cheaper large instrument displays - mast mount

I went to see these guys today about housings http://crdm.co.uk/

Really nice guys and very helpful, they treated me very well and gave me the full tour as well as plenty of instruction in the processes that they use

The outcome was that they can easily do what we need, in just about any material at a very high resolution, some of the examples they showed me were stunning..

They are going to come back with some idea of pricing based on a run of 10 units..they have said it won't cost much, what that is relevant to they want say :/

Tom, I am not at home for a few days, as soon as I get back I will send some over

Angus, thank you for clarifying the Fsf, i will make sure I fully abide by the requirements

Oh, I have a notification that my pic programmer has arrived :) another new toy to get to grips with


Back to housings...anyone have any likes or dislikes on design/colour/material? I really do have the artistic/product design skills of paint drying. I was imagining something quite similar to raymarine/b&g..thought it does seem a little Samey and we could really go to town, the cost differential on appearance cam across as being minimal

So another abs type housing or something funky and special without being 'out there'. iMastdisplay esq
 
I wonder if rs has a batch of dodgy displays? Mine is dodgy in the same place although only 1 line of pixels

I would return it, but don't see this as being the me I would use in anything on a boat, more a display to experiment, won't feel quite so bad when I blow it up then
 
mikefleetwood said:
I used a 3.3(ish) volt "button" cell to power the PIC and transmitter direct - neither device seems particularly fussy about supply voltage, so no regulator required.

I included a transistor so the PIC could switch the transmitter on when needed.
Click to expand...

Not using a regulator is a good idea that I had not thought of. Save another 50p!

The RF module only takes 10mA maximum, so I guess I could power it straight from one of the processor's GPIO pins, switch it off when not needed, and save another 12p transistor cost :)
 
To test the addressing from the remote I've made up another display. I used red wires this time to distinguish the two :). Here are the two displays and the remote...

SDC11541.jpg


Each display has an address which can be from 1 to 4...

SDC11543.jpg

SDC11549.jpg


A display's address is set like this...

SDC11551.jpg


The address setting box comes up in these circumstances...

1) The display is new and has been switched on for the first time
2) The user has just reset all settings to defaults
3) And just in case something goes wrong with the former 2 methods, the display is powered up with the user button held down.

Once the address of each display is set it is stored in flash memory and remains there after power is turned off. I see address setting as something done once when the displays are installed and then not done again.

With the handset a display is selected by a long press on one of the 4 buttons. When a display is selected a small triangle appears in the bottom left corner so you can see which display you are talking to. Then the 4 buttons work in the normal way with short button presses on the remote.

You can see it working with the 2 displays here...

 
I have rewritten the remote handset code for the PIC16F882 processor rather than the PIC18F26K22 processor used at the moment. The 16F one costs £1.54 each (buying 5) rather than £2.31 each (buying 10) for the 18F, so a £ saved in component costs.

65% of the code space in the 16F882 is used at the moment which means not too much wasted and some spare if needed. I can't find a cheaper processor that has at least 4 interrupt-on-change (and wake from sleep) pins and hardware SPI (pins of which which don't conflict with the IOC pins), but if anyone knows of one...

Both claim to use less than a microAmp in sleep mode, although I haven't been able to get the 18F26K22 that low so far.
 
Last edited:
ShaunG said:
Any rough idea on a general size so I can talk indicative costs?
Click to expand...

Pretty much the only components are the 28 pin 16F883, a 3V CR2025 2p coin sized battery and the RF module (2cm x 1cm).

If it is going to be made properly with a surface mount PCB anything big enough to have 4 in-line buttons on would be big enough - car key fob sort of thing. RS have off the shelf 4 button keyfob enclosures, but the buttons are not in-line and they require a surface mount PCB to be made because of the lack of size - see part number 540-1458.

If it is going to be made up in small numbers by hand soldering onto either a PCB or Veroboard then it will be better to use the PDIP pin format processor, and the case will need to be a bit bigger - for example RS 741-7373. I have not done accurate measurements though. You are going to need to get a CR2025 and its holder in whatever circuit board is needed.

Batteries...

http://www.budgetbatteries.co.uk/22...5-size-lithium-3v-150mah-gp-coin-button-cell/

RF module...

http://www.ebay.co.uk/itm/2-PCS-NRF...031?pt=LH_DefaultDomain_0&hash=item4d00f5e23f
 
AngusMcDoon said:
If it is going to be made up in small numbers by hand soldering onto either a PCB or Veroboard then it will be better to use the PDIP pin format processor, and the case will need to be a bit bigger - for example RS 741-7373. I have not done accurate measurements though. You are going to need to get a CR2025 and its holder in whatever circuit board is needed.
Click to expand...

By the way - don't be scared off by the idea of hand-assembling surface mount. Once you have a suitable design for the PCB, many maufacturers can make also produce a stencil for applying solder pastem pretty cheaply. All you need is a small tube of the paste from RS, etc and something to use as a "squeegee" - it's a bit like screen printing. A steady hand and a pair of tweezers for placing the parts (illuminated magnifying glass is useful!) - then flow the solder in the domestic oven (whilst SWMBO is out!). A cheap digital thermometer with high-temp thermocouple probe is useful as the oven thermostat won't be accurate enough.
 
mikefleetwood said:
By the way - don't be scared off by the idea of hand-assembling surface mount...
Click to expand...
I actually prefer SM components, when you consider the time for drilling and bending, they are quicker. Normally cheaper as well.

I solder by tinning one of the pads, placing the component, then melting the solder while holding it in place, then make all the other joints, including the first.
 
ShaunG said:
Hi mike,
Would you know of anywhere to read up on the oven method..sounds really interesting
Click to expand...

I'll have a look - I may have a saved link somewhere that I can send you.

The solder reflow (in the oven) is the easy bit. You need to poke the thermocouple probe into a convenient hole in the PCB to measure the surface temperature. You should be able to find a suitable solder temperature profile in the chip data sheets - I usually heat it to 180-200 degrees and hold it for a couple of minutes to activate the flux, then raise the temperature to 250 degrees to flow the solder - usually switching off a little early as the temperature will keep rising for a while - then open the door to let it cool.

I'm not sure there's any links to the rest of the process, but I'll see what I can find - otherwise I'll write my own description.
 
nigelmercier said:
I actually prefer SM components, when you consider the time for drilling and bending, they are quicker. Normally cheaper as well.

I solder by tinning one of the pads, placing the component, then melting the solder while holding it in place, then make all the other joints, including the first.
Click to expand...

You may have guessed - I also prefer surface mount. Pretty much the only time I don't use it is when the board gets too large to conveniently process with my, fairly crude, setup. Usually because the board size is dictated by the need for lots of connectors or front panel controls. The maximum size I can usually handle is about 200x200mm (although I do have one board thats about 300x400mm, but fortunately I don't make that product any more) - if it needs to be bigger than that, the plan is to break it down into managable modules.

I always use solder paste and stencil, followed by reflow in an oven - it's much quicker and gives the neatest results.
 
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