide a simpler, safer user interface for non-technical users. You can configure panels to include your own selection of Devices and other controls: Here’s our pool control panel: And our outdoor lighting panel. This time we’re logged on in user mode, so the only things you can access are the panels: