During the last week I was able to build the breadboard version of the kitchen2 device. Learning from my previous problems with just partially prototyping the circuit. I’ve built it fully …i’ve connected the “production” power supply to it and the ledstrip too. The led strip is dimmed by a fet…because this was new for me I’ve consulted with some experts on the arduino irc channel about what i want to build and they have taught me the simplest cases of using Fets:
I’ve been struggling with it for days now…maybe if I write it down, it gets a clearer picture for me too ;) So…I will have multiple devices with the ability to communicate to each-other via radio. Possible challenges/problems: the system itself should be able to withstand partial crash of the infrastructure…so in case of catastrophic failure; all functioning parts should sustain their function as much as possible. this means that the control logic will be distributed and the nodes should behave in a mesh network like manner it might be possible that the RF24 modules would need multiple hops to reach the target this might not be the case, I will check this fact later - having a real mesh network is cool, but in case I dont need it at all… unauthorized 3rdparties should not interfere with the operation of the system communication protocol must be resilient to replay attacks I can’t do anything to prevent an adversary to flood the radio channels with noise… the nrf’s design is very limited…1 channel out; 5 channel in.
Creating the box After fixing the power related issue I encountered…I designed a box for the device; which could be 3d printed. I’ve started working with some nightly FreeCad version (v0.16) - I ended up using a the nightly version because I encountered some issue with its spreadsheet usage - I worked a lot to be able to enter all my data thru the spreadsheet page. So later I can come back, and this way I don’t have to be absolutely right at the first time - just change the parameter and I’m done - at least that’s the idea…FreeCad is designed for heavy use of constraint based modelling - it takes a lot of effort do design things in it.
I’ve ordered a bunch of capacitators and other gadets…to fix the problem. After my order arrived…i’ve moved the stepdown module to a prototyping board; and wired it up from there. I wanted the check that the problem still exists: so i didn’t added any capacitator…and for my biggest surprise: it worked. I thinked that: because of the different conditions…longer cabels…the noise is not that close to the other parts. I added the capacitators to the proto board…that went well to…
Last week all needed parts arrived to start with the assembly of the first member of my home automation infrastructure. This will be the kitchen sensor - i picked this because it involves many sensors and no control. Imagined operation If i walk into the kitchen…it should be aware of my presence; if the light condition are too dim - the two lamps should turn on…to supplement lighting to the specified level.
I’ve a max471 based voltage/current measurement module from ebay. It’s very straightforward to use it…snap in, measure the 2 AD outputs. But on my desk I power the arduino appliances driectly from usb. And for some reason, I only got 4.6 or 4.7 volts(i’m using some cheap hub). But having lower voltage does matter in this case, because the max471 communicates in analog form. I’ve tried this module earlier and I concluded that the max471 is precise; and works up to specs returning analog values - but I’m not really able to read the correct value; because of the lower VCC voltage.
I always try to don’t buy right away items on ebay - and place them in the cart instead. Because I’m aware that I might be changing my mind in a few days…but after approximatly a week, I submit my orders after throwing out some unneccesary items… The shipping time is usually 2-3 weeks…so I’ve plenty of time to think about it how i will be using the parts. So…in the last couple weeks I reached this ‘buying’ phase at least 2-3 times…and because my plans has changed…nowadays i’m getting packages with parts I might not need (now) ;)
I’ve tested the nrf24l01 modules on my table…and after they begin to work; I wanted to check that how far I can communicate with it – I wanted to know that I must add mesh tech to things thing or not. I have a bunch of 18650 batteries; with 3-pack battery holders. I estimated the voltage from that to be ~12.6. so I opened up the pro mini info page…even thru they wrote that 12v is the maximal voltage; I tried to open regulator’s(S80E) datasheet…my search pulled up a lot of garbage without results…so i tried to lookup what kind of regulators are on the pro mini-s…i found some pointers in a forum…and finally opened the datasheet - I quickly determined that the regulator is rated to handle up to 16V :) …so i connected the battery pack.
Our living room and kitchen is in the same space; they are separated by a half-wall. We have a table in the kitchen; with a smaller tablepiece over it…I wanted to install a led strip under the upper one. I’ve bought the led strip…the power supply for it..and then I was unable to install them; because I would need to replace the existing switch with another one…which is already at a bad position…and because I forgot to buy a box for the 220v parts i needed to install - the whole idea got stuck because of implementation problems.