Forum Rule: Always post complete source code & details to reproduce any issue!
Tab Content
  • brtaylor's Avatar
    Yesterday, 02:06 AM
    Thanks Mike, For the MPU9250 library, did you try both SPI and I2C? I just tried it with I2C and I'm not getting communication with Wire (I2C1, pins 18/19) and Wire3 (pins 16/17) is undefined. EDIT: nevermind, pins...
    1815 replies | 46214 view(s)
  • brtaylor's Avatar
    Yesterday, 01:53 AM
    Eigen (https://github.com/bolderflight/Eigen) seems to work on Teensy4.
    1815 replies | 46214 view(s)
  • brtaylor's Avatar
    02-14-2019, 06:58 PM
    Super easy software fix - just needed to initialize the internal regulator during startup. I'll get a modified core library available shortly. EDIT: Modified core library available here:...
    48 replies | 10884 view(s)
  • brtaylor's Avatar
    02-14-2019, 05:20 PM
    I dug into this more this morning. If I apply regulated 3.3V power to VIN, the board works. This board was designed to rely on the internal regulator in the MK66 microcontroller; however, the Teensy 3.6 does not use...
    48 replies | 10884 view(s)
  • brtaylor's Avatar
    02-14-2019, 12:35 AM
    Not OP, but thanks for the code and link, I'm tackling a data logging project currently. FWIW, my test results for a SanDisk Extreme Plus card are: SdFatSdioEX write benchmark SdFatSdioEx uses extended multi-block...
    6 replies | 214 view(s)
  • brtaylor's Avatar
    02-08-2019, 04:57 AM
    brtaylor replied to a thread SPI Slave in Project Guidance
    Oh wow, TSPISlave looks exactly like what I want. Going to give that a try, cheers!
    10 replies | 153 view(s)
  • brtaylor's Avatar
    02-08-2019, 01:14 AM
    brtaylor started a thread SPI Slave in Project Guidance
    I'm trying to transfer data very quickly between 2 Teensy 3.6's. I'm trying to use SPI, since that should be the fastest method. I'm using the following config for my SPI master Teensy 3.6: * CS: 10 * MOSI: 11 *...
    10 replies | 153 view(s)
  • brtaylor's Avatar
    02-07-2019, 04:24 PM
    brtaylor replied to a thread uNav INS in General Discussion
    Yes, NED. I can recommend Dan Simon's book for EKF. There are a few papers that mention the EKF presented here at a high level, but none (to my knowledge) go into the specifics. It's a very straightforward filter,...
    674 replies | 117083 view(s)
  • brtaylor's Avatar
    02-07-2019, 06:35 AM
    brtaylor replied to a thread uNav INS in General Discussion
    Hi Bruce, sorry I've been down with an upper respiratory bug for the past few weeks. And now I'm playing catch up. I haven't had a chance to track down exactly what I was experimenting with. The MPU9250 library I...
    674 replies | 117083 view(s)
  • brtaylor's Avatar
    02-06-2019, 11:53 PM
    There are arduino cores for STM32, but it really depends on the exact version. For example, this supports a few of the STM32s: https://github.com/GrumpyOldPizza/arduino-STM32L4 Also:...
    10 replies | 213 view(s)
  • brtaylor's Avatar
    02-03-2019, 04:12 PM
    Not yet. I've had limited time to debug it and my current scope is pretty terrible. I may manufacture one soon with a slightly different crystal, see if that fixes the issues.
    48 replies | 10884 view(s)
  • brtaylor's Avatar
    02-01-2019, 10:51 PM
    brtaylor replied to a thread uNav AHRS in General Discussion
    Honestly, for heading and tilt in walking conditions the AHRS might not be appropriate - I'm not sure you would see enough dynamic motion in that context. I would consider implementing a tilt-compass, which is what...
    920 replies | 121407 view(s)
  • brtaylor's Avatar
    01-31-2019, 11:42 PM
    No, this is a pretty oft asked subject. I suggest searching the forums for similar questions regarding updating firmware over different protocols. The only supported method is via USB and any other approach will require...
    3 replies | 115 view(s)
  • brtaylor's Avatar
    01-21-2019, 08:48 PM
    One final suggestion - if you are going to be doing floating point math on the second Teensy, give the 3.6 a look. It has a hardware FPU and can give you very fast calculations if you remember to use the float version...
    5 replies | 155 view(s)
  • brtaylor's Avatar
    01-21-2019, 07:03 PM
    If wire lengths between the two Teensys are small, my preference would be I2C with the Teensy reading the ADC's set up as I2C Master. You could transfer up to 101 kBytes/s if you overclock your Teensy 3.2's to 120MHz:...
    5 replies | 155 view(s)
  • brtaylor's Avatar
    01-20-2019, 06:16 PM
    Read this thread, it discusses an ADC library for Teensy that enables synchronous sampling of both channels: https://forum.pjrc.com/threads/25532-ADC-library-update-now-with-support-for-Teensy-3-1?highlight=pevide+adc...
    5 replies | 155 view(s)
  • brtaylor's Avatar
    01-19-2019, 04:15 AM
    I'm working on debugging this hardware design. Two boards have been manufactured with the same symptoms: 1. The bootloader shows up correctly when plugged into USB 2. The teensy loader loads the program and reboots,...
    48 replies | 10884 view(s)
  • brtaylor's Avatar
    01-16-2019, 10:42 PM
    So, theoretically speaking, if we run Teensy 3.6 at 240 MHz, we can compute that a single tick would be 4.1667 ns. If we used the newest overclocking scheme, which can get us to 256 MHz, that drops to 3.9 ns per tick. ...
    19 replies | 622 view(s)
  • brtaylor's Avatar
    01-16-2019, 07:08 PM
    You should be able to get the timer working - IIRC, using the Teensy 3.6 clock and counting cycles will get you 4 ns precision at 240 MHz. I've thought about creating a nanos() library, similar in functionality to...
    19 replies | 622 view(s)
  • brtaylor's Avatar
    01-14-2019, 06:28 AM
    Roughly in the $40's or $50's.
    6 replies | 257 view(s)
  • brtaylor's Avatar
    01-14-2019, 06:28 AM
    I think the approach is to extend the pin numbering (https://forum.pjrc.com/threads/54114-Extended-Pin-Numbering), with a forked Teensy core, and then let the community add support for various ports and libraries from...
    6 replies | 257 view(s)
  • brtaylor's Avatar
    01-14-2019, 12:47 AM
    Neat project! Regarding the Teensy 3.6 "Pro", see this: https://forum.pjrc.com/threads/53225-Teensy-3-6-quot-Pro-quot-Feedback I've got some initial boards and am in the process of debugging. Not sure how long it...
    6 replies | 257 view(s)
  • brtaylor's Avatar
    01-13-2019, 03:06 PM
    brtaylor replied to a thread uNav INS in General Discussion
    Mike asked a similar question and the honest answer is I don't remember, but should be working with it again soonish and find out why: https://github.com/bolderflight/uNavINS/issues/3 I would guess that you should...
    674 replies | 117083 view(s)
  • brtaylor's Avatar
    01-10-2019, 08:05 PM
    That's why you need the size as a function parameter as well. Consider memcpy, which is: memcpy(void *dest, void *src, size_t size) In your case, JarkkoL recommended: void EBYTE::SendData(const void *data_,...
    6 replies | 216 view(s)
  • brtaylor's Avatar
    01-04-2019, 06:49 PM
    The magnetometer will not show up on an I2C scan unless you specifically set the MPU-9250 into bypass mode (register 55, bit 1). Edit: mis-read post, looks like you have it in bypass mode to pick it up at 400 kHz....
    1815 replies | 46214 view(s)
  • brtaylor's Avatar
    01-02-2019, 11:16 PM
    Often I use analogWrite rather than the servo library. Noticed that the servo library would issue commands round robin, which old receivers would also do, but means a lot more delay if you are using lots of servos....
    1815 replies | 46214 view(s)
  • brtaylor's Avatar
    01-02-2019, 08:15 PM
    To me, I think the focus should be on users getting expected behaviour rather than performance. I think this is doubly important with Arduino users, who may not be digging into compiler flags. There are use cases where...
    1815 replies | 46214 view(s)
  • brtaylor's Avatar
    01-02-2019, 07:35 PM
    As far as I'm aware, there is not a good suffix to add to specify a double, only 'f' to specify a float. So, it seems to me like constants that are not specified would need to be treated as doubles on Teensy 4.0 rather...
    1815 replies | 46214 view(s)
  • brtaylor's Avatar
    01-02-2019, 06:08 PM
    brtaylor replied to a thread uNav INS in General Discussion
    Long term, yes, I would like to incorporate air data into the INS estimate when available. I'm not sure what the effect would be on output accuracy, but, it would help arrest drift in cases where GPS is unavailable for...
    674 replies | 117083 view(s)
  • brtaylor's Avatar
    01-01-2019, 10:00 PM
    The servo shouldn't have feedback over the signal line - I use a 3.3V signal to drive servos and power them anywhere from 5V to over 7.2V (high voltage servos) just fine with a Teensy 3.6.
    1815 replies | 46214 view(s)
  • brtaylor's Avatar
    01-01-2019, 09:55 PM
    Awesome!! One small nit - it's Bolder Flight Systems rather than Boulder Flight Systems :)
    6 replies | 1724 view(s)
  • brtaylor's Avatar
    01-01-2019, 09:53 PM
    50 Hz is still the "standard" for servos.
    1815 replies | 46214 view(s)
  • brtaylor's Avatar
    12-30-2018, 05:36 PM
    The cool thing is that nanopb is protobuffers. So I'll use nanopb on Teensy 3.6, regular protobuf on a BeagleBone Black or a desktop (which can transpile to C++ code, Node.js, Rust, etc). It all works together. You can...
    5 replies | 223 view(s)
  • brtaylor's Avatar
    12-26-2018, 11:39 PM
    brtaylor replied to a thread uNav INS in General Discussion
    Mike is the KF the 15 state INS or the Euler AHRS?
    674 replies | 117083 view(s)
  • brtaylor's Avatar
    12-26-2018, 11:35 PM
    brtaylor replied to a thread uBlox Library in General Discussion
    Not yet, but it's on my long term "to do" list. My goal is to incorporate it by overloading the class declaration, like: * Serial: UBLOX ubx(Serial1, 115200); * I2C: UBLOX ubx(Wire, 0x48); The rest of the methods...
    75 replies | 12429 view(s)
  • brtaylor's Avatar
    12-24-2018, 10:40 PM
    Our timing is good and we haven't had issues missing frames. I'm moving baseline components to the FMU because: 1. If a research software component completely locks up the processor, we still have auto control laws to...
    22 replies | 1188 view(s)
  • brtaylor's Avatar
    12-24-2018, 10:04 PM
    Ha, Curt works at the UAS Lab. We're actually using JSBSim at the moment - in the past we've used an in house Simulink based simulation and we may move back to an in house sim at some point in the future. Yes, we use...
    22 replies | 1188 view(s)
  • brtaylor's Avatar
    12-24-2018, 04:08 PM
    Sounds a lot like protobufs, but presumably, lighter weight. Neat!
    5 replies | 223 view(s)
  • brtaylor's Avatar
    12-24-2018, 04:05 PM
    One of the things that I did with UMN is migrate some of the RAPTRS v2 changes into v1. So, what you see online at https://github.com/bolderflight/RAPTRS is actually v1 with a bunch of improvements. I need to find a...
    22 replies | 1188 view(s)
  • brtaylor's Avatar
    12-24-2018, 03:59 PM
    brtaylor replied to a thread uNav INS in General Discussion
    Maybe it would make sense if motion is low (i.e. below some threshold), switch to a tilt compass?
    674 replies | 117083 view(s)
  • brtaylor's Avatar
    12-23-2018, 04:47 PM
    Awesome! That's great to hear.
    41 replies | 2705 view(s)
  • brtaylor's Avatar
    12-23-2018, 04:25 PM
    How is your calibration? That could be causing it.
    41 replies | 2705 view(s)
  • brtaylor's Avatar
    12-23-2018, 04:23 PM
    Hi Mike, which axis?
    41 replies | 2705 view(s)
  • brtaylor's Avatar
    12-21-2018, 07:32 PM
    brtaylor replied to a thread uBlox Library in General Discussion
    Hey Don, Where are you getting your F9P's from? I'm waiting for eval boards from uBlox, but I saw that CSG Shop has some for sale: https://www.csgshop.com/product.php?id_product=263 Also, feel free to pull...
    75 replies | 12429 view(s)
  • brtaylor's Avatar
    12-21-2018, 04:07 AM
    Thanks for the feedback! Too bad that you're not getting good satellite performance, let me know if you would like a refund. Works great in my workshop and yard, which is definitely not clear sky, but GNSS receivers are...
    41 replies | 2705 view(s)
  • brtaylor's Avatar
    12-20-2018, 09:23 PM
    Not sure if you're interested, but I have a set of stacking boards for the Teensy 3.2 or LC. One of them happens to be an RS-485: https://bolderflight.com/products/teensy/ The Teensy is basically two 14 pin headers....
    3 replies | 183 view(s)
  • brtaylor's Avatar
    12-20-2018, 02:44 PM
    brtaylor replied to a thread uNav INS in General Discussion
    Hi Bruce, Sorry I haven't gotten to your email yet. I don't have a good recommendation for a uBlox 8 series receiver with external antenna. Most manufacturers include only a patch antenna and expect the receiver to...
    674 replies | 117083 view(s)
No More Results
About brtaylor

Basic Information

About brtaylor
Location:
Portland, OR

Statistics


Total Posts
Total Posts
466
Posts Per Day
0.44
Last Post
Teensy 4.0 First Beta Test Yesterday 02:06 AM
General Information
Last Activity
Today 03:54 AM
Join Date
03-21-2016