The most challenging part of building your own DIY chart plotter or some other marine device with a display, is finding a suitable, and reasonably priced, high brightness, sunlight readable monitor. There is a lot of discussion about it, for example on OpenCPN wiki and on cruisersforum.com. I spend probably north of 100 hours researching the alternatives for a boat display and wanted to share the information below.
Use cases for the marine monitor
The display would be used indoors or outdoors as a chart plotter or other marine device display (e.g. engine data display or NMEA 2000 data display) on a boat or a yacht.
It is to be noted that many high brightness monitors are expensive. I have listed below only the monitors that are below $1,000 (or 1 000€) for larger sizes and in $50-$500 range for smaller ones. The prices listed below are prices that are specified on the website. In addition to the price, there will, in most cases, be taxes and shipping costs and possibly customs fees.
If you are using the monitor inside the cabin, you have a lot of choices for a high-brightness monitor and can save considerably compared to buying a commercial chartplotter. If you need a monitor that can be left outside, the options are much more limited and the cost starts to be closer to the commercial chartplotters, except if you want to get a large display of 15″ or more, which size chartplotters are extremely expensive.
Brightness (nits or Cd/m2)
Displays used in outdoor environment (in direct sunlight) must be really bright. This is especially true with marine displays. Brightness is typically measured with Cd/m2 (Candela per square meter), which is also called nit.
I marine chart plotter display used outdoors should have a brightness of 1000 nits (1000 Cd/m2) or more, many of the commercial chart plotters are in 1500 nits. A display showing engine gauges etc. can probably be something like 600-800 nits depending on the contrast of the colors used. If the display is used only indoors inside cabin, the brightness can in many cases be less. Tablet with 500 nits brightness works very well indoors (although at least iPads have such an excellent anti-reflective layer on the screen that it may be the reason why it works also in quite bright environments, 500 nits monitor may not work that well).
On the other hand, in night navigation, you’ll need to be able to dim the display to a very low brightness. You can do that, at least partially, by changing the color scheme on the application, but it would be good if the display would actually lower the brightness of the backlight LEDs, preferably automatically.
Anti-reflective (anti-glare) layer
Tablets have advanced anti-reflective layers and therefore work decently well even outdoors considering their relatively moderate nits ratings of 500 or 600 nits. Many monitors designed for outdoor use (sunlight viewable monitors) also have an anti-reflective layer optically bonded to the display. Anti-reflective layer absorbs some of the display brightness, but makes the viewability much better in direct sunlight.
Touchscreen is not build into the display but another layer bonded to the top of the display. There are resistive and capacitive touchscreens. Capacitive is more sensitive, but does not work well if wet and does not work at all with gloves. Resistive requires a bit more pressure and is not as accurate, but can be used with gloves on and does not mind a bit of water on top of it. Touchscreen absorbs some of the brightness of the display.
Most displays are basically not IP-rated for water. Then there are displays that have IP56 rating for the front panel, which is kind of unclear as naturally the screen area can stand water, but what is considered a front panel? Clearly the vent grooves and connectors on the back cannot handle water. Then there are monitors with IP67 or IP68 ratings. Those are much more expensive and also much more bulky by design. More about IP-ratings in Wikipedia.
Some US products use NEMA-classification. You can find more about NEMA-types in Wikipedia.
A large high brightness monitor can consume 35W of power. It also produces heat. You should take that into account when selecting a monitor. It may also be that the monitor cannot be situated in a direct sunlight because of the possibility of overheating.
Marine capable high brightness monitors, displays and panels
All the monitors listed below are high brightness, but some of them may not be usable outdoors in direct sunlight. I have also included a link to where you can buy the product. However, the supplier may not deliver to all locations. Based on the old saying “If you’ll need to ask, you cannot afford it”, I have left out the monitors that there was no pricing available (seriously speaking, typically when there is no price, the monitor is not sold directly to consumers).
Non-waterproof (enclosure not fully IP-rated)
This section includes all monitors that do not have an enclosure that is fully IP rated as the front panel rating does not really matter in itself if the monitor is used outdoors. The front panel IP rating may be useful if the monitor can be mounted into the steering console, so that water will not get to the backside of the monitor.
Small field monitors (non-touchscreen)
If you need a small and bright display, but do not need a touchscreen, you can use a (camera) field monitor. They are very bright, but not cheap, considering their small size.
Other non-touch screen monitors
Many of the monitors are available optionally with our without touchscreen. The ones listed in this section are only available without a touchscreen.
Touch screen sunlight readable monitors
|Ennox||15.6″||1500 nits||1366×768||res, cap||$610|
|Ennox||15″||1500 nits||1024×768||res, cap||$560|
|Ennox||17″||1500 nits||1280×1024||res, cap||$770|
|Ennox||19″||1500 nits||1280×1024||res, cap||$800|
|Ennox||19″||1500 nits||1440×900||res, cap||$800|
|Ennox||21.5″||1000 nits||1920×1080||res, cap||$1000|
|MoniServ||19″||1200 nits||1440 X 900||res||$740|
Display panels and open frame monitors
If you want to do the enclosure yourself, there is an option to use display panels (components) or open frame monitors. Some of them come assembled and you just basically connect the power and HDMI cables, but some of them you’ll need to assemble yourself by attaching the driver board to the display.
Monitors rated IP65
Faytech has several models with high brightness and IP65 rating. IP65 rating may not be enough for monitors that are stored outdoors in marine environment, but they can at least take splashes and occasional rain. The Faytech monitors also have brightness adjustment on the front panel, which is excellent. The resolution is quite modest, but 4:3 aspect ratio is great especially for 12.1″ and smaller monitors.
In Europe, Faytech monitors are available from distributors like Vasari.
Inelmatic also makes IP65 rated monitors, but they are more expensive ($1000 for 10″ monitor).
Waterproof monitors rated IP67 or IP68 (IPX7 or IPX8)
These waterproof monitors are hard to find and also very bulky (and some of them plain ugly). Here are a few examples available on Alibaba: 12″, another 12″, 15″, 15.6″. However, with the monitors sold in Alibaba, there are a few issues: first you need to check the brightness as sunlight readable does not always mean high nits value. Also, the nits value on the product page may not be the actual nits value, so you need to check that from the seller company before ordering. The same applies to the IP rating, the rating shown in Alibaba may not be the actual rating. Actually, you should verify all the specs before ordering. Another issue is that Alibaba is not basically catering for consumers, but for companies, so they may not sell you a single unit (although you can tell them that you are evaluating the unit for a new product you are developing). One additional issue are the customs fees and taxes that you will most probably have to pay when ordering directly from China. Take those into account too. For orders to US, you also need to check the FCC compliance as customs may actually prevent the import if the monitor is not FCC compliant.
There are also other suppliers for high IP rating monitors, but those are quite expensive compared to the ones above and typically out of the budget of a DIY chartplotter builder.
Xenarc offers both sunlight readable and and IP66 and IP67 high-brightness monitors, but those are over $1,000 for 12″. Argonaut supplies sunlight readable high-brightness touchscreen monitors with IP67 (or NEMA 4X) rating, but those are also well over $1,000 for larger sizes. I have included some of their models below as reference although they are pricewise outside of the scope of this post.
|Xenarc||10.1″||1200 nits||1280 x 800||cap||$800|
|Xenarc||12.1″||1200 nits||1280 x 800||cap||$1200|
|Argonaut||7″||1000 nits||800 x 480||cap||$400|
|Argonaut||10.1″||1000 nits||1280 x 800||cap||$1300|
Other suppliers for industrial monitors
Beetronics offers a selection of reasonably priced industrial monitors in sizes from 7″ to 22″. However, as the brightness of their monitors is only 400 nits (some only 300 nits), they may only be used indoors in a place where there is absolutely no direct sunlight.