I & Nick Arsov are proud to introduce our newest product,
Airbotservices has been passionate at understanding and documenting ways to power flight controllers to ensure redundancy and maximum reliability, especially in conditions where a 4S 3DR power module (or similar PM) can’t be used: battery voltage above 4S and currents above 90 amps. Historically we published how-to guides on this topic, contributed writing documentation in the wiki and on the PX4 autopilot site:
We’ve got feedback from some who are not at ease nor have the necessary engineering skills to mess around with soldering individual electronics components, cables and connector adapters. We therefore think there is a need for proposing a high quality reliable plug and play “Power & Measure” solution, working also for higher voltages than 4S batteries.
AirbotPower solves the problem of powering a UAV and measuring current & voltage in a most high quality, reliable, redundant and efficient manner (extreme low voltage ripples, low noise, low EMI, MHz switching frequency). It supports battery input voltages from 3S to 8S. It supports current flows up to 150 Amps. Accessorily, we provide also an AirbotPDB board (power distribution board) :
AirbotPDB is a companion stackable board (via XT150 connectors) for those who need a power distribution board. AirbotPower can be used standalone, without a stacked AirbotPDB board, to equip or retrofit (upgrade) a drone that already has its own PDB.
AirbotPower works to power any flight controller & FPV systems by providing triple power feeds: 2x 5.3V & 1x 12V (up to 3.5 amps each). In particular, AirbotPower has been designed with Pixhawk in mind: from electronics, to voltage levels and connectors for a direct plug to Pixhawk using “off-the-shelve” servo cable and a DF13 6position cable eliminating any painstaking efforts with soldering, hacking connectors and cables.
With AirbotPower base board, comes an extra safety electronic module that plugs on Pixhawk’s servo rail: the famous Zener Diode 5.6V (5W) + capacitor. This safety module is required on Pixhawk's servo rail to trim any short voltage spikes (above 5.6V) that would be fed back to Pixhawk's servo rail from external devices & servos, which would cause Pixhawk to shutdown itself (electrical protection).
To illustrate, as concretely as possible, what AirbotPower advantages brings to your drone setup, let’s consider which individual electrical and electronic components would be required, without AirbotPower, to optimally power a flight controller such as a Pixhawk board, while being able to measure currents up to 150 amps and supporting high voltage batteries (more than 4S) : It is a complex setup requiring the assembly and interconnections of more than a dozen of components plus messing with cables that need to be hacked, soldered, etc.. This is illustrated in figure3 below:
Figure 3: complexity of components and cabling to power a Pixhawk board without AirbotPower
In addition, a notorious issue is current measurement and getting stable readings. It has always been unreliable and difficult due to limitations and fragility of the main solutions that were available until now on the market : either a typical power module including current & voltage measurement (limited to 4S and 90 amps) or adding any other external INA169 chip based current measurement products (very fragile ; INA169 chip are damaged very easily by heat when soldering wires), which are producing high fluctuation measurements as soon as you have a bit of inductance or capacitance components on its output.
On figure 3, we can observe the following issues & risks:
In comparison, figure 4 below shows what the situation becomes instead when using AirbotPower. It is obviously cleaner without the need for individual components soldering and messy cabling. A Pixhawk flight controller is powered with redundancy, with clean power feeds, with protection against servo rail voltage spikes, with 150 amps Hall effect current measurement, with dip-switch configurable 3S to 8S voltage measurements:
Figure 4: simplicity to power a Pixhawk board with AirbotPower
AirbotPower technical specifications highlights:
• Top quality & reliable components
• Provides ultra-smooth power sources; actually they are currently the least noisy you can find on the market. We actually reached the sensitivity limits of our oscilloscope as illustrated below:
Figure5: shows voltage ripples under a 5amps load is less than 6mv !
Figure 6: AirbotPower with XT150 connectors to stack AirbotPDB
Figure 7: AirbotPower with simulated XT150 parallel battery inputs
Detailed technical specifications:LT8610A/LT8610AB series DC-DC bucks FEATURES DESCRIPTION :
ACS758 CURRENT MEASUREMENT INTEGRATED IC :
A few practical guidelines!
1. Don't use servos on the backup AUX 5.3V supply as they can supply just a few amps and too many servos might exceed this amperage;
2. At least one of the DIP switch switches MUST be switched ON towards the ON mark (or towards the battery number marks); In the first batch of boards, DIP switches labels have been printed in reverse order : 3S, 4S,...,7S, 8S should instead be read reversely 8S, 7S? ...4S, 3S. Later batches will have their labels printed in the correct order.
3. On the bottom of the Power Board, there are some gold plated traces between the sensor and the 7mm holes and between BAT- and the PDB- . It is advised to add some solder on them for extreme currents. To do this you'll need at least a 80W soldering iron and must use good solder with 2-2.5% non-corrosive flux. Higher power soldering iron leads to shorter heating time which is better for both the PCB itself and the components.
4.Calibrate your current and voltage readings for absolute precision measurements. In addition, the output of the ACS758 current sensor produces a voltage of +0,6V (offset)+20mV/A (i.e. set APM:Copter parameter “BATT_AMP_OFFSET” to a value of 0,6).
To calibrate current & voltage measurements, follow the APM wiki procedure here: http://copter.ardupilot.com/wiki/common-measuring-battery-voltage-a...
Start, in Mission planner, with a "Voltage divider (calced)" value around 7,65 as shown in picture:
5. Plugging the Zener+Cap module on Pixhawk servo rail:
The module comes with a three pin standard servo connector. Only the 5V & GND wires are used. You should plug the module as shown on the picture on one of the 6 AUX ports:
Comparison of AirbotPower with other market’s typical power modules:
The board is ready for Pre-Orders:
A first small batch of AirbotPower & AirbotPDB boards have been produced mainly for early adopters and first testers.
We need help of the community to produce larger quantities. Your pre-orders will help us know what volume we need to produce and it will help us fund the production per batches. We are in the final stage of finding a reliable production partner (although we can commit on any final planning yet). We expect every batch to take between 1 or 2 months to be produced, so we will work in a rolling planning method: orders will be grouped in “periods”, FIFO (First In, First Out).
To preorder & help funding this project, please simply complete the form on this link:
This form is not an order but a preorder; it will allow me to know what must be produced and you would be billed only later on when boards are made. Please indicate on the form what’s your pack choice and wished ordered quantity. Prices is a worst case scenario defined based on small volumes. If volumes get big enough, I might be able to reduce them:
Unit price (€ ex. VAT, ex. shipping) *
Unit price (€ incl. VAT, ex. shipping) **
AirbotPower standalone (no cable / no ZenerCap module)
Pack AirbotPower+Zener/CAP module+DF13 cable
AirbotPower+AirbotPDB+Zener/CAP module+DF13 cable
(*) For Intra-European companies with a valid VAT number, no VAT will be charged.
(**) For volumes more than 10 units, please contact me for pricing.
As a final note, here a video of an airbotpower board assembled in a 6S 900mm X4 Airbotservices UAV: