Difference between revisions of "LightPi"
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| − | </div><div>Finding a source for the Raspberry Pis should not be difficult, as big electronics resellers (e.g. RS Components) have them listed. Usually the A/A+ models (and their cases) are harder to find, and the Zeros tend to be outsold.</div><div><br/></div><div>A suitable RTC module can be found here: [https://www.aliexpress.com/item/Free-shipping-1PCS-DS3231-Real-Time-Clock-Module-forarduino-3-3V-5V-with-battery-For-Raspberry/32570116150.html [1]]</div> | + | </div><div>Finding a source for the Raspberry Pis should not be difficult, as big electronics resellers (e.g. RS Components) have them listed. Usually the A/A+ models (and their cases) are harder to find, and the Zeros tend to be outsold.</div><div><br/></div><div>A suitable RTC module can be found here: [https://www.aliexpress.com/item/Free-shipping-1PCS-DS3231-Real-Time-Clock-Module-forarduino-3-3V-5V-with-battery-For-Raspberry/32570116150.html [1]]</div><div><br/></div> |
| + | === Choosing a Raspberry Pi model === | ||
| + | <div>Some hints regarding the different models:</div> | ||
| + | *All "B" models have 2+ USB ports, eliminating the need for an USB hub. | ||
| + | *Also, all "B" models come with an Ethernet port, the A/A+/Zero models do not have native networking capabilities. | ||
| + | *Model 3 B even has it's own onboard WiFi adapter. | ||
| + | *The Models A+/Zero have the lowest power consumption - ideal for off-grid stations. | ||
| + | *Model Zero has no fullsized USB port, thus needing an USB-OTG adapter. | ||
| + | *First generation RasPis (1A and 1B, or just "A and "B") use full size SD cards, other models use MicroSD. | ||
| + | *Used first/second generation RasPis can be found very cheap on the internet. | ||
| + | <div> </div><div>The bottomline is:<br/></div> | ||
| + | *Minimum Energy consumption: A+/Zero | ||
| + | *Maximum Networking: Model 3 B | ||
| + | <div> </div><div><br/></div> | ||
| | ||
Revision as of 03:01, 17 November 2016
oooooooooo This article is under construction! oooooooooo
Contents
Introduction
The Lightrouter
Up to now, the Lightrouter was our preferred workhorse for collecting and transmitting Lightmeter data. It's low-cost and low-power design allowed for continuous nightsky measurements, automatic data transmission and even - to some extent - remote maintenance.
But, over time several issues surfaced:
- The hardware version 2 of the WR1043ND rendered our firmware image obsolete, leading to a more manual setup routine.
- Future hardware versions will come with a locked firmware, preventing the use of OpenWRT (due to a new FCC rule).
- In offline-scenarios (no NTP, and no GPS) the internal clock performed terrible, exhibiting nonlinear, irregular drifts.
- The internal flash memory is not large enough to hold the entire setup, leading to the need of an overlay filesystem, creating a high dependency on the presence of the USB stick.
- Due to ill-defined brown-out behaviour of the router, the filesystem of several USB sticks got corrupted, leaving the stations paralyzed.
- Our central server died (summer 2016), leaving the reverse-SSH-tunnels dangling in mid-air, and thus preventing remote connections and data collection.
- Power consumption with up to 18W is too much for solar powered off-grid stations.
- Some gerneral reliability issues.
The LightPi
To combat all these shortcomings, the LightPi is under development. Based on a Raspberry Pi, extended by a realtime module, the LightPi will be easier to set up and to maintain, without increasing the price tag.
Some of it's main features are:
- High and reliable hardware availability, good inter-generation compatibility.
- Higher computing power and full debian-based operating system.
- Lower power consumption (2-4W [Model 3 B], 0.5-1.2W [Model A+]). *
- 4 USB ports (Model B+ upwards), eliminating the USB hub.
- SD-card instead of small onboard flash - no more overlay filesystems.
- Highly accurate DS3231 RTC module (+/-3.5ppm).
- Simple plug-and-play with any FAT32 formatted USB stick for data storage.
- As inexpensive as the Lightrouter.
*...based on interpolation of various internet sources.
As the LightPi platform ist still under active development, several features are not yet implemented:
- Remote shell access (partly implemented).
- Data transmission/collection (planned).
- NTP synchronsiation (planned).
- GPS synchronisation (planned).
- On-site network service for data access (planned).
- Independence of a central server infrastructure (design guideline).
Current state
The LightPi project's current state is developing / testing .
All the key networking capabilities have yet to be implemented, but the offline version is already up and running. First long-term reliability tests are currently in their starting phase.
Hardware acquisition
LightPi shopping list
- Raspberry Pi (any model)
- DS3231 RTC module
- MicroSD / SD card (dep. on RasPi model) with 4+GB
- Power supply (5V, micro USB)
- USB stick (FAT32 formatted)
- For model A/A+/Zero USB hub
- For model Zero: USB-OTG adapter
- Optional, but recommended: A case for the RasPi
Finding a source for the Raspberry Pis should not be difficult, as big electronics resellers (e.g. RS Components) have them listed. Usually the A/A+ models (and their cases) are harder to find, and the Zeros tend to be outsold.
A suitable RTC module can be found here: [1]
Choosing a Raspberry Pi model
Some hints regarding the different models:
- All "B" models have 2+ USB ports, eliminating the need for an USB hub.
- Also, all "B" models come with an Ethernet port, the A/A+/Zero models do not have native networking capabilities.
- Model 3 B even has it's own onboard WiFi adapter.
- The Models A+/Zero have the lowest power consumption - ideal for off-grid stations.
- Model Zero has no fullsized USB port, thus needing an USB-OTG adapter.
- First generation RasPis (1A and 1B, or just "A and "B") use full size SD cards, other models use MicroSD.
- Used first/second generation RasPis can be found very cheap on the internet.
The bottomline is:
- Minimum Energy consumption: A+/Zero
- Maximum Networking: Model 3 B
Setup
Preparation
Hardware
For the setup process you need:
- Your computer
- SD/MicroSD card reader
- HDMI capable monitor
- HDMI cable
- USB mouse
- USB keyboard
(The USB/HDMI items may be borrowed from your computer - no need for a second set.)
Optional, but highly recommended for the setup process:
- Internet connection via WiFi
- USB WiFi adapter (for all models except 3 B)
or:
- Internet connection via Ethernet
- USB Ethernet adapter (for models A/A+/Zero)
Software
- The Raspbian image file from https://www.raspberrypi.org/downloads/raspbian/
- If you are using Windows: Win32DiskImager
LightPi zip archives
Always use the most recent version!
v20161115
First public version of LightPi.
Instructions inside.
Configuration
 |
| Raspberry Pi Model 3 B (left) and Model A+ (right), outfitted with a DS3231 RTC module (a third one on the bottom right). |
...
