Hi Dwayne The 7segment displays I applied are manufactured by Kingbright. The superbright red ( SC36-11SRWA) gives the highest luminosity for the least foward current. This is common cathode, they are also available in common anode (SA36-XX) Each package is only 7,5mm wide and the digit is relatively large in relation to the package size. Price is about 40c US per digit http://www.kingbright.com/product_main_1.php?product01=3D20050504115323&pro= duct02=3D20050525114427&level=3D20050526104503&lang=3DEnglish The Freescale differential pressure sensor is an MPXV7002DP, range being +/- 0.2 bar with a decent output, 4.75V full span, obviating the need for fancy (and costly) instrumentation amplifiers http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=3DMPXV7002 As for my position regarding microcontrollers, I was much into the idea of squeezing the max out of the least, always plumbing for the 'smallest' micro which could do the job, more out of an aversion to being accused of resorting to 'overkill' because of a lack of resourcefulness than anything which made economic sense. I've used the 630/676's before, with success but accompanied by much frustration and extra effort due to port limitations ..... volume price is $0.98 (Microchip website) The PIC16F887 is quoted at $1.78 which is about right, being available at under R20 in South Africa. For an extra 80 cents you get 44 pins, 4 full 8 bit ports plus the E port and a whole lot of bells and whistles besides, making it a dream to design with and program. So it's overkill for a HVAC controller....so what! Best Regards, On Sun, Sep 23, 2012 at 4:05 AM, Jesse Lackey wr= ote: > Speaking of OLED ... be aware of limited lifetime, things like 3000 > hours, 9000 hours, etc. is sometimes specified. Not sure if that means > the display dims to 50% (or whatever) of initial brightness, or pixels > drop out, etc. > > If it needs to be on all the time this would certainly need to be > considered. If it needs to be on only when someone is fiddling with the > menu buttons, no problemo. > > These folks may not be cheap enough, but have a nice selection and good > datasheets, etc: > > > Cheers > J > > > Perry Curling-Hope wrote: > > I have recently completed a similar design based on a low cost Freescal= e > > sensor and UP/DOWN buttons in menu driven arrangement. > > > > I had similar problems related to restrictions upon display size as the > > unit was to be embedded into the doorpost of a laboratory drying unit, > the > > doorpost being only 50mm wide overall. > > Standard LCD character displays are cheap and versatile but too wide, > tiny > > ones are too expensive, and I ended up with four tiny 7segment led > displays > > (power hungry, but this is cheaply overcome) > > > > I do not know what micro controller you are using, but your design > > description prompts two general comments. > > > > The new Enhanced Performance PIC micro controllers offer vastly increas= ed > > functionality (and pin count) at much lower prices than the older > > chips...there is no longer advantage to be gained hacking about with a > > 'small' PIC and in conjunction with shift registers and decoders to try > and > > save costs. > > > > The OLED displays will be ideal if their price is acceptable, the one y= ou > > mention supports both I2C and SPI ( 2 and 4 wire) interfaces, which are > > also supported by many of the newer PIC controllers. > > > > > > On Sat, Sep 22, 2012 at 4:17 AM, Andrew Burchill > wrote: > > > >> Hi, > >> > >> http://www.displaytech.com.hk/ > >> http://www.displaytech-canada.com/products/cogmodules.php > >> > >> any better ? > >> > >> My real problem with purchasing production parts from eBay vendors is > >>> long term supply. I need to be able to purchase parts for at least a > >>> 5 to 10 year timeframe. > >>> > >>> Please keep the suggestions coming - they all help. > >> > >> > >> regards > >> AB > >> -- > >> http://www.piclist.com PIC/SX FAQ & list archive > >> View/change your membership options at > >> http://mailman.mit.edu/mailman/listinfo/piclist > >> > > > > > > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 Perry Curling-Hope Research and Development --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .