General Discussion

I'm planning to use my Yubikey Neo as key to the alarm system. It has NFC and it's more secure than just an RFID tag. It can do SHA1-HMAC among other things. You can combine that with a passcode and have 2FA. Only downside: 50$ a piece. But it's a very versatile security gadget, and for me, it's worth it.

@Cliff-Karlsson said: thanks for the answer, I don't really know what a fly-back diode is or have any non-light diodes at home right now. I have a couple of optocouplers, mosfets and transistors lying around. Can I use any combination of those components to control the pump? At this small pump a mosfet will probably also work yes. To the fly-back diode: As you may already know a diode only conducts in one direction. And you may also know that a electric motor can also be used as an generator. When powering off the motor the motor will be act for a short time as "generator" due to the momentum and the stored energy in the magnetic field. The diode will be connected between the mosfet and the motor to prevent flow of current back to the mosfet in this event.

Hi, I think that board is bad air now, the board in hardware is well, but in software not, no linux suport now, this company is asking to community to provide a linux support, because they cannot do this work. and only a sdk from allwinner with android is provided. this board with linux won't work with accelerated gpu only headless and doesn't have any sata. more info https://groups.google.com/forum/#!topic/linux-sunxi/Ze_UhiO00t8 there are boards with a soc allwinner A20 that have sata port and works well with mainline linux only headless mode and basic graphics. or kernel 3.4 for graphics support. and has a community effort with distribution like armbian.com check these site for headless debian, works well. more info at linux-sunxi.org or http://linux-sunxi.org/Linux_mainlining_effort for check new features and new boards support.

Ok solution is now live :) PowerNode from GreenWave with power monitoring. I'm monitoring power consumption on DVBT reciever. When it goes up from idle, tv and speakers turn on, when goes to idle consumption it turn off all :)

@MaxG , maybe this may help a bit.

Went looking on the forums and didn't find anything.

@Cliff-Karlsson The RFXtrs433E is a bit expensive but works really well. I received mine last weekend to control my Somfy Blinds. Also I'm now able to hijack my neighbours light controls ;-) Can't wait till the next time I'll visit them, and see the look upon their face when I switch on and off their ligths without them knowing that's me doing it.

@TimO To confirm this I just 'rebuilt' my actuator node as the example humidity sensor (swapped a few links on my breadboard) and now the Pin13 LED behaves just like the other sensor node, mostly off with just a tiny flicker on each transmit.

No problem, you're welcome :)

You could combine the two ideas and create a PCB board with level shifters and the 4x2 connector.

Thank you all ... that was what I was looking for.

@hek And now for the really useful stuff: https://github.com/narkoz/hacker-scripts :+1:

Have a look at 123d.circuits.io. It has an editor like Fritzing, which you can easily toggle to schematics view or PCB design. It might fit yours needs.

Maybe 123d.circuits.io is a good alternative for MySensors users. It has an editor like Fritzing, which you can easily toggle to schematics view or PCB design. It is even able to simulate Arduino with running code! Quite impressive.

In general the readings will not be underwater. At best, I think we could cover a foot or two with RF before the signal fades to noise. Even though sound travels well underwater, RF at these frequencies do not. But what we hope to do, is take them out, leave them sealed and then download the information via a stored CSV file. That is the part we are struggling to code with right now. Sensor arrays: We are building one to ride on surfboards that has gyrometric and accelerometric capabilities as well as temperature using a sinple DS18B20 tail into the water. This is for a social science project. However, a more involved project involves pressure, temperature and conductivity (this is the hardest one to reliably measure with affordable parts). the whole shebang is used to monitor streams, rivers and as of late wells to assess the impacts of salt run-off and ground water infiltration. Currently the commercial units cost $1500 plus a reader per single instance. If we can get this to work we can install 10x the number of sensors and engage citizens and science teachers in the building of our network. Right now, I am trying to make it easy to get files out without the help (who might be 10 or not technical) having to open the units and reassemble them properly. Thus the WIFI.