cheaper large instrument displays - mast mount

Cooking and freezing results

I have cooked and chilled the LCD display and the result are:


Vout is a stable 14.69v

Vo measured to give best contrast is

0c -12.62v
20c -12.45v
50c -12.22v

The tests have been carried out 3 times to make sure they were consistent

At 0c the display was a tiny bit sluggish but nothing that inhibited usage, occasionally when running the race timer a second would be missed
 
ShaunG said:
I have cooked and chilled the LCD display and the result are:

Vout is a stable 14.69v

Vo measured to give best contrast is

0c -12.62v
20c -12.45v
50c -12.22v

The tests have been carried out 3 times to make sure they were consistent

At 0c the display was a tiny bit sluggish but nothing that inhibited usage, occasionally when running the race timer a second would be missed
Click to expand...

By sticking the top end of the pot to the DAC output (PA4) instead of 5V I can get 0.55V swing on Vo when I adjust the contrast using the settings and buttons. This is greater than the hot/cold voltage range you saw (12.62-12.22=0.4V).

So here is something else to try. Move the line that goes to the top end of the pot from currently Vdd (5V) to PA3.

Set the contrast to a good value at room temperature with the software contrast adjustment in settings in the middle.

Stick it in the oven and fridge again, and see if you can adjust the contrast at the low/high temperature back to a good value by not touching the pot but by just using the settings and buttons. If you can, then we may not need op-amp circuitry at all (although I would still like to make it work).

The software contrast adjustment is currently backwards using this method, but that can be easily fixed in software.
 
ShaunG said:
Hi Angus..not quite sure how to do the above

Do I need to do the following:

Keep as wired...and add a new line between pa3 and top line of pot (currently connected to DVD) remove the vdd to 5v line?
Click to expand...

The pot connections you have at the moment is at the top of the diagram.

Replace with the bottom. It's just moving one wire that currently goes from the pot to +5V to now go from the pot to PA4 instead.

You will then be adjusting the top end of the voltage divider with the voltage output from the DAC, which is on pin PA4. The other 2 pot connections remain the same.

Just noticed that it's PA4, not PA3 as shown in the rubbish diagram below, but I can't be bothered to edit and upload the bitmap again.
 
Last edited:
Finished testing in fridge/oven and all works, just about in the range..the extremes of 0 and 50c pretty much match the extremes of the contrast control perfectly

AngusMcDoon said:
The pot connections you have at the moment is at the top of the diagram.

Replace with the bottom. It's just moving one wire that currently goes from the pot to +5V to now go from the pot to PA4 instead.

You will then be adjusting the top end of the voltage divider with the voltage output from the DAC, which is on pin PA4. The other 2 pot connections remain the same.

Just noticed that it's PA4, not PA3 as shown in the rubbish diagram below, but I can't be bothered to edit and upload the bitmap again.
Click to expand...
 
Looking at the enclosures again, there was a post on pro about 2 instrument pods, the company referenced used vacuum forming and do bespoke mouldings etc(based about a mile from where I live)

Whilst their costs no doubt have the marine factor applied

Any thoughts on vacuum forming for the enclosure, If thought worthwhile I will go and see of I can meet with them this week
 
Vacuum forming is a relatively cheap method of producing custom parts. It does however have limitations.
  • It's not particularly accurate compared with, say, injection molding
  • Any deep-drawn shapes will need a noticable taper on the sides
  • There is no way to produce complex shapes, such as the interlocking profile needed to produce a watertight joint
  • Any texture is part of the original sheet material, so you cant have both textured surfaces and smooth surfaces - probably making it impossible to stick a membrane overlay to the front, or include a window for the LCD, if you want cosmetic texturing
  • The sheet material needs to be fairly thin, so it's not very strong
 
ShaunG said:
Looking at the enclosures again, there was a post on pro about 2 instrument pods, the company referenced used vacuum forming and do bespoke mouldings etc(based about a mile from where I live)

Whilst their costs no doubt have the marine factor applied

Any thoughts on vacuum forming for the enclosure, If thought worthwhile I will go and see of I can meet with them this week
Click to expand...

How about going directly to 3D printing? This would avoid making any prior investments to tooling and fixing the production globally to one supplier. For examples see this community, http://www.shapeways.com/
 
Here's the latest incarnation - remote buttons. The display is linked by two small RF modules that cost about £3 for the pair. Here's the one on the new remote handset circuit...

SDC11535.jpg


Here's the other end on the mast display...

SDC11538.jpg


Here's the new remote circuit board with 4 buttons...

SDC11536.jpg


Here they are in action...



There is still no addressing implemented to allow one remote to talk to multiple displays. I have an idea that to set the address on the display, power it up with a local button pressed (there's one on the Disco board) and that will take you into address setting mode where the display will respond to any key presses on the remote handset. Once that's done the user will be able to select one of up to 4 displays by a long button press, and then short presses will do the normal thing (select preset channel, up/down/select/cancel, etc.)

The remote handset circuit is currently taking 2 mA in standby, which is too much as that will only give a standby life of 1000 hours from 3 AA alkaline batteries. I cat get the processor (a PIC16F26K22) to wake up from idle mode on a button press interrupt, but not sleep mode for some reason. If I can get sleep mode wake-up to work then the standby life should be about a year, which is not as good as TV remote controls, but is good enough I think.

Putting the buttons on a remote handset may be cheaper in small numbers than making a custom membrane panel with 4 buttons for the front of the display. The circuitry and code for the 4 on-display buttons are still in place, it's just a different compile option now.
 
New enthusiast

Great thread, only stumbled on it two days ago. I have been thinking along the same lines as this and for the last month reserching similar ideas.
I am completely new at this sort of thing but had reserched PicAxe and Ardunino with a similar LCD display form RS.

Rather than a mast display I want to make a repeater display to add to my elderly raymarine instruments above the hatch. Mainly Mag Heading in big letters and the ability to select other seatalk / nmea sentences. The remote control looks a great idea for this as well.

I am keen to learn, and would like to copy whats been done so far. I see my skills as being average DIYer, if I could build this I might be able to explain the difficult bits after tuition from the experts.

I will trawl back though the tread to get a parts list.

All the best

Tom
 
Hi Tom, welcome to the electronics madhouse..this would work nicely as a large repeater display as well.. (Mast mounting is just an option)

I can quite happily dig out the part numbers from my Orders with rs, being new to it as well I have bought it all recently and have/am on a steep learning curve. If there is anything I can bring you up to speed on the please let me know. Angus has made amazing progress on the functionality and hardware...back to the housings
 
Parts Required

Hi Shaun

Thanks very much. I am going to place an order.
Will you cast your eye over this and see if it is correct. Ommissions and errors.

LCD Display
Graphic 240x128 STN yel/grn
http://uk.rs-online.com/web/p/lcd-d...2267573743D3533322D373232312677633D4E4F4E4526
£35.20



STMICROELECTRONICS - STM32VLDISCOVERY - STM32 Value Line Discovery Kit
http://uk.farnell.com/stmicroelectronics/stm32vldiscovery/stm32-value-line-discovery-kit/dp/2118806
£7.91

CooCox IDE Complier and ST driver download from http://www.coocox.org/CooCox_CoIDE.htm

What is the Farnell STM32F100RB I had a look on their website and none of the pictures looked the same as your or Angus's images?

MAX232 (with legs, i.e. in DIL package) and the capacitors to go with it (1uF, low voltage will do, for example 30V). Get 2 chips and 25 caps.

RS232driver/receiver,MAX232N 2T/2R DIP16
http://uk.rs-online.com/web/p/line-transceivers/1951195/
£1.09 times 2

Radial AL cap, 1uF, 50V
http://uk.rs-online.com/web/p/aluminium-capacitors/7075663/
£4.00 for 200


A RS-422 line receiver, something like Farnell part number 1210966. NMEA is RS-422. Get 2 again in case you hoover one by mistake.

TEXAS INSTRUMENTS - UA9638CPE4 - LINE DRIVER DUAL RS422, 9638, DIP8
http://uk.farnell.com/texas-instrum...r-dual-rs422-9638-dip8/dp/1210966?Ntt=1210966
£0.61 times 2



Breadboard 830 Point Solderless PCB Bread Board MB-102 MB102
http://www.ebay.co.uk/itm/Breadboar...tem1e7387f41d&clk_rvr_id=413263935342&afsrc=1
£4.75

Pin Header 36 way SIL Straight 2.54 0.1" x 20pcs x 36 pin strips 720 Gold pins
http://www.ebay.co.uk/itm/Pin-Heade...tem35c1415b28&clk_rvr_id=413257176416&afsrc=1
£1.45

3m Solder Wick Mop/Sucker Braid Component Remover
http://www.ebay.co.uk/itm/3m-Solder.../230417100919?clk_rvr_id=413262448319&afsrc=1
£3.45

Some solid core cable to go into the breadboards, stranded doesn't work too well.
Should I get Blue or Brown? I guess this comes out of domestic lighting cable.

Some 9 pin D-SUB connectors so that you can connect a serial line to a computer's RS232 port. Which ones?

10k pot
Audio single pot. 10K Vertical 30mm,1B
http://uk.rs-online.com/web/p/potentiometers/7293653/
£0.38

Some Button Momentary action switches
6x6mm tactile switch,9.5mm H 1.6N
http://uk.rs-online.com/web/p/tactile-switches/4791435/
£0.082 times 20

Quality hot tweezer soldering station plus 70W solder iron BK 3000LF-T
http://www.ebay.co.uk/itm/Quality-h...tem4ab969ba59&clk_rvr_id=413268721208&afsrc=1
£94.99

Or the link you said:-
http://www.ebay.co.uk/itm/170935042151

I think this would get me upto the non rf stage, and I would be grateful for any code I could have. I have some hobbist coding experience in VBA and PHP. I have written routines for Sunrise Sunset based on UTC and Lat and Long which could be a feature, and I was thinking about deriving tidal vectors for display, useful for both cruisers and racers, although this would have to include leeway as well.

Thanks

Tom
 
Here are the part numbers from rs for all the bits I have bought so far


Discovery board - 7276526

LCD - 5327221

Sil connector x 6pk - 7457071

10k pot - 7293454

6mm switches x 6 - 4791413

Max 233 (does not need caps) - 152215

Serial plug socket - 5443749

Serial plug - 5443727

I have not sorted the 422 line driver yet

The breadboard I already had, as well as the soldering iron and solder..the solder iron you have listed is expensive but probably worhtwhile in the long run, I ended up getting a solder station from eBay for £40 as an interim, yet to turn up though..for a one off you could get away with a normal fine tip solder iron from somewhere like maplins

Wire..is fairly fine gauge solid core..about 1mm, sometimes called bell wire..in the true terms or an Angus YAPP the wire should be brown :)

Coocox - spot on..took me a while to sort that all out with the gcc complied etc..Definetly worth reading the site for an hour first

I will pm my phone number so that you can contact me of you want to talk through any of it first..I can send code..but I am sure that Angus has a later version
 
Is it now time to get a pic programmer and bits as well? . Wireless control is simply amazing..I have run plenty of nmea data through and all seems to work well..

I have started some drawings for the internal setup/layout

Essentially as discussed before

LCD pcb defines size of other pcb,s and mounting hole centres

1. LCD pcb uses sil
2. Ancillary components on secondary pcb the same size as the LCD pcb..pcb has sil socket for LCD to connect to on front face. Rear face has 2xsil socket for a discovery board (or a later high performance board) to connect to...all held together with spacers and screwed/bolted to housing

The above should allow for easy upgrades of the any of the 3 pcb's to alter performance/function etc...essentially a modular system

Any thoughts..if we are happy ish with the above I can use the pcb pcb as the sizing for the housing and make a reasonable stab at total sizing :)
 
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