New products shown at IROS

2018-10-01 | Marcus | 9 Comments

The last couple of weeks has been really intense since we’ve been busy preparing for IROS. Finally it’s here, and with it we’re releasing a few new products!

We’re excited to announce that during the fall we will be releasing the following new products:

Crazyflie 2.1: The Crazyflie 2.0 was released almost 4 years ago now. Over the years there’s been thousands of users and lots of feedback on the product. Most of it great, but there’s been a few things we’ve wanted to fix. Now with the updated 2.1 version we finally have the chance to do it. Here’s a quick list of the updates:
- Better radio performance and external antenna support: With a new radio power amplifier we’ve improved the link quality and added support for dual antennas (on-board chip antenna and external antenna via u.FL connector)
- Better power button: We’ve gotten feedback that the power button breaks too easily, so now we’ve replaced with a more solid alternative.
- Improved battery cable fastening: To avoid weakening of the cables over time they are now run through a cable relief.
- Improved sensors: To make the flight performance better we’ve switched out the IMU and pressure sensor. The new Crazyflie uses the drone specialized sensor combo BMI088 and BMP388 by Bosch Sensortech.
Flow deck v2: The Flow deck has been upgraded with the new ST VL53L1x which increases the range up to 4 meters
Z-ranger deck v2: The Z-ranger deck has been upgraded with the new ST VL53L1x which increases the range up to 4 meters
Multi-ranger deck: Finally the Multi-ranger deck is currently in production and will be available during the fall!
Mocap deck: The motion capture deck with support for easily attaching markers
“Roadrunner” (alpha): With TDoA3 to be included in the next firmware release we’re happy to release one of our LPS tags code named “Roadrunner”. The hardware is basically a Crazyflie 2.1 without motors and up to 12V input power.

In the upcoming weeks we’ll post more details about the products and when they will be available, so stay tuned!

We should also mention that we will showing off some awesome prototypes of products that are planned to be released next year, among them:

“RZR”: The long awaited Crazyflie + BigQuad stand-alone combo code-named “RZR” is making it’s way into production and we are aiming to release it during the beginning of 2019. Basically it’s a Crazyflie 2.1 where instead of motors you can directly connect ESCs to build bigger quads up to around 0.5kg.
Lighthouse deck: Our current prototype is now flying with both Lighthouse 1.0 and 2.0 and the performance is awesome! This is definitely the next product out the door after the list above and we’re aiming at having it available during the spring.
Raspberry Pi Zero power deck: This deck allows you to add a Raspberry Pi Zero to the Crazyflie 2.x and the “RZR”.
LPS tag: We’ve shown this tag before but now we’ve updated it to use the Crazyflie 2.1 IMU and to have proper mounting holes. We’re getting closer to release and this will hopefully be available during the spring.

During IROS this week we will be showing off all the products above (including the prototypes). So if you want to be one of the first to check them out drop by our booth nr 91.

Preparations for IROS 2018

2018-09-24 | Kristoffer Richardsson | Leave a comment

We are working hard in the Bitcraze team to prepare and get ready for IROS 2018 in Madrid next week. As usual preparing for fairs and exhibitions make us add useful features and functionality that we might not had planned to implement but that we find useful or need. Even though some of it might be a bit hackish, most of it will add value to the project and will hopefully be useful to the community. Notable functionality that we are working on this time:

design for a 3D-printable charging pad
basic support for the experimental Light House deck
support for the high level commander in the python lib
“app” for autonomous flying running in the Crazyflie

Charging pads

The plan is to fly a small crazyswarm with 6 Crazyflies using a motion capture system from Qualisys. Since we want to spend as much time as possible talking to people and minimize setup time, we were looking for a solution to automatically recharge the batteries between flights. We are planning to use Qi-charger decks for contact less charging with 3D-printed landing pads with slopes to make the Crazyflies slide into the correct charging position even if they land a few millimetres off.

The Light House deck

Even though the Light House deck hardware still is very much experimental we have started to add support for it in the Crazyflie firmware. Hopefully we will be able to run our demos using either LPS or the Lighthouse to show the difference in performance.

Support for the high level commander in the python lib

The high level commander was contributed by Wolfgang Hoenig and James Alan Preiss (thanks!) an has been available in the Crazyflie firmware for a while. In an environment with positioning support it provides high level commands such as “take off” and “go to” as well as flying user defined trajectories and is used by Crazyswarm. We wanted to use the same functionality in our demo but running it stand alone in the firmware. The easiest way to get acquainted with the functionality was to play with it from python and as a side effect we implemented the API in the python lib for anyone to use. There is also an example script called autonomous_sequence_high_level.py in the examples directory.

App for autonomous flight

For ICRA last year we wrote code in the Crazyflie firmware to fly trajectories autonomously. At that point we simply fed setpoints to the PID controller to make the Crazyflie follow a preprogrammed path. Now we have more tools in the Crazyflie toolbox (the high level commander and the Mellinger controller) and by using them we have reduced the amount of code needed and complexity of the solution while the performance has been improved (code on github).

Shipping with FedEx and updated Loco positioning node

2018-09-17 | Marcus | Leave a comment

E-store

Like we’ve mentioned a few times before it’s not always easy shipping batteries. Due to this we’ve unfortunately had to switch off checkouts containing batteries to some countries (like Canada, Australia and India). We’ve finally found a workaround for this, so today we’ve switched from using DHL to using FedEx in our E-store. As a positive side-effect of this most customers will also benefit from lower shipping rates on their orders. As always if there’s any issues with shipping or ordering please let us know and we’ll do our best to sort it out.

Loco node Rev.E

After receiving feedback from some customers that the micro-USB connector on the Loco nodes broke we’ve decided to update the design. So in the coming weeks we will start phasing in the new revision (Rev.E) of the Loco node and phasing out the old one (Rev.D). Aside from the updated micro-USB connector we’ve also connected more spare pins to the expansion connector on the board. For full details on the schematic changes have a look at the the Rev.E schematics over on the wiki. As a side-note it’s worth mentioning that the first batch of Rev.E Loco nodes have a dark blue silkscreen instead of the standard Bitcraze black silkscreen, this will be updated in future batches.

Demo for iROS2018: The lighthouse deck

2018-09-10 | Arnaud | 1 Comment

As mentioned in an earlier post, this year we are going to exhibit at iROS 2018 in Madrid. Every time we go to fairs and exhibition, it is the occasion for us to work more on integration to put together the latest development into a demo we can show at the event. One of the latest development we will show at iROS is the lighthouse deck.

Work on the lighthouse deck have continued during the summer and we are now at a stage where things are starting to work quite well with Lighthouse V1 base stations. We are quite impressed by the performance: we have measured a positioning noise bellow 1mm. We are flying the Crazyflie using Crazyswarm which allows us to fly smooth trajectory using the high-level controller:

The goal for iROS is to stabilize and push the code in the main Crazyflie firmware repos. We will have a couple of Crazyflie setup with the Lighthouse deck and that we will be able to demonstrate. In the future we are also thinking of making a general purpose tag that could be used with other robots. One of the great advantage of the lighthouse tracking technology is that the position and orientation is available in the receiver, in the robot. This means that, like the LPS, the robots are autonomous and do not require an active data connection with a computer in order to locate themselves.

There is still a lot of challenges and work to be done on the deck. For once, this is currently using HTC Vive lighthouse base station V1, Valve has release the base station V2 that allows to cover much more space for each base station and to use more than 2 base stations in the same system, we plan to implement support for it. We will also need to work on multi-sensor localization and setup procedure. Currently the Crazyflie calculates its orientation using only one lighthouse receiver and requires to be in direct light of sight of both lighthouse, it is possible using more receiver to get a position and orientation with only one base station in sight which will increase the system reliablility. As for the system setup we are still using SteamVR to obtain the lighthouse positions using at least one Vive controller, the goal is eventually to be able to setup a system with the Crazyflie alone, without needing to install SteamVR. All that will most likely be discussed in more details in future post.

If you are attending iROS 2018 feel free to come and meet us at booth #91.

Making TDoA 3 more accessible

2018-09-03 | Kristoffer Richardsson | Leave a comment

We started the work on TDoA 3 in May and it has been functional for a few months, but it is a bit cumbersome to make it work since it requires compiling firmware with special flags and running scripts to configure anchors. To rectify this and make it more accessible we are now working on integrating it just like the other positioning modes; TWR and TDoA2.

Changes

The anchors already contained most of the required functionality. We have added support to change to the TDoA3 mode via LPP, that is using the Crazyflie as a bridge between the client and the anchors, transmitting data to the anchors via UWB.

In the Crazyflie TDoA 3 has been added as a third mode. This means that it is now auto detected when the Crayzflie is switched on and it can be selected from a client – no need for compile flags any more! We have also added a new mapping to the memory sub system to transfer anchor information for a dynamic number of anchors to a client. This means that instead of being available to the client as a long list of log variables and parameters, most of the TDoA3 information and configurations are available in a memory map using the same protocol we use to access real memory like the configuration EEPROM or the deck memories. This way we have much more freedom to define and transfer the data-structure to and from the Crazyflie.

The python client/lib is the piece of software that requires most changes. The UI (and implementation) was designed to handle 8 anchors, but with TDoA3 it must support a dynamic and larger number. The new memory mapping has of course to be implemented in the lib as well. The anchor position configuration part of the LPS tab will be separated into a dialog box to get more space for the controls. We also have some ideas for improvements in anchor position configuration (saving to file and sanity checking of configurations for instance) that will be easier to implement in the future as well.

Feedback

The driver for this work is of course to make the TDoA 3 technology available to anyone that wants to try it out. It is important to remember that it still is experimental and that we have mainly tested it in single room setups with a few anchors. Our hope is that more users will use it in various settings and that we will get feedback and contributions to iron out any remaining problems. We currently lack easy access to larger spaces which makes it hard for us to verify the functionality in a system with many anchors.

The code in the firmware for the anchors and the Crazyflie is mostly ready while there still remains some work in the lib/client, hopefully it can be committed and pushed during the week (see issue bitcraze/crazyflie-clients-python#349). If you want to try it out when the client is fixed, remember to upgrade the anchor firmware (including git sub modules), the Crazyflie firmware (including git sub modules), the python lib and the python client. Since this is still work in progress APIs and protocols may change until the first official release.

Log and param protocol V2

2018-08-27 | Arnaud | Leave a comment

Log and param are the two Crazyflie subsystems that have become the core means of communication with the Crazyflie.

The Log is a subsystem that contains functionality to transfer values of variables in the Crazyflie to a client. The client can setup log blocks, which are a list of variables, and start logging this log block at a certain rate. The Crazyflie will then send radio packets at the requested rate with the current values of the variables, thus enabling the client to read changing variables in the Crazyflie in near realtime. It is very useful for monitoring the state of the Crazyflie and further more, any log variable can be graphed in the python client.

Param is a subsystem that contains functionality to get and set the values of variables in the Crazyflie. This is essentially the opposite of Log, it allows the client to read or write variables that are read-only in the firmware.

Both subsystems are based on a Table Of Content (the TOC): at connection time the client pulls the list of log/param variables. This means that there is no hard-dependency between client and firmware and that we can develop new functionalities in the Crazyflie, adding log and param variables to access it without modifying the client.

The Log and Param subsystems have served the Crazyflie community very well, allowing for quick development of experimental and new functionalities. There has been a limitation that has become more and more painful lately though; we were limited to 255 variables due to the protocol using only one byte to encode the variable ID. This issue has now been fixed in the Crazyflie firmware and in the Crazyflie ROS driver by a pull request from Wolfgang at USC. We have recently also implemented the required changes in the Python lib to make it available in the python client (and any other python script using the lib). In the process, some bugs unfortunately found their way into the code, but they have quickly been fixed by a pull request from simonjwright. Thanks to every one involved!

So now Crazyflie supports up to 65535 log and 65535 param variables. This time we should be good for the foreseeable future! ;-).

Raspberry Pi Zero power deck

2018-08-20 | Tobias | 7 Comments

Ever since the Raspberry-pi zero was released we wanted to find-out what it would take to fly one with the Crazyflie 2.0. One immediate issue is the size and weight of the R-Pi-Zero. It is just a bit to big and heavy to make it work without modifying the Crazyflie 2.0. Also it requires 5V power which is something the Crazyflie 2.0 doesn’t provide if USB isn’t connected. Actually the R-Pi-Zero works well down to ~3.6V but this is still too high to reliably run directly from a single LiPo cell. So to begin with we created a Raspberry Pi Zero power deck. It is reusing the same step-up/step-down (STBB1) as used on the LED-ring to make things simple and the output is set to 3.8V. Other than that the UART and the I2C interfaced has been connected so that the raspberry pi zero could control the Crazyflie.

The raspberry pi zero would then be soldered to the deck with 0.1″ header pins. The result can be seen below and the power part works well. We chose to solder the deck header pins to the deck, instead of using the female deck connectors, to make it more sturdy. Another thing we did was fitting a Pi-camera using a 3D printed mounting bracket we designed. We think this is one of the interesting use cases, to run computer vision or maybe neural networks :-).

Well unfortunately this only solves the first part, powering the R-Pi-Zero from the Crazyflie 2.0. Next step will be to modify the Crazyflie 2.0 with bigger motors/props so that is can carry it for a decent time. So story to be continued…

We’re back!

2018-08-13 | Kristoffer Richardsson | Leave a comment

The summer has been unusually long and warm here in Sweden, with a never ending sun beaming on the Bitcraze team members enjoying our vacation. As usual, at least one of us has been in the office at any given time, but staffing has been sparse. We apologise for delayed answers to emails and similar.

Even though we have been enjoying some time off, we have also managed to do some clean up of tasks that have been long over due. For instance merging pull requests and fixing a few nasty bugs (for details please see github), and implementing long overdue functionalities like being able to have more than 255 log and param variable (when the Crazyflie firmware develoment started many years ago, we though that 255 variables ought to be enough for anybody).

Everyone will be back in the office this week but we plan to continue the cleaning a few more weeks. We hope to be able to do some work on TDoA3, the Crazyradio, impementing Crazyswarm functionality in the python lib and more generally everything we normally do not have the time to do.

We have some exciting projects coming up this autumn: In October we are going to IROS where we will try demo a swarm in 2x2x2.5m, we also have quite some hardware that is now very close to be finalized that we should be able to release and start shipping before the winter.

Stay tuned for more products and blog posts!

Crazyflie RZR control board progress

2018-08-06 | Arnaud | Leave a comment

We have been thinking for a while about making a Crazyflie control board that could be used to make a bigger quadcopter using the Crazyflie firmware and deck. This idea has materialized in the Crazyflie RZR project.

The Crazyflie RZR is a quadcopter controller board based on the Crazyflie design, as pointed if our previous blog post, it is intending to bring the strength of the CF2 but in a little bit bigger package :-). It runs the Crazyflie firmware and feature the Crazyflie 2.0 deck port. It is capable of driving brush-less motor controller and has an uFL port for an external 2.4GHz antenna. It also contains the new quadcopter-optimized Bosch BMI088 IMU. We have made some progress lately on the Crazyflie RZR, we have just got the first initial sample from the manufacturer shown in the picture above.

We are not sure yet when the RZR will be in the shop, but the project is definitely going forward. We will keep posting information about the project as it develop.

Lighthouse prototype deck development

2018-07-30 | Arnaud | 4 Comments

We already wrote in a previous blog post that we where working on a Lighthouse positioning receiver deck for the Crazyflie 2.0. In this post we will describe a bit what has been the development process so far for this deck as it is an example of how to develop with the Crazyflie. Basically, our way of working often is to try to get one things working after another, this is what we have done here: we start from a hack and then we replace hardware and software pieces one after the other to make sure we always have one half (hardware of software) we can relie on.

The lighthouse deck started as a Fun Friday project, and as such we usually want to hack something together to see if the idea can work. So I looked around the web to get some information as of how to receive the lighthouse positioning signals and decode it. I found the vive-diy-position-sensor GitHub project by ashtuchkin. The project describe the schematic and contains the software for a Teensy board to receive a lighthouse 1.0 signal and calculate the position of the receiver. I went forward and cabled the circuit on a Crazyflie prototyping deck and attached a Teensy board to another prototyping deck. The idea is to install these two board above and bellow a Crazyflie:

Discreet-component Lighthouse receiver

Teensy to decode the lighthouse signals

The signal from the lighthouse receiver goes to the Teensy, then the serial port of the Teensy is connected to the serial port of the Crazyflie. As a first approach the Teensy was configured and we could get the position data using the Teensy USB port. When everything was working correctly I could implement a small deck driver in the Crazyflie to receive the position and push it in the Kalman filter. This way I could get a Crazyflie 2.0 flying in lighthouse with minimal firmware work.

The obvious next step was to get rid of the Teensy, this was done by implementing the lighthouse pulse acquisition and interpretation in the Crazyflie. Once that was done, we could make our own deck. Instead of using op-amp we used the official receiving chip available at this time, the TS3633:

First lighthouse receiving deck prototype

This board implements up to two receiver which would allow to get the orientation as well as the Position of Crazyflie. Due to questionable soldering only one receiver has ever worked but the prototype was useful to test the concept anyway, one of the lesson learned is that the receiving angle of the two flat is not big enough to fly very high, with the two lighthouse base station near the ceiling we could only fly up to ~1.5m before loosing the signal. We would need a microcontroller or other chip capable of acquiring the signals on the deck since the Crazyflie 2.0 deck port only has two input capable of acquiring the pulses.

At this point informations about Lighthouse 2.0, the next version of Lighthouse tracking that will allow to cover much bigger area, started appearing on the internet and a new receiver chip was release to receive the signal, the TS4231. One big difference was that Lighthouse 2.0 would transmit data in the laser carrier. The data transmitted are in the range of 1 to 10MHz dixit the TS4231 datasheet so it makes them impractical to acquire with a microcontroller. This gives us a perfect opportunity to play with the iCE40 FPGA and the icestorm open-source toolchain that has just been release.

The result is a deck containing enough receiver to cover a much bigger flying space and an iCE40UP5K FPGA to acquire the signals sent by the lighthouse. There is already two prototype of this design: one without SPI flash, so the Crazyflie would have to embed the FPGA configuration bitstream and program it at startup and the latest one has an SPI flash so the deck can start by itself:

First FPGA-Based lighthouse deck prototype

Partially populated second FPGA-Based lighthouse deck prototype, now with SPI flash

As a first approach the FPGA will acquire the Lighthouse 1 pulses and send the raw timing via a serial port to the Crazyflie. The Crazyflie can then decode and interpret the pulse. I am currently playing with the idea of maybe running a picorv32 Risc-V 32 bits CPU core in the deck, this will allow to acquire and interpret the pulses in the deck and send angles to the Crazyflie, this would greatly lighten the processing load on the Crazyflie 2.0. Eventually this FPGA should be able to acquire and decode the Lighthouse 2.0 signals.

This is very much work in progress and we will write more about the Lighthouse deck when we have further results.