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Lighthouse&UWB deck

Posted: Sun Jul 14, 2019 1:38 pm
by Yuchao
I am trying to use lighthouse and UWB deck at the same time.And I observed that UWB can measure the distance from the lps node almost perfectly.
But the coordinates of the lighthouse have a lot of fluctuations.
the Cfclient console ["LH: Synchronized!"] repeatedly.
the lighthouse deck above and the UWB deck under the drone :D
the lights on the UWB deck is not lit.

Re: Lighthouse&UWB deck

Posted: Tue Jul 16, 2019 1:29 pm
by kimberly

I admire your effort, but unfortantely the LPS deck and the lighthouse are not (yet) compatible. Please check this wiki page to check their compatibility: ... eck_-_deck

You could check on how to change the pins that the LPS deck is using, to prevent it from conflicting with the lighthouse deck.

Re: Lighthouse&UWB deck

Posted: Wed Jul 17, 2019 1:52 am
by Yuchao
Thank you for your reply! :D
I saw "will be supported in the future, SW update" on the wiki and I want to use lighthouse as a replacement for Mocap. I don't know when you will upgrade this feature.

Re: Lighthouse&UWB deck

Posted: Wed Jul 17, 2019 8:15 am
by kimberly
Indeed, it would need a software update in order to make it to work. As you can see in the wiki link I've send to you, the UART1 port is the one that is conflicting with the LPSdeck (bcUWB).

I've asked this to Arnaud, who made the lighthouse deck, and he said that currently we use i2c to access the lighthouse deck bootloader and uart for the lighthousedeck firmware. This can be changed in the firmware, if the i2c link would be used for the deck fpga firmware, but somebody would need to work on this. Currently we are mostly focused on getting Lighthouse version 2 working (with the HTC vive basestations v2), so that has more priority at the moment. So I'm not sure yet when this future adjustment will be made.

However, if you or somebody from your lab is able to already look into this and contribute a fix, this will go a lot quicker of course :). The i2c is already in the bootloader so somebody could port it to the firmware.

Re: Lighthouse&UWB deck

Posted: Sat Jul 20, 2019 1:20 am
by Yuchao
Thank you! :D
In fact, users like us who don't have a lot of hardware knowledge usually want to verify an algorithm by crazyflie, so hardware compatibility is especially important. I don't know if you will change this software in v2. We urgently want a replacement for Mocap.

Re: Lighthouse&UWB deck

Posted: Mon Jul 22, 2019 9:29 am
by kimberly
The compatibility issue with the LPSdeck and the Lighthouse deck is not related to the future work we are planning for V2 compatibility.

Usually users only use 1 positioning deck on their crazyflie, but I'm assuming you are doing this since you want to measure the accuracy of the positioning systems?

Re: Lighthouse&UWB deck

Posted: Sat Jul 27, 2019 7:26 am
by Yuchao
We want to use UWBdeck for local communication and behavior between drones, but we also need an additional positioning system to see how far it deviates from the true path.MoCap is usually used, but this is too expensive. :( :(

Re: Lighthouse&UWB deck

Posted: Tue Jul 30, 2019 12:18 pm
by kimberly
I understand.

So LPS system does positioning as well, so you could use that instead if you have the LPS nodes to your disposal. However, current modes (TWR,TDOA2 TDOA3) does not make it possible for communication between drones. However, if you would adjust the code itself, that it switches between positioning and intra-drone ranging/communication regularly, you might get something to work that you would not need the lighthouse for.

However, if you don't care that much about ranging but you do about communication, there is now a peer-to-peer functionality in the crazyflie2-nrf-firmware (checkout this commit: ... 34b1a2a636). Ranging is not great, unless you are fine with using signal strenght, but the crazyflies are able to communicate to eachother directly.

Sorry there is no immediate solution to get the LPS deck to work with the lighthouse. Arnaud is back in 2 weeks so I'll remind him to help you out with this.

Re: Lighthouse&UWB deck

Posted: Sat Sep 21, 2019 6:32 am
by shanfeng
Hi, we are going to take your advise to change the pins that the LPS deck is using, to prevent it from conflicting with the lighthouse deck.

We checked carefully the file loco_deck_revd.pdf which is attached partly, and found that we can switch IRQ/RST from RX1/TX1 to IO2/IO3 by modify the LPS deck hardware. Attached please find the plan we are go to modify, would you please check for us to make sure this is the correct way to cut lines and connect pins.

Re: Lighthouse&UWB deck

Posted: Tue Sep 24, 2019 6:51 am
by tobias
Yes that is how you should do it, and you can always switch back later if needed.