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Next day delivery Black Kite altimeter - Develop-able altimeter and data logger
Named after an exquisite high flying feathered friend, our Black Kite altimeter is ready to fly straight out of the box.
What's more you can further develop or tweak the software should you choose! Although the included base software has tons of features already.
Ready to fly, straight out of the box!
If you fancy making your own altimeter or flight computer and want a basic building block then this is for you!
Likewise if you're just after a great altimeter that records tons of data for you to download over WiFi with ease later then this is also for you.
(No programming is necessary it is a working product out of the box)
The altimeter comes in a open top 3D printed box to protect the board and battery while still letting you access the altimeter if you are developing it further.
You can remove the altimeter from the case and mount it in your electronics bay if you prefer.
Dimensions and weight
While in the case the dimensions are 68.8mm overall length, 27mm at the widest point where the battery plug is, and 14.5mm maximum height.
The case is only 12mm high and 53mm long excluding the mounting holes.
The altimeter weighs in at 14.4 grams in it's case.
If you remove the altimeter from it's case then it will measure just 52.3mm length, 22.9mm width and 13.4mm in height from the base of the battery to the top of the battery connector.
The altimeter weighs just 11.1g out of it's case. 
It's a data logger too!
The altimeter is easy to use and records the last 4 flights of up to 10500 samples on each flight. Depending on the samples per second you choose this can record 4 flights of up to 10 minutes each.
The data from each flight can be downloaded from the WiFi admin panel in CSV format to either a phone, tablet, laptop or PC to create charts.
After each flight the device will show you a summary of the maximum altitude, time to apogee, and maximum velocity upwards and downwards.
You can of course look at much more information using the CSV files after the flight should you choose.
High accuracy
We let you set the local forecast pressure in the altimeter prior to launch, this allows the barometric pressure to be read incredibly accurately.
You can set this from the WiFi admin panel along with other settings as well as directly on the device when you turn it on.
The BMP280 pressure sensor is a great accurate sensor.
We tested the altimeter on a DJI drone to a GPS altitude of 120 meters, the Black Kite altimeter reported back at 120.1 meters for example.
WiFi admin panel
You can connect to the devices WiFi and then visit the page shown on your device to access data and edit more settings.
The admin panel lets you control settings such as:
Forecast pressure
You can view your local weather forecast for your launch site to find an accurate pressure to enter.
This lets the altimeter know roughly the actual altitude it is at above sea level and give a more accurate altitude reading.
Launch detect height
This setting tells the altimeter when to start recording.
The altimeter will watch for a rapid altitude change, and once it exceeds this setting it will enter record mode.
We suggest 5 or 10m as sensible options here.
Sample rate
Three options are available for the altimeters sample rate.
32 samples / second: This is the default setting and lets you record for 5 minutes at this rate.
16 samples / second: For longer flights this setting lets you record for 10 minutes.
Hybrid: This lets you record at 32 samples per second for the first minute before dropping to 16 samples / second for 9 minutes total.
Recording stop method
By default the altimeter will stop recording when the altitude no longer changes for 5-6 seconds suggesting it has landed.
You can turn this off and require the button on the altimeter to be pressed to stop the recording if needed.
There is also a QR code to scan and read the altimeters manual on another device if you need while at the launch site.
Internal Rechargeable 220mAH LiPo battery
Our altimeter has a rechargeable LiPo battery. Just plug in a USB-C cable to charge your device. (not included).
This battery gives around a 2 hour "on" time for the altimeter. Wifi mode uses twice the power so you'll only get just over an hour from full charge if you turn WiFi on.
Charging however is fast and only take an hour should you need to top up!
Development mode
Should you want to tweak how the altimeter works, customise it or turn this into a project of your own then you can.
With each purchase you will get access to the source code file for the current altimeter software.
You can use Arduino IDE software to program the Altimeter.
This altimeter is a very powerful device and can do much much more than our altimeter already does. You could make your own flight computer even.
There is a onboard STEMMA QT port making it easy to add extra sensors or output MOSFET's for example to fire electronic igniters, or control servos (a servo controller may be required).
The included code should make it easy to get the grips with the board and learn to use the ESP32-S3 chip on the altimeter.
Both Bluetooth and WiFi are present on the board.
The altimeter is ready to fly straight out of the box, you don't have to program it if you don't want to!
When you turn on your altimeter it will follow a routine as follows.
Step1: Enter the local forecast pressure.
This step requires you to enter your local forecast pressure for the time and location of your launch. This step allows the altimeter to more precisely work out it's altitudes and give you better data.
If you want to skip this step we suggest going for something around 1013mb which is the average air pressure.
Likewise you can skip this step and enter the pressure more easily via the WiFi admin panel later.
Pop over to xcweather.co.uk or the Met Office to track down your expected forecast pressure. If you're using a mobile device be sure to turn it on it's side to see the pressures with xcweather.
To change the value press the button nearest the screen in short presses to increase the value. Once it reaches 1059mb it will re-start counting at 937mb.
If you need values outside of this (which is unlikely) you can set them using the WiFi admin panel.
Once you're happy with your value then hold down this button for 2.5 seconds to continue (A long press).
Step2: Calibration
You don't need to do anything here, you just need to wait for around 6 seconds.
During this time the device is busy filling it's buffer of average pressure reads with a few hundred samples.
This allows the altimeter to know where ground level is, it maintains a a minute average so if your launch pad is greatly higher or lower than where you turn the altimeter on we suggest waiting at least a minute before launch, or turn the device off and back on again once at the launch pad.
Step3: Ready to launch
Your device is now ready to launch, and should tell you this. It will keep a pre-buffer of samples so that no data is missing once the rocket reaches it's triggering altitude.
A fully charged battery should last around 3 to 5 hours in this state.
The screen will show you the following information:
LD: Launch detect, this shows you the altitude the device is seeing on it's last sample compared the the 1 minute average. The altimeter uses this to work out if the launch detect altitude has been reached to trigger recording.
SPS: It will show you the actual samples per second and the setting for the samples requested on the ready screen.
You can now either launch your rocket, or press the button again for a long press to enter WiFi mode.
Step4: Wifi mode
Should you wish to edit any settings, download data, or view more information you can enter WiFi mode by pressing the button for a long press from Step 3.
Once WiFi mode is on you can connect your Phone, Tablet, Laptop or PC to the devices WiFi.
By default the device will call it's Access point MRS_Altimeter_XXXX (XXXX will be 4 random digits).
Once connected your device will probably tell you there is no internet, tell it that's OK and then load your web browser.
Visit the web page http://192.168.0.1 (You may need to type the http:// in some browsers to get it to work).
You can now download flight logs, flight text files, and adjust your altimeters settings.
You can click the question marks by each setting for a little information about what each one does. There is more details information in these instructions further down too if required.
To return to Step3 and be ready for launch press the button for a long press again. This will turn off WiFi and return to the calibration step.
WARNING: WiFi mode uses quite a lot of power, ideally leave your device plugged into a USB C cable while using WiFi. Although you can run it without and your device will last for around 1 to 1.5 hours from a full charge in WiFi mode.
Step5: Flight
Once you've launched your rocket, the altimeter will start to record once the altitude exceeds the launch detect value.
It will add the pre-recording buffer to the samples and look back to when the rocket started to leave ground level for the launch time.
Depending on the samples per second option you picked your altimeter can record for 5, 9 or 10 minutes maximum.
With the default flight end detection enabled the rocket will stop recording when the altitude is no longer changing for at least 5 seconds.
You can turn this off and require the button to be pressed to stop recording should you choose.
After the flight the altimeter will display a few details from your flight.
From here you can either enter WiFi mode to download the flight data, or turn the device off and back on to fly again.
Please note that if you enter WiFi mode you can then leave WiFi mode back to the launch screen without turning the device off and back on.
You can create great charts in spreadsheet software or work out lots of extra flight information from this data.
The altimeter does not have WiFi on by default as it uses a lot of power. It is however quite easy to access WiFi mode.
Turn on your altimeter by pressing the on/off button. You will be asked for air pressure forecast information next, you can just hold down the button to skip this if you're entering WiFi mode.
You can enter the pressure in WiFi mode more easily anyway.
Once the unit is calibrated you will be shown the ready to launch screen. From here just hold down the button nearest the screen for 2.5 seconds to enter WiFi mode.
Once WiFi mode is on you can connect your Phone, Tablet, Laptop or PC to the devices WiFi.
By default the device will call it's Access point MRS_Altimeter_XXXX (XXXX will be 4 random digits).
Once connected your device will probably tell you there is no internet, tell it that's OK and then load your web browser.
Visit the web page http://192.168.0.1 (You may need to type the http:// in some browsers to get it to work).
You can now download flight logs, flight text files, and adjust your altimeters settings.
You can click the question marks by each setting for a little information about what each one does. There is more details information in these instructions further down too if required.
To return to Step3 and be ready for launch press the button for a long press again. This will turn off WiFi and return to the calibration step.
WARNING: WiFi mode uses quite a lot of power, ideally leave your device plugged into a USB C cable while using WiFi. Although you can run it without and your device will last for around 1 to 1.5 hours from a full charge in WiFi mode.
The first file is a CSV file which can be imported to spreadsheets with all of the flight data. The second file is a text file with some of the flight details for each flight such as Maximum altitude, Velocity and the time to Apogee.
The CSV file contains the time in ms from launch, the altitude, the approximate velocity, each axis acceleration data and the overall acceleration. There will be a line for each sample at the chosen samples per second rate.
You can download these files from the web interface using WiFi mode.
The altimeter only stores the last 4 flights of up to 10500 samples per flight.
The board is based on a ESP32-S3 microcontroler which is a very powerful chip for a altimeter. You can adjust the code or even re-program the device entirely and add extra sensors, outputs, servos and more.
You can download the current software in a zip file from our website attached to your order if you want to use this as a building block to help get you started. The current software is for use with Arduino's IDE software which is free.
Steps to enter programming mode.
1. Download and install the Arduino IDE software.
2. Connect your device to your computer with a USB C cable.
3. Hold down the button nearest the screen on the altimeter (BOOT), and then press and release the Reset button (RST). This will put the device in boot mode and it can then be programmed.
4. Select your board in the Arduino IDE software using the drop down at the top left of the software.
5. Pick select other board and port.
6. Under BOARDS select Adafruit Feather ESP32-S3 TFT (this isn't an Adafruit board even though they are awesome! However it's similar so this board selection works well for programming it).
7. Click OK and you're ready to go!
You can now load this up and edit it / upload it to your device.
You will need to install some required libraries, these are all listed at the top of our software. To install them just click on Tools at the top, and then on Manage Libraries.
You can now search for each one and install them. Some will already be internal parts of Arduino IDE so there should only be around 8 libraries to install.
The current program has lots of notes added to it to help you understand how it works as you scroll through.
Suggestions.
Under tools -> Partition scheme -> Check this is set to No OTA (2MB APP / 2MB SPIFFS)
This gives 2MB of space to the file system and 2MB for the APP. The current program (APP) is around 1.1MB so this will leave you plenty of space for expansion.
POWER: The altimeter board has a USB-C port to charge the device and power it. There is also a JST PH 2.0 connector for connecting the battery to, you can connect any LiPo 220mAh or larger to this port but please ensure your battery has the correct polarity, or you may end up destroying your board! The onboard regulator can supply up to 500mA of current at 3.3v
TFT DISPLAY: The board has a 1.14" TFT with 240 x 135 pixels.
BATTERY MONITORING: This board does not have a dedicated monitoring chip, however your board has a 1:1 ratio voltage divider connected to analog pin A1 from the battery to the pin to ground. This allows you to monitor the battery voltage using the ESP's ADC.
