cheaper large instrument displays - mast mount

[Tom_Brewis]

Funnily enough just posting a question or two is quite encouraging, and its nice to know people are still intrested.
I have just been the keen watcher who was intrested to have a fiddle. The result is that due to Angus's tutoring i have a proto type working display with remote. Over the next couple of days i am trying to put it in a box so that at the weekend i can do some sea trials.
As Angus said at the beginning the box is the problem, this is most counter intuative to the non techie.

 

[TSB240]

The major component where I don't know what is happening is the casing. Shaun hasn't posted recently.

There are 4 working displays (me 2, Tom 1, Shaun 1) and 2 working remote handsets (me 1, Tom 1). Only 2 Discovery boards were harmed in the process

So, in summary, software almost complete, hardware design (excluding PCB) almost complete, PCB layout not started, case Shaun to report.

This is of course only to hobby standards. Nothing done on EMC compliance or European standards testing, although best practice techniques have been used in software for EMC.

Angus

My son could produce 3D printed cases for your prototypes if you require an intermediate solution.

He has had some success with printing cases for Pi projects and others. He is capable of taking a Cad design and developing it for 3D printing.

It is also an advantage that he is a qualified electronic engineer and is a senior project manager working on embedded software so will more than understand all your gobldegook

This is obviously not a long term solution but might help get your prototypes out under test in real life situations.

Pm me if you want to make contact.

Steve

 

[Jabamusic]

I am off to have a chat with a man who has a 3D printer this afternoon as well - no promises, but it might come to something and as TSB240 says, it might help to get the prototypes out in the field.

From memory, I know Shaun was planning to meet with a firm prior to Christmas, but was taken ill. I'm sure he'll get back onto it asap.

 

[lustyd]

Regarding the case, wouldn't it be easy enough to create a mould and use epoxy/poly resin for the sides bonded to a transparent polycarb front? a back could then easily be screwed in place with a rubber seal to make this water tight enough.

Out of interest, does anyone have an up to date parts list? I'm thinking of building one, having just read nearly 60 pages If not, can someone confirm whether the list Tom posted a while ago is still pretty up to date?

 

[Tom_Brewis]

The main list i posted was updated in the next post by Shaun and this is what i started with, however its probably a good idea to continue forward in time from that post and get everything at once. I bought everthing from RS except the RF modules which came from Hong Kong a bit slowly , and a few capacitors and resistors from Maplins.

Good luck lustyd and do PM me if I can help, however if its difficult Angus is the guru.

Progress update. Contrast working digitally and it appears that the 10k pot just works like an on off switch for the contrast. The contrast changes from nil to software control at about half rotation.

Madly working with soldering iron to get it all in a box before the sea trials!

 

[AngusMcDoon]

I'll do a parts list.

 

[AngusMcDoon]

Here it is. I'll update it as I find more information. RS part numbers and 1 off price in pence including VAT in brackets for some parts.

Resistor RS stock numbers not shown, you can hunt for those yourself. 5% tolerance quarter Watt ones are fine, for example RS 707-7745.

I've not given stock numbers for the push buttons as the type you need depends on how you are mounting them.

For the mast display

STM32F100RB Discovery board RS 727-6526 (984)
240x128 LCD Monochrome display RS 532-7221 (4224)
MOSFET RS 719-2881 (16)
Op-amp TL061CN RS 355-5042 (31)
4 push to make push buttons if you don't want to build a remote.
1 10k resistor (2)
1 10k linear potentiometer RS 729-3574 (48)
1 14k resistor (2)
2 150k resistor (4)
RF module pair if you want to build a remote handset...
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=190676509436&ssPageName=ADME:X:RTQ:GB:1123 (255 for pair)

The display will run from a USB cable between the Discovery board and a PC's USB socket. If you want to run it from a 12V supply then you will need a 5V voltage regulator, for example a cheapie is RS 686-9820P (22). This needs the following capacitors:
1 0.33 uF RS 684-2046
1 0.1 uF RS 547-2876

For those of a Seatalk disposition who want the Seatalk interface, which is optional...
1 BC556 RS 546-1545 (12)
1 10k resistor (2)
1 2.2k resistor (2)
1 4.7k resistor (2)
1 470 ohm resistor (2)
1 6.8k resistor (2)
SFH615A opto-isolator RS 708-5480 (38)

For those who want NMEA input - I've not done anything with the electronic design as I don't have a NMEA system. I have tested with NMEA messages coming in via RS232, and use a MAX232 interface chip. This will almost certainly work for proper NMEA too, but really it should be a RS422 line receiver. Someone else can figure out the right chip to use instead of this...
MAX232 RS 195-1195
5 1uF capacitors RS 707-5663

You will also need 2 breadboards for the display, or Veroboard, which can be bought from EBay.



For the handheld remote...

PIC18F24K22 RS 715-4429 (251)
Battery holder RS 512-3552 (41)
Green LED RS 228-6004 (7)
10uF capacitor RS 547-2927
100nF capacitor RS 538-1635
100 ohm resistor (2)
4 push to make push buttons
2xAAA batteries
RF module, see above

You will need a PICKit2 programmer, genuine Microchip or clone, for example...
http://www.ebay.co.uk/itm/iCP01v2-U...309?pt=LH_DefaultDomain_0&hash=item416dff2a5d

You will also need 1 breadboard or Veroboard which can be bought from EBay.

Display Processor Pin Schedule

PB1 Seatalk receive data line

PB5 Button 1
PB6 Button 2
PB7 Button 3
PB8 Button 4

PA1 Analog volts in for battery voltage - needs resistor divider to scale volts

PB0 PWM Backlight out - goes to a MOSFET that switches the backlight

PC8 LCD C/D
PC9 LCD /RD
PC10 LCD /WR
PC11 LCD /RESET
PC0-PC7 LCD DB0-DB7

PA4 DAC Out contrast

PB2 Boot

PA9 USART1 Debug print

PA3 USART2 NMEA receive

PA0 Address set request button - user button on the Discovery board

PB10 RF IRQ
PB12 RF CSN
PB11 RF CE
PB13 RF SPI SCK
PB14 RF SPI MISO
PB15 RF SPI MOSI

 

[lustyd]

Thanks Angus, hopefully I'll be ordering this week some time.
Cheers
Dave

 

[Jabamusic]

Thanks Angus, hopefully I'll be ordering this week some time.
Cheers
Dave

When you have done that, it might be interesting to let us know what the cost is for all those bits.

Thanks

 

[lustyd]

When you have done that, it might be interesting to let us know what the cost is for all those bits.

Thanks

Under £100 by the look of it so not bad at all if a reasonable case can be made. I'll be honest I neither need or want a mast display, I just want to play with the toys but I figured if I get the same parts I can at least see a good project working before I come up with something useful myself This thread has shown me how easy it actually is to make electronic things (I already know how to program...) so I'm really impressed so far. When I say easy I mean in terms of making the electronics, I realise Angus probably spent a few months coding to get such a finished looking program. I always imagined it would be much more involved regarding soldering chips and programming in assembler etc!

 

[AngusMcDoon]

My son could produce 3D printed cases for your prototypes if you require an intermediate solution.

Thank you for the offer, but like Jaba I neither need nor want a mast display on my boat, so I'm not really interested in doing the case part. Anyone else want to?

 

[BruceDanforth]

Sorry for the quietness..I have been unwell the last couple of weeks and missed my meeting with the plastics people..I will be on to it first thing in the new year

Anything happening on this?

 

[Jabamusic]

Thank you for the offer, but like Jaba I neither need nor want a mast display on my boat, so I'm not really interested in doing the case part. Anyone else want to?

- Actually, I think it was LUSTYD who said "I'll be honest I neither need or want a mast display, I just want to play with the toys...."

I would love to put one of these things together, I'm just hoping that I will be able to install it on the instrument pod above the hatchway as a repeater instrument, so the case size and dimensions are goign to be fairly important.

 

[Tom_Brewis]

Sea trials did not work. As I have not implemented sea talk and was hoping to use a rs232 socket that supplies a laptop. Unfortunatley this only supplies gps data at the wrong rate. So rather than trying to take short cuts I had better make the sea talk interface.
However good to be out sailing again.

 

[Tom_Brewis]

- , I'm just hoping that I will be able to install it on the instrument pod above the hatchway as a repeater instrument, so the case size and dimensions are goign to be fairly important.

This is my goal as well. I think I want two.

 

[pagoda]

Sea trials did not work. As I have not implemented sea talk and was hoping to use a rs232 socket that supplies a laptop. Unfortunatley this only supplies gps data at the wrong rate. So rather than trying to take short cuts I had better make the sea talk interface.
However good to be out sailing again.

Surely it's easy enough to tweak the serial (receiving) baud rate to accommodate the existing GPS transmision rate??
The devices I'm working with spit out NMEA senteneces (TTL) at 9600 - rather than the basic 4800 rate. It gives the parsing software less time to process, but as far as I can see, all I needed to do was match baud rates? So far so good.

Graeme

 

[AngusMcDoon]

Sea trials did not work. As I have not implemented sea talk and was hoping to use a rs232 socket that supplies a laptop. Unfortunately this only supplies gps data at the wrong rate. So rather than trying to take short cuts I had better make the sea talk interface.

Seatalk would not have worked either. I have fixed a few things today. Most of the Seatalk messages work now although there are 3 that I know don't yet and others I haven't been able to test, like distance to mark and XTE. Seatalk is more basic than NMEA. It only really puts on the bus measured data from the transducers. Other stuff has to be calculated. For example you can read apparent wind speed/direction and boat speed from Seatalk, but if you want true wind speed/direction you have to calculate it.

You need these parts for the Seatalk interface...

1 BC556 RS 546-1545
1 10k resistor
1 2.2k resistor
1 4.7k resistor
1 470 ohm resistor
1 6.8k resistor
SFH615A opto-isolator RS 708-5480

My Seatalk hardware is a cut down version of Thomas Knauf's because it is read only, but I have added an opto-isolator as the data line in Seatalk is 12 volts. I'll send updated software and a schematic.

Nigel Mercier has posted an alternative Seatalk interface which you may like to try.

 

[AngusMcDoon]

Surely it's easy enough to tweak the serial (receiving) baud rate to accommodate the existing GPS transmision rate??

It is, but it's a software rebuild as it is not configurable in the settings on the display. It could be. Should it be? How many people have NMEA at rates other than 4800? What rates should be available?

 

[pagoda]

It is, but it's a software rebuild as it is not configurable in the settings on the display. It could be.

OK, that was a misunderstanding... I hadn't quite realised that was a problem.. I'm accustomed to re-building software as and when I need to. Just another compile / link / burn event (One more of many!)

Graeme

 

[Tom_Brewis]

Thanks for the shopping list Angus