strawberry systems

the code so far…

nicholas — Thu, 15 Oct 2009 10:39:11 +0000

very messy and needs a lot of sorting out….but it does work on our functioning system. manages delta t and also secondary heating if needed.

click the link to download…

code so far

display module with 4 button interface…

nicholas — Thu, 15 Oct 2009 10:09:57 +0000

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.

propeller pin assignments table…

nicholas — Thu, 15 Oct 2009 09:42:22 +0000

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.

parallax serial terminal…a star!!!

nicholas — Sun, 11 Oct 2009 21:25:37 +0000

readings coming back from the pst.

first readings fed back…

nicholas — Sun, 11 Oct 2009 21:21:57 +0000

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…

same system showing the sensor wires coming in…

nicholas — Sun, 11 Oct 2009 21:17:59 +0000

‘lash up’ in place and controlling the system…

nicholas — Sun, 11 Oct 2009 21:05:48 +0000

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…

the analogue ‘lash up’…

nicholas — Sun, 11 Oct 2009 20:57:14 +0000

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.

controller…

nicholas — Sat, 10 Oct 2009 11:09:35 +0000

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…

pump and filling the system..

nicholas — Sat, 10 Oct 2009 09:25:32 +0000

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…