Clothes dryer project part 2

I haven’t really done any work on the dryer at all, none of the software is done and all I did was test that the new dual channel humidity and temperature sensing would work. By the way to do the dual channel I had to use a quad analogue switch to switch the I2C since the ebay sensors I’ve got don’t allow a choice of the I2C address.

What I have been doing is designing a PCB for the controller part, and tonight I sent if of to Seeed Studio to get fabbed. This cost me just over $20 Australian, although I have to wait from between 15 – 30 days for the boards to arrive (I get 10 although I doubt I will ever use more than one). I am quite nervous that the fab will fail or that my design can’t be fabbed, or, of course that I haven’t transcribed the circuit from my hand wired version.

Kikad takes a little bit to get used to but it wasn’t that difficult to design this board; not that it’s a very big board. The last time I had a board I designed made I had to lay it out with black tape, I hardly recall, but it must have been painful. Although neither method is as painful as doing point to point wiring, even at this small scale. I’ve done a board with point to point soldered connections using wire wrap wire, where each end needs to be stripped, that had hundreds of connections. I can’t believe I did it now. That was the graphics terminal, I wish I still had it, I would frame it an put it on the wall.

How the design looks in Kikad.

How the design looks in Kikad.

This is the board in the gerber viewer.

This is the board in the gerber viewer.

I am not motivated at present to do much else at the moment even though I have had some good ideas about the software; once I can measure the ambient humidity then I think I can make the thing work more sensibly. I have again found that clothes that are hung on the line still dry faster and clothes dryed in the dryer sometimes have a faint smell about them. I think it depends on how much sun is available. I really need to design and build the new air extracting chimney hat and of course create at least version 2 of the software ( to control the fan by comparing inside and outside humidity ).

Just awaiting my board now.

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