strawberry systems

here’s a shot of the new 2×16 lcd display module.  Tony’s mounted it on a parallax propeller proto board so it’s got the microcontroller on the back…there’s also 4 buttons to have a play with.  now I need to program up some sort of 4 button interface to control setting variables in the code…

still doesn’t look much like a DSHW controller but when the code’s sorted and it’s mounted on it’s own bespoke pcb it should hold it’s own against any delta T controller out there…and it will have our secret weapon….the ‘bath button’.  All the spin code for the microcontroller as it is will be posted on the blog so if you want to reprogram or tinker with the code you’re welcome to do so.

check out parallax

and of course spinvent

to gen up on the propeller.

here’s a graphic showing how we’re going to allocate the 32 pins on the propeller microcontroller.  using a parallel lcd display is much cheaper than serial but uses up quite a few pins.  if you need more free pins then it’d be worth considering a serial display.

readings coming back from the pst.

here’s the old laptop kindly donated by swoz.  it’s showing the readings from the analogue to digital ‘lash up’ …to be honest they were’nt all that credible and whilst the syetem functioned fine it was clear that digital to digital was the way to go…

here’s a pic of the analogue to digital controller in place controlling the solar flat plate hot water system.  it worked pretty well but we kind of knew that it wasn’t going to ‘cut the mustard’ and would eventually be replaced…

here’s the first attempt…it’s not pretty but it sort of did the job that was required of it (thanks to tony)…there’s an analogue sensor (can’t remember which one) and an ADC and that feeds into the parallax propeller chip which decides whether to turn on the wilo pump or not using delta T.

and so to the controller…here’s the parallax propeller microcontroller demo board with an ADC chip (analog to digital converter) in test mode on the breadboard.  To start with the controller needed an ADC as we used analog temperature sensors but we switched to digita sensors  as they don’t need extra components and are more or less ‘plug-and-play’ with the Propeller thanks to the ready-made software object…

once the panel was finished it was mounted on the roof and plumbed in…the picture is of the pump that was choses.  wilo gold standard central heating pump that operates at 18watts on the most economical setting.  system was filled with water and a pressure of 1 bar acheived by simply running a hosepipe up the hill till it was 3o feet higher than the highest point on the system.  when water came out of the top of the hosepipe then the system was at 1 bar…

eureka!  it worked a dream…in the photo you can see the outpipe.  must have taken the photo before testing and then got so carried away with the results that I forgot to take a shot of the steaming hot water that resulted…

it was a hot day so I hooked up a cold water hosepipe…

harry bathing in reflected glory…

harry (dad) holding glass scrounged from a local glaziers who were happy to help. it was originally a £200 sealed unit that I got for £20 because it’s seal had failed.  was destined for the skip.   because the panel only needs single glazing I’ve only used £10 worth so far so if there’s a need for a further panel then I already have the glass…talking nicely to local building suppliers will almost always pay off!!!

here’s the collector and frame just before being assembled…the frame is made out of a ply board with a timber surround and a kingspan sheet for insulation…

after cleaning off all the flux everything copper was given a coating of matte black stove paint.  it’s rated to 650 deg C so should hold up all right…

here’s an image of the collector all soldered up…took about a kilo of solder to get a good contact between the collector plate and the copper pipes…

the first posting on the blog!

what’s needed is to trace back a number of steps and show how we’ve got to where we are now…we’ll do that with lots of photos and documents to show the history of the system.  any questions please put a comment on the relevant posting and we’ll get back to you…

it all started back in April as with many things these days with a bit of googling…which led me to here.

http://www.reuk.co.uk/DIY-Solar-Water-Heating-Prototype.htm

there and then I decided that I wanted to have a go at a full size system based on this prototype.   the photo shows the collector in early stages…basically a couple of redundant hot water tanks topped and tailed and flattened out to become the collector…

on top you can see the copper pipes