0 With this firmware, you can use an ESP8266 WiFi module for telemetry icw an UAS that runs Paparazzi autopilot code. To connect there are two option. The first is that the module can work as a client that connects to a Hotspot. For example, you can have the ESP module connect to the a same router as your computer. The second option is to set it up as a Router itself, then just connect your groundstation PC to this module.
To make the modification one nees some 0402 SMD components:
- 5x 4k7 Resistor
- 1x 1k Resistor
Optionally: To give a hint about the status of the ESP and the data a LED comes in handy
- 1x Blue LED (Farnell ?)
Voltage regulator can be added if one wants to power the ESP in a more risk free way
- 1x Voltage regulator (Farnell ?)
TPS70933DBVT Fixed LDO Voltage Regulator, 2.7V to 30V, 960mV Dropout, 3.3Vout, 150mAout, SOT-23-5
To create the module just buy a regular ESP09 module, available from many suppliers. Add (kapton) tape in the middle of the bottom of the module. It is the yellowishbrown square in the middle of the PCB. Prevents shorting on the four ground pads. Us skill and patience and solder the resistors and LED and I/O wires.
There is also an very light and minimum sized Pico-ESP, developed at the MAVLab TUDelft. This module runs the very same software.
Installationthe following:
- Download the latest stable Arduino IDE from the Arduino website. We used the Linux 64 version with good success.
- Enter
http://arduino.esp8266.com/stable/package_esp8266com_index.jsoninto Additional Board Manager URLs field. You can add multiple URLs, separating them with commas. You can find it under menu item File -> Preferences -> Settings - Open Boards Manager from Tools -> Board menu and install esp8266 platform.
Configuring the ESP
- Within the Arduino IDE, select your ESP8266 board from Tools -> Board menu.
- Open
pprz_udp_link.ino. There should also be a tab withwifi_config.h. - In
wifi_config.h, configure the settings of the hotspot you want to connect to. - Also change the broadcastIP to the broadcast IP in your network. In Linux, you should be able to discover this by executing
ifconfig. Look forBcast:*.*.*.*for the wireless network interface (something like wlan*).
Basically:
- Upload the firmware to your ESP8266 by pressing the upload button.
But it needs to be in bootloader mode.. You have to connect GND with GPIO0 while applying power!
The very first time, or if things are screwed up, the firmware needs to be flashed to the pico-esp using UART. Use a 3.3V USB-to-Serial cable and connect Tx->Rx, Rx->Tx, Gnd->Gnd.
It is usually better to use an external power source for the 3.3V. The 3.3V USB-to-Serial cables have only 3.3V on Rx and Tx, the VCC is still 5V from USB which will damage your ESP
To get the pico-esp in boot-mode, you have to connect GND with GPIO0 while applying power. GPIO0 has no pin on the pico-esp, but just a very small patch at one corner.
When the Pico-ESP is in boot mode, the firmware can be flashed from the Arduino-IDE. See README.md for instructions on getting the IDE. Use the following configuration for flashing.
Sometimes an flightcontrolle board does not have enought IO pins left. To still be able to use more sensor the IO of the IO pins of the ESP8266 can be used. Then one is still able to read the sensor data. Data from these sensors will be injected into the regular datastream on PPRZlink going to FC. For this one has to enable the sensor in the setting file.
The current code supports a magnetometer or a ranging sensor. It is possible to add different sensors, one has to add support to the code.
Lots of sensors have an I2C bus for IO. This will be used. Connect GND, VCC to respective ports on PCB and connect SCA of sensor to GPIO2 and SCL to GPIO4 of main PCB
The firmware can be updated over WiFi. This should performed with care!. It is crucial to configure the WiFi correctly in the new firmware, otherwise you will not be able to establish a connection with the ESP and you will need to reprogram it over UART.
To update over the air, first you need a firmware image. In the Arduino-IDE, this can be generated from the menu Sketch->Export compiled Binary. This generates a binary image in the folder of the sketch.
In Client mode, the Pico-ESP connects to a router. If your computer is connected to the same network, you can upload the firmware with the following command. This command contains the link to the espota.py tool which is part of the ESP Arduino package. The directory might be different on your system. Also update the path to the binary.
python ~/.arduino15/packages/esp8266/hardware/esp8266/2.1.0/tools/espota.py -i esp-module.local -r -f ~/git/esp8266_udp_firmware/pprz_udp_link/pprz_udp_link.cpp.generic.bin
If you have configured the Pico-ESP in AccesPoint mode, you can connect to the pico-esp with a laptop. The command is slightly different, since it now contains the IP of the module:
python ~/.arduino15/packages/esp8266/hardware/esp8266/2.1.0/tools/espota.py -i 192.168.4.1 -r -f ~/git/esp8266_udp_firmware/pprz_udp_link/pprz_udp_link.cpp.generic.bin
In your airframe file, put the following configuration within the main AP<firmware> section:
<subsystem name="telemetry" type="transparent">
<configure name="MODEM_BAUD" value="B115200"/>
<configure name="MODEM_PORT" value="UART1"/>
</subsystem>
If you are using a different serial port on you autopilot board, change UART1 accordingly.
WARNING: The module runs on 3.3V, don't put 5V on it, 5V will destroy you board
To connect the module to your AP board:
- Connect VCC and GND, RX to TX, and TX to RX of the ESP09 board
| ESP8266 | Autopilot |
|---|---|
| VCC | 3.3V |
| GND | GND |
| RX | TX |
| TX | RX |
- Connect to you SSID of the module or let it connect to your router
- Start Paparazzi Center
- Select Tools -> Data Link
- Stop link
- Replace the command line options with "~/paparazzi/sw/ground_segment/tmtc/link -udp".
- Press [REDO] to restart link with the new parameters
- Wait a second...
- Enjoy telemetry over Wifi with Paparazzi
TIP: Data Messages can be simply viewed also with the.. message tool, see the Paparazzi Center tools menu.
Well, yes it is a opensource wiki and project. If you feel something is lacking, please add it, TIA
Instead of flashing the module with a fixed SSID and password, it would be nice to have this configurable from the autopilot. Upon startup, the ESP8266 could send out requests for the SSID and password. A module within PPRZ could react by providing this in a PPRZ message format.
If the tiny flash chip does not have enough storage for your gusto,this 2MB is compatible with the ESP8266. Not needed for this project, but if you are building your own, a nice alternative.
For more information also take a look at
- This ESP8266 SDK project on github
- Information about the ESP8266 chip and arduino tools: esp8266 wiki