One of our main hardware design philosophies is using common, inexpensive components.  We would like system builders to be able to find a majority of what they need at their local electronics store, hardware store, auto parts store, etc.  Some of our previous control modules were built entirely from components purchased at Radio Shack and McLendon Hardware.  Our current control modules use slightly more exotic, but still readily available components for the sake of lower cost, higher speed, and reliability.

 Two other aspects of our design philosophy are keeping things simple and finding new uses for old hardware.  Most of our equipment communicates with the host PC over serial.  I have been asked many times, “Why don’t you make a USB version?”  The answer to that question is that it’s not necessary.  Most old computers have at least one serial port.  Among the computers we currently use are a mini-itx PC that was once a NAS, and an old laptop with a broken screen.  If it’s necessary to use a newer computer that doesn’t have a serial port, USB to serial adapters are readily available for under $10.  We also use make frequent use of used ATX power supplies.  They are extremely versatile and provide more power than exotic power supplies that are ten times more expensive.

 One of our modules has 8 transistors which can each switch up to 100 volts DC at 8 amps, or be bypassed to use a channel for digital input. In our mash control system, we use one such module to switch propane solenoid valves, fire the burner ignition (powered by ignition coils from the auto parts store), and detect the presence of flames via thermocouples (we're exploring other, faster reacting options for the flame detector). They could also be used to control irrigation systems, barbecue smokers, DC lighting, etc. I will be prototyping v0.4 soon, which will hopefully become v1.0.

 Another one of our modules has two triacs which can each switch AC devices up to 240V at 20A, or be run in parallel to handle up to 40A. In our mash control system we use one to switch the circulation pump. We also use them to control refrigeration, coolant pumps, heating, and ventilation in our fermentation temperature controller, and to control our keg cleaner. They could also be used for a variety of home control applications. Basically anything that plugs into the wall. I’m working on v0.2 at the moment.

 Our existing sensors are the flame detector mentioned above, as well as temperature sensors with a range of -40C to 100C. We're also working on extended range temperature sensors, pressure (weight) sensors, current transducers, inductance transducers, humidity sensors, flame intensity sensors, and smoke intensity sensors.

 The total cost in parts of the 8 channel DC module is around $25. The 2 channel AC module is around $10. Temperature sensors are around $5 each. We're not sure if we are going to leave people on their own for building this stuff, sell bare PCBs, sell kits, or sell assembled units. There are some legalities we need to explore first.


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