Author: Marcus

During the fall we did two blog-posts (12) about a new prototype named Obstacle Avoidance/SLAM deck, but since then it’s been a bit quiet about it. So we thought it was due for an update! First of all, after a lot of discussions, we decided to rename the deck to Multi-ranger. It better describes what the board does and matches the naming of the Z-ranger. We’ve sent out some samples to customers and so far the response has been great. So we’re pushing forward and preparing for production that’s estimated to begin in March. Below is a picture of the latest prototype.

The biggest change for the final prototype is adding a LDO regulator to power the sensors. We’ve seen that depending on the settings for the sensors they might consume a lot more than when we initially tested. Using the same settings as for the Z-ranger brings the consumption to 90 mA, which together with the Crazyflie 2.0 electronics, comes close to filling the power budget for the Crazyflie 2.0 VCC LDO regulator. Aside from that we’re making some minor changes to simplify production and testing.

We’ll keep you updated on the progress!

We’ve been seeing an increase in the demand for a “programmable drone”, where users can easily give simple commands though scripting and the Crazyflie 2.0 following them. In order for this to work well you need a closed-loop control, i.e you need a reference system to see how you’re moving. Previously this was only possible using external camera systems or bulky on-board cameras. But a while ago we released the Flow deck which solves this problem. Thanks to the mouse-like sensor the deck contains it enables the Crazyflie 2.0 to see how it’s moving along the floor. Suddenly it’s possible to give commands like “move 1 m forward” or “fly in a clock wise circle with the radius of 1 m”.

To make it easier for users to pick out the parts needed we’ve put together a discounted STEM drone bundle. It contains all the parts needed for scripting the flight. If you have a gamed-pad or a Bluetooth LE enabled phone you can of course fly it manually as well :-)

To quickly get up and running, we have written a getting started guide. There is also a great hackster project, Beginner’s Guide to Autonomous Quadcopters by community member Chathuranga Liyanage, containing more details.

A few weeks ago we wrote about a new prototype that we call “the obstacle avoidance deck”. Basically it’s a deck fitted with multiple VL53L0x ToF distance sensors that measures the distance front/back, right/left and up of the Crazyflie 2.0. Combined with the Flow deck this gives you an X/Y/Z robot that you can program fly around avoiding obstacles which doesn’t need any external positioning system.

After implementing firmware support for the deck (see #253 and #254) we’ve finally had a chance to do some initial testing, see the video below. In the current implementation we’re doing the measurements in the firmware but using the logging framework to get all the distances into a Python script which does the movement control. Since we have the Flow deck attached we can control the Crazyflie 2.0 in velocity mode, which means we can say things like “Go forward with 0.5 m/s until the forward sensor shows a distance lower than 50cm” or “Go forward 1 m/s for 1s and rotate to measure the distance to all objects”. Since there’s no real-time requirements we can move the complexity of the algorithm from the firmware into external scripting which makes it a lot easier to develop. Now we’re really eager to start setting up obstacle courses and time how fast we can move though them :-)

The results from the testing shows that our two main concerns aren’t an issue: The sensors doesn’t seem to interfere with each other and we can sample them all at high-enough frequency without occupying the bus too heavily (currently we’re doing 20Hz). The next step is figuring out the requirements (i.e how many VL53L0x sensors are needed, do we really need the back one?) and a mechanical solution for attaching the sensors in production. If there’s any feedback let us know now and we’ll try to get it into the design. Also, we really need a new name for the board. Any suggestions?

At any given time we have a bunch of deck ideas floating around. Some of them might not be doable (or very hard), but still fun to discuss. Other we just never get around to since we’re always pressed for time. The “obstacle avoidance” deck is one of the latter ones.

The idea with the “obstacle avoidance” deck (current working name in lack of imagination) is to mount one of the VL53L0x ToF distance sensors, the same we have on the Z-ranger and the Flow deck, in each direction. This would allow you to keep a distance to the ground, avoid the walls (or any other obstacles you might fly into) and also keep away from the ceiling. Basically you could do a “turtle bot” that just flies around randomly without crashing. Another fun idea we’ve been discussing is being able to SLAM the room you’re flying in. If you can keep track of how you are moving around (with the Flow deck, Loco positioning system or any other means) while you’re measuring the distance on all sides you could make a map of the room.

After discussing this on and off for a some time, mainly focusing on mechanical and production issues of the design, we decided to just try out the concept with a simple prototype. The prototype, named “OA”, has daughter boards with VL53L0x sensors mounted front/back, left/right as well as one sensor facing up. It’s designed to be mounted on the top of the Crazyflie 2.0 and combined with the Flow deck which will give relative movement and also the sixth direction, distance to the floor. One of the issues with the design is that all the VL53L0x sensors are on the same I2C bus with the same address. To work around this the sensor has a nifty feature where you can re-program the I2C address. For this to work you need to release the reset of the sensors one by one: release the first reset, reprogram the address and then release the reset of the next sensor. The reset for the VL53L0x is not cabled on the Flow deck, so this is the first to be re-programmed. Then the reset will be released one-by-one for the sensors on the OA deck. In order to control the reset pins on the deck there’s a 8bit I2C GPIO expander. The reason for the GPIO expander is to use as few GPIOs on the deck connector as possible to keep the compatibility with other decks high. For instance the deck will work fine with the Loco positioning deck.


The goal with the prototype is to try out the concept of the deck and to see if it’s feasible. A few of the things we need to sort out is:

  • Mechanical solution for side senors (front, back, left and right)
  • Interference between sensors
  • Update rate when we have 6 sensors on the same bus which we might have to run one-by-one to avoid interference

The current status is that we’ve verified the electronics and written the I2C GPIO expander drivers to test all the sensors. The next step is to work on a new VL53L0x driver to allow multiple sensors running at the same time, which will force some refactoring of the firmware.  Once we’ve made some more progress we’ll do another post and report the results. If you have any feedback on the design/concept or have any ideas of what the deck could be useful for, don’t hesitate to drop a comment below.

Ever since we released the Alpha round of the Loco positioning system we’ve been talking about designing a more generic tag that could be used together with other robotics platforms for local positioning. We did a quick design of a prototype that we tested, but with the workload involved in bringing the LPS out of Early Access, finishing the Z-ranger and lots of other stuff , it’s remained on the shelf. But recently we’ve been getting more and more requests for this kind of hardware, so we thought it might be time to dust off the prototype and try to release it. One of the blockers (except workload) has been that we’re not sure how the tag should look mechanically and how to interface it electrically for it to be as useful as possible for our community. This post is for detailing the current status of the hardware/firmware and to see if we can get some feedback on what our community would like the finished product to look like.

The hardware

To make use of the firmware that’s been developed so far for the Crazyflie and the Loco positioning we aimed at making something similar to what we already have but with another form factor and slightly different requirements. As you might know the Loco positioning node can be configured as a tag, but there’s two drawbacks that we wanted to fix. First of all the Loco positioning node might be a bit big to put on smaller robots. Secondly the Loco positioning node can only measure the distances to the anchors, it doesn’t have an IMU to get attitude of the board and doesn’t have the processing power to run the same algorithms we have on the Crazyflie 2.0.

So for our Loco positioning tag prototype we decided to fix these. The prototype has the same sensors as the Crazyflie 2.0: Gyro, accelerometer, magnetometer and pressure sensor. It also has the same MCU as the Crazyflie 2.0: STM32F405. In addition to this it has the DWM1000 module for the ultra wide-band radio (used for positioning). We’ve also added the interfaces we have on the Crazyflie 2.0: SWD debugging, micro-USB for communication and power as well as a button. Looking at the pictures below you might also notice that we’ve added the Crazyflie 2.0 deck connector. So does this mean you can connect it to the Crazyflie 2.0? No, well not this prototype at least. The reason for adding it was we wanted to be able to use the same expansion decks as for the Crazyflie 2.0. So it’s possible to add the breakout deck for breadboard prototyping or the LED-ring for visual feedback.

So what’s the status of the hardware? Even though it’s the first prototype it’s fully functional and will give you positioning and attitude. What’s left is defining the electrical interfaces and the form-factor of the board so it can easily be attached to what ever you might want to track. The images below shows a side-by-side comparison with the current Loco positioning deck.

Loco positioning tag (on the right) compared to Loco positioning deck (on the left) (FRONT)

Loco positioning tag (on the right) compared to Loco positioning deck (on the left) (BACK)

The firmware/software

Like I wrote above we wanted to reuse as much of the firmware and software as possible. So the firmware running on the prototype is just a scaled down version of the Crazyflie 2.0 firmware. As you might have noticed the prototype looks a lot like the Crazyflie 2.0, except that it’s not a quadcopter and doesn’t have the nRF51 radio. So by “scaled down” I mean we’ve removed the motor and radio drivers, that’s about it. So how do you communicate with it? Well you can use one of the protocol available on the deck connector: SPI, I2C or UART. But the currently implemented way is using USB. Since it’s basically a Crazyflie you can use our client and python libraries to set parameters and log data values from it.


The current prototype is basically a USB dongle where you get position and attitude. It could easily be connected via USB to a Raspberry Pi, Beaglebone or any other SoC based platform or a computer. You can also interface it from an Arduino using the peripherals on the deck connector. The firmware is working and using the python library (or any other of our community supported libraries) you can easily get the position and attitude of the board. But to be able to take the next step and make something our community could make the most of we would love some feedback on the prototype. What kind of electrical interfaces and form-factor would you like?

Most of the time we have a few prototypes lying around that we’re working more or less on. Sometimes some of these make it into a product if we feel that they might be useful or fun for the community, like for instance the SD-card. Now it’s time for another prototype to be moved to manufacturing, a deck with VL53L0x laser ToF distance sensor.

On the Crazyflie 2.0 (and Crazyflie 1.0 10-DOF) we have a pressure sensor mounted to help control the altitude of the platform. Since air pressure is moving around a lot and the measurement is noisy it’s been very hard to get a rock-solid altitude hold working (although it’s getting closer). Already back when ST released the VL6180X we were looking at it, but the range was too short (10cm max). So when ST released the VL53L0x which has longer range (200cm max) we though this might be a good deck for the Crazyflie 2.0.

So we have a working prototype and thanks to stephanbro and Marcus Grieff we also have the firmware to use it with the Kalman filter. We are currently working at making it work together with the pressure sensor with the current altitude-hold mode.

Currently we’re working on verifying the hardware to make sure the power supply is good enough for it, but then the next step is production. Hopefully it will be available in a couple of months :-) Below is a picture of the current prototype.


Up until now, we’ve made our products available to customers through Seeedstudio and a number of distributors around the world. This has been a great solution since we’ve been able to focus on development of products instead of shipping packages and maintaining our own e-shop. When customers contact us and want to buy, we’ve been directing them towards local distributors where they can buy in local currency and with faster delivery times. But the last year more and more customers wanted to buy products directly from us and this has been taking up more and more of our time. The main reason has been complex purchasing procedures or local distributors not carrying the hardware the customer wants. Also if a customer starts discussing with us about what to buy, they tend to want to buy directly from us instead. Since we haven’t had a good set-up for this, we’ve been shipping packets on a case-to-case basis from our office basement (yes, the same basement where we fly with the Loco positioning). This has been very time consuming.

So, in order to optimize the sales and shipping, we’ve decided to launch our own e-shop. Our idea is that it is a complement to other distributors and the Seeedstudio Bazaar. Buying from local distributors will result in lower shipping costs and faster delivery. So we’re not aiming at replacing this, instead our goals are:

  • Have one place where we offer a full assortment of our products
  • Take responsibility for the end-to-end experience (both the purchasing and product support)

In order to service the e-shop, we’ve set up warehousing in Hong Kong, close to Shenzhen were the Seeedstudio manufacture is located. Aside from servicing the e-shop, this solution will also be used for drop-shipping custom orders, so replacing our basement packaging system.

As with most things, the more you know about something, the more you understand how complex it is. When we first started thinking about setting up our own e-shop/warehouse solution, we thought that this would probably take about a week: we evaluate a couple of solutions, select one and then just start selling/shipping. Turns out that things are more complex and this has caused a few weeks delay for the Loco positioning products since they will only be available through our shop. Now we’re hoping everything is on track, but we’re very new at this so please bare with us if there’s any hickups along the way when starting this up.

We’re opening up the store today, so you can have a look. Any feedback and comments are welcome! But as you might quickly notice, all the products are out of stock. The Loco positioning hardware as well as the other products are on their way to the warehouse, but they got a bit delayed along the way. Our best estimate is that the products are stocked at the end of the week or beginning of next week. The link to the e-shop is


Here’s a photo of some of the boxes. Looks a lot like normal boxes, but these contain the Loco positioning hardware :-)


After a hectic week we’re finally ready to put some new decks into production! A couple of months ago we selected 4 deck prototypes to try to bring to production before Christmas: WiFi, GPS, BigQuad and the Buzzer. After working hard on them during the last months, we’re now ready to release the Buzzer and BigQuad decks. Last week we ordered the first batches and the product pages and descriptions are being written this week. We’ll push out more information about the boards as it gets available, so stay tuned!

Below is a few quick shots of the latest prototypes:

So what happened to the GPS and the WiFi decks? The latest prototypes are working, but there’s still some minor issues. So instead of moving to production with the current design, we’re doing one last prototype iteration and launching the boards early next year.

On a related note we’ve been working hard together with Seeedstudio to get some more Crazyflie 2.0s into stock before Christmas. Not so surprisingly we’re not the only ones rushing to produce. But thanks to lots of efforts from Seeedstudios side the Crazyflie 2.0 will be back in stock in a couple of days!

cf2 front rosetteIt’s that time of year again, time for Christmas shopping. This year we thought that we would plan ahead and produce more units before Christmas to meet the demand. It was a great plan, but there were some hick-ups on the way. Originally the plan was that a fresh batch of Crazyflie 2.0’s would be rolling out of production right around now and being available in the Seeedstudio bazaar. But unfortunately we’ve only managed to get a small part of the batch out. And since demand is high before Christmas they were all sold out immediately. But we’re working hard to get the remaining part of the batch ready. The new time-plan is for the units to be finished around Christmas, which means they might not have time to ship to customers and be ready to get unwrapped by happy geeks around the world. But there’s still a chance to get a great present for your fellow geek (or maybe your own inner geek), check out our list of local distributors.

On another note we’re having some issues with shipment of spare batteries from China. New shipping and customs regulations have made it very expensive to ship spare batteries that are not included in products. Normally several orders of products are bundled together when doing the shipping/customs from Seeedstudio, but each battery now has to be handled separately with it’s own declaration and paperwork .We’re trying to find a way around this issue, but until then the spare battery at Seeedstudio will be listed as out of stock. If anyone has any tips on how to solve the issue, please let us know.

Last week and this week is busy with preparations for the New York and Berlin maker faires. Since we will be in the Seeedstudio booth we don’t have the same space as at the Bay Area Maker Faire, so we had to rebuild our “fly-cage”. The new specs are 1.7 x 0.7 x 0.7 meters. This is the area the Crazyflie 2.0 should be able to fly in for a full charge without touching the sides on the net.

We don’t have any special plans during the faire, except for flying during the day. So if you feel like meeting up, having a beer and getting lost in various technology discussions then leave a comment or drop us a mail.

The autonomous flying rig we used in bay-area was using the Kinect 2 sensor. This new rig is only using a standard webcam which is cheaper and easier to manage (ie. we do not need a Windows computer anymore). We are attaching an augmented reality marker on the top of Crazyflie and the image processing is mostly done by the ArUco library. ArUco is detecting the position of the Marker in 3D and the position is sent via zeromq to the controller. We used the same controller code as for the Kinect, we just had to tune it a bit better to keep in the smaller space. Then the controller is sending pitch/roll/yaw to the Crazyflie client setup to have a ZMQ as input device.


If you want to build the same cage then here’s a list of the parts:

  • Some kind of net (we used normal fishing net)
  • Fishing line (to tighten the cage)
  • Aluminium beam (for tents)
  • These 3D printed parts
  • Webcam with standard camera attachment (we use Logitech C920)
  • Camera attachment screw

We are in the process of cleaning up the code for the webcam. It will be pushed on Github and we will document the build on the Wiki.