RAK Hotspot Datasheet
Overview​
Description​
Hotspot Details
- Efficient for a new cryptocurrency, Helium (HNT)
- Complete set-up in minutes using a smartphone
- LongFi technology maximizes range and battery life without Wi-Fi, cellular or Bluetooth
- Low Power – only uses about the same amount as an LED light bulb (5 W)
- Easily manage Hotspots and tokens from the mobile app
- LongFiâ„¢ Technology
Helium LongFi is a technology architecture that combines a leading wireless technology, LoRaWAN, and the Helium Blockchain. LongFi is optimized for miles of range, and long battery life for IoT devices.
RAK Hotspot earns Helium when devices connect, and for validating wireless coverage delivered by peers. Using a system called Proof-of-Coverage, RAK Hotspot earns more Helium when they're in range of other RAK Hotspot, but need to be at least 300 meters apart.
Range depends on the environment, for rural areas up to 10 miles or more, but for more dense areas up to a mile. Single RAK Hotspot earns less as they can only issue Challenges over the internet, and can’t participate in Proof-of-Coverage.
- Deliver many square miles of coverage from a single RAK Hotspot
- Based on initial testing, only about 50 to 100 RAK Hotspots are needed to provide complete coverage for an entire city
- Create a new global network for billions of devices
- Any IoT device can become Helium-enabled using readily available off-the-shelf hardware components, software, and a reference design that is open source for anyone to improve upon
Features​
- Computing with Raspberry Pi4 (Linux)
- 2Â GB on-board RAM
- 32Â GB SD card
- Based on the LoRa Concentrator Engine: Semtech® SX1302
- Built-in Heat Sink for thermal heat dissipation management
- Supports 5Â V/ 3Â A power supply
- IP30 housing
- TX power up to 27Â dBm, RX sensitivity down to -139Â dBm @SF12, BW 125Â kHz
- LoRa Frequency band support: RU864, IN865, EU868, US915, AU915, KR920, AS923.
- Includes Pi ready 'ID EE PROM', GPIO setup, and device tree can be automatically configured from vendor information
- Supports a fully open source LoRaWAN server
Specifications​
Overview​
The overview covers the RAK Hotspot hotspot details and block diagram.
Board Overview​
The outer dimension of RAK Hotspot is 92 x 68.3 x 57.2Â mm.
Hotspot Details​
The figure below summarizes the basic building blocks of the RAK Hotspot. The RAK2287 is an essential part of it as it provides all LoRaWAN connectivity. It receives and transmits LoRa Frames and takes care of modulating/demodulating the signals among others. The processing of the LoRa Frames as well as higher-level protocol related tasks are done by the embedded host system (Raspberry Pi). Received and processed LoRa Frames are being sent to a LoRaWAN Server. The segmentation of protocol related tasks is outside the scope of this document.
Block Diagram​
The RAK Hotspot is the central hardware solution for all LoRa based radio communication. It receives and transmits radio messages. The processing of radio messages as well as the protocol related tasks are done by the embedded host system (Raspberry Pi 4). Received and processed radio messages are being sent to a LoRaWAN server. The following figure shows the block diagram of the RAK Hotspot.
The concrete segmentation of the protocol related tasks is outside the scope of this document.
Hardware​
Interfaces​
The interface of RAK Hotspot is shown in the figure below.
RF Characteristics​
Operating Frequencies​
The RAK Hotspot supports all LoRaWAN frequency channels as below. It is easy to configure while building the firmware from the source code.
| Region | Frequency (MHz) |
|---|---|
| Europe | EU868 |
| North America | US915 |
| Asia | AS923 |
| Australia | AU915 |
| Korea | KR920 |
| India | IN865 |
| Russia | RU864 |
LoRa RF Characteristics​
Transmitter RF Characteristics​
The RAK Hotspot has an excellent transmitter performance. It is highly recommended to use an optimized configuration for the power level configuration, which is part of the HAL. This results in a mean RF output power level and current consumption.
| PA Control | PWID Control | Power |
|---|---|---|
| 0 | 10 | -6Â dBm |
| 0 | 13 | -3Â dBm |
| 0 | 17 | 0Â dBm |
| 0 | 20 | 4Â dBm |
| 1 | 0 | 8Â dBm |
| 1 | 2 | 10Â dBm |
| 1 | 4 | 12Â dBm |
| 1 | 7 | 14Â dBm |
| 1 | 9 | 16Â dBm |
| 1 | 10 | 17Â dBm |
| 1 | 12 | 19Â dBm |
| 1 | 13 | 20Â dBm |
| 1 | 16 | 23Â dBm |
| 1 | 18 | 25Â dBm |
| 1 | 20 | 26Â dBm |
| 1 | 22 | 27Â dBm |
Normally, there is a ±1.5 dB difference between the actual test value and the table data.
T=25 ℃, VDD=5 V (Typ.) if nothing else is stated.
| Parameter | Condition | Min | Typ. | Max |
|---|---|---|---|---|
| Frequency Range | 863Â MHz | 870Â MHz | ||
| Modulation Techniques | FSK/LoRa | |||
| TX Frequency Variation vs. Temperature | Power Level Setting : 20 | -3Â kHz | +3Â kHz | |
| TX Power Variation vs. Temperature | Power Level Setting : 20 | -5Â dBm | +5Â dBm | |
| TX Power Variation | -1.5Â dBm | +1.5Â dBm |
| Parameter | Condition | Min | Typ. | Max |
|---|---|---|---|---|
| Frequency Range | 902Â MHz | 928Â MHz | ||
| Modulation Techniques | FSK/LoRa |
Receiver RF Characteristics​
It is highly recommended, to use optimized RSSI calibration values, which is part of the HAL v3.l. For both, Radio 1 and 2, the RSSI-Offset should be set at -169.0. The following table gives the typical sensitivity level of the RAK Hotspot.
| Signal Bandwidth (Khz) | Spreading Factor | Sensitivity (dBm) |
|---|---|---|
| 125 | 12 | -139 |
| 125 | 7 | -125 |
| 250 | 12 | -136 |
| 250 | 7 | -123 |
| 500 | 12 | -134 |
| 500 | 7 | -120 |
Antenna Specifications​
LoRa Antenna​
Overview​
The LoRa Antenna with RP-SMA Male connector is shown in the figure below:
Antenna Dimension​
The antenna's mechanical dimension is shown below:
Antenna Parameters​
| Items | Specifications | Specifications |
|---|---|---|
| Frequency Range | 863~870Â MHz | 902~928Â MHz |
| Peak Gain | 2.8Â dBi | 2.3Â dBi |
| Voltage Standard Wave Ratio (VSWR) | ≤1.5 | ≤1.5 |
| Efficiency | >80% | >80% |
| Feed Impedance | 50 Ohms | 50 Ohms |
| Working Temperature & Humidity | T: -35~+75 ºC, H: 5~95% | T: -35~+75 ºC, H: 5~95% |
Electrical Requirements​
The RAK Hotspot operates at 5Â V/ 3Â A
| Parameter | Min. | Typical | Max |
|---|---|---|---|
| LoRa Tx mode | - | - | 950Â mA |
| Standby power | - | 550Â mA | - |
| Burn test mode | - | - | 940Â mA |
- LoRa Tx mode: The LoRa module works at the maximum transmit power state.
- Burn test mode: Raspberry Pi CPU and memory are running at full capacity.
Environmental Requirements​
The table below lists the operation and storage temperature requirements:
| Parameter | Min. | Typical | Max |
|---|---|---|---|
| Operation Temperature Range | -10 ºC | +25 ºC | +55 ºC |
| Storage Temperature Range | -40 ºC | +85 ºC |
Firmware​
| Model | Raspberry Pi Board | Firmware Version | Source |
|---|---|---|---|
| RAK Hotspot | Raspberry Pi 4 |
Software​
LoRaWAN​
- Supports class A, C
- Supports connect to TTN server Supports LoRa package forward
- Supports build-in ChirpStack® LoRaWAN Server
Network Protocol Stack​
- Supports 802.11ac
- Supports Wi-Fi AP mode and Client mode
- Supports DHCP
FCC Caution​
Any changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment.
This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.
This equipment has been tested and found to comply with the limits for a Class B digital device, according to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used following the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and receiver.
- Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
- Consult the dealer or an experienced radio/TV technician for help.
FCC Radiation Exposure Statement​
This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment. This equipment should be installed and operated with a minimum distance of 20Â cm between the radiator & your body.
This device complies with Innovation, Science, and Economic Development Canada licence-exempt RSS standard(s). Operation is subject to the following two conditions:
- this device may not cause interference, and
- this device must accept any interference, including interference that may cause undesired operation of the device.
The device complies with RF exposure guidelines, users can obtain Canadian information on RF exposure and compliance. The minimum distance from the body to use the device is 20Â cm.
