2019-05-23, 07:41 AM
(2019-05-22, 07:00 PM)Didier B Wrote: Hi Didier,
thanks for your comment.
After assembling my 1st configuration in a standard vented project box, I came to the config below which I think a fair balanced approach :
Multimedia : I agree with Jim321 than video, requiring huge disk and large screen and related high power consumption should be supported by different system, but Music is part of the navigation, and I put a few GB of mp3 on the SSD, using VLC and the Bluetooth to send to a speaker, works like a charm !
- PC unit : of course an openplotter distribution on a Pi 3B+,
- Enclosure : Pi desktop, a classy, WIFI and Bluetooth friendly (made of resin), not waterproof to avoid any condensation issue, and leave a way out to humidity and excessive heat. My experience is that alu cases are no problem. I use them in different enviroments also industrie. You have roaund about 5-10% less of Wlan Power. I think in a boat this is no problem. The benefit in a alucase is that you do not need a ventilation. I usually use big cases and there is no problem
- Micro fan for heat extraction :
- SSD mSATA 128 GB (SSD is a Pi desktop feature) ; As I discriped above. I leave space in the case for this.
- secure on/off button, (Pi desktop feature) ; I think you mean the "Power" Button? See in the Picture. I have planed this as an 8-28V In. High= On, Low= Pi shuts down and cut connection when down.
- NO SD CARD ;
Note : at 55€, Pi Desktop is not a low cost enclosure, but consider the bunch of offered features : (SSD support, secure on/off switch, absence of SD card, free room to acomodate fan, power supply and compass).
- Strong supply, step down 8..36V to 5.24V (USB limit being 5.25V !), 5A, protected by a Schottky diode against reversed polarity, fits in Pi desktop enclosure ; At the moment I use a MP1593. 3A normal. I calibrate them to 5,15V until now I have never problems with that. Why so higth? You think 8-28V range is not enough? Should I expand this?
- GY91 module as barometer (BME280) and IMU (MPU9250), installed in Pi desktop enclosure ; First my plan was to do this. But after the comment of abarrow I have change. I have ready a Firmware for my W-Lan Sensor (GeCoS-W-TH). This is a BME280 with a ESP. Until now it also sends NMEA UDP (Pressure, Temp, hum). I think its better becouse you can use it in a better enviroment. It also works with 8-28V
- All Internal data and fan connections by wire wrapping (fast, very reliable and quite reversible technique, perfect for prototyping and small series) ; My english is not so good ;-) I dont understand what you mean with this point?
- AIS : by SDR via a powered USB HUB, but now many DSC VHF offers that function, using a single antenna, and connected via an RS422/USB adapter ; Yes, but the most AIS reciever also use NMEA0183/2000?
- GNSS : via a cheap, small, dual USB module, offering both GPS and GLONASS ; easily replaced when more players will turn around the planet (Galileo, Beidou) :
- Boat NMEA0183 (1st gen.) : via a DB9 RS232 USB adapter;
- Everything fits in the box, or is connected via USB ...
I think I have wrong expressed: I have no Monitor on this Pi. I use it as a bluetooth reciever (The boxes on the Pi) so I can stream the Music from my phone or tablett. And I have internetradio on this pi wich I can controll from my phone.
What I will always favor : a small 11 x 11 x 5 cm enclosure, a single VHF antenna, lowest possible power consumption, ease of use of the USB ...