News

Holoseat: 2017 Sprint 1 Stand Up 1

Added by J. Simmons about 7 hours ago

J's report
  • Did
    • Posted Sprint 1 Announcement on Holoseat News Feed
    • Wrote (and published) 2017 plan blog post
    • DEV-10: Select BT HID module from CHIP's BT module or an external one / DEV-11: Select BT Host module from CHIP's BT module or an external one - spent available free time reading up on Bluetooth and bought Make: Bluetooth ebook
  • Will Do
    • Write Sprint 1 blog post
  • Blocked?
    • Still on business travel for the next week, so operating at reduced capacity
Bryan's Report
  • Did
    • DEV-03: Fix Bug #276 (Sensors are 5v logic feeding into 3.3v inputs on the controller) - ordered logic voltage adjustment boards from Sparkfun
    • BIZ-11: Define schedule for checking and applying updates to website - discussed in sprint planning meeting and will include update checks in stand ups; updates current except one plugin (purchased and need the license key to update it)
    • BIZ-12: Setup either RSS feed or notification related to wordpress vulernabilities so we know when to check for emergency updates - RSS feeds subbed
    • BIZ-13: Schedule backups so that they are running - found plugin to monitor and backup plugin, but have not installed yet
    • BIZ-14: Determine frequency of backup/restore tests to confirm backups can be used - no significant progress
  • Will do
    • BIZ-13: Schedule backups so that they are running
    • BIZ-14: Determine frequency of backup/restore tests to confirm backups can be used
    • BIZ-09: Submit books for tax accounting - go though books
    • BIZ-01: Identify what reports need to be generated - start looking at reporting requirements
  • Blocked?
    • BIZ-11: Define schedule for checking and applying updates to website - waiting on license key for last plugin
    • Possible upcoming blocks around business travel

Holoseat: 2017 Sprint 1 Plan

Added by J. Simmons 4 days ago

Sprint 1 planning is complete. The focus of the sprint is to address admin tasks related to the maintenance of Model B, LLC, conduct initial research about running a crowd source campaign, and continue the research and development required to lock in on the final hardware design for v0.4. The full details of the sprint are below.

Duration: 8 weeks
Stand Ups: Wednesday nights
Start: Feb 22, 2017
End: Apr 19, 2017

Backlog and Full Sprint Plan (see Backlog and Sprint 1 tabs)

Key Development PBIs
  • DEV-02: Determine if we should use a tone ring vs. existing single magnet design
  • DEV-03: Fix Bug #276 (Sensors are 5v logic feeding into 3.3v inputs on the controller)
  • DEV-06: Test Keyboard USB HID over USB-Gadget
  • DEV-10: Select BT HID module from CHIP's BT module or an external one
  • DEV-11: Select BT Host module from CHIP's BT module or an external one
  • DEV-15: Port the controller side RJ-45 wiring from the v0.3 controller to the v0.4 controller
  • DEV-17: Port physical switch wiring from v0.3 to v0.4
Pre-Sprint Commitments
  • J - content management
    • Post Sprint 1 Announcement on Holoseat News Feed
    • Write 2017 plan blog post
  • Bryan - website admin PBIs
    • BIZ-11: Define schedule for checking and applying updates to website.
    • BIZ-12: Setup either RSS feed or notification related to wordpress vulernabilities so we know when to check for emergency updates
    • BIZ-13: Schedule backups so that they are running
    • BIZ-14: Determine frequency of backup/restore tests to confirm backups can be used

Pedal Bus: Getting started

Added by J. Simmons over 2 years ago

Just created our project. Woot!

Ground Sphere CubeSat Ground Station: Update for LNA production

Added by Aaron Harper about 3 years ago

All parts are in to complete the first batch of production LNAs and we have completed the artwork for the solder mask (template). Tomorrow will be a warm enough day to etch the aluminum to create the template. Once it is verified both visually and with the production of a single unit, a small batch (about five units) will be made. This may happen as early as February 9th (Sunday).

The only part left for the Mk2 unit will be the 3D printed base. I expect this to be completed and delivered to Quelab by the 12th. I may have time this weekend to drive down to Quelab to pick up the base and deliver parts for them to build their own Ground Spheres, verifying the build instructions.

Ground Sphere CubeSat Ground Station: Testing update for Prototype 1

Added by J. Simmons about 3 years ago

This update is based on a couple of emails from Tim at Southern Stars. The short version of the update is that we have limited access for conducting from orbit testing, so Tim and Scott jumped at a chance this past week to run a from orbit test. Unfortunately, the results are inconclusive at best, and disappointing at worst. They were unable to receive signal from the CubeSat in question. Read on for full details.

The test in question involves attempting to receive signals from AeroCube 4C. This CubeSat only broadcasts on 915 MHz when it is over its mission control center, so we have to make special arrangements to conduct the from orbit tests. Specifically, we need to coordinate with its operators and Southern Stars team members must drive with the Ground Sphere to the LA area in order to be under its footprint.

This past Thursday (Jan 2), a test opportunity was arranged. The operators believe they picked up the CubeSat's signal (they saw what appeared to be the signal on a spectrum analyzer) but were not able to establish a radio lock. The following from Tim details our even less successful results.

We were less successful. We saw a number of "blips" right around the expected 914.7 MHz, but they were all very short. We saw nothing like a continuous signal that dopper-shifted as the satellite approached and receded. I suspect the blips were all local. We recorded about 10 GB worth of raw RF samples from the SDR, and we'll go over these in more detail tomorrow.

I should note: we used Scott's SDR, rather than the SDR that was sent to us. I didn't realize this until after the pass began. Scott's SDR does not have the same built-in preamp and has a smaller gain (a few dB difference? Scott can you put a number on it?) This was a mistake on our part.

We also noticed that the GS antenna did not seem to produce noticeably any different signal levels when the power supply to the preamp was plugged in, vs. when it was not plugged in. I don't know what that means. Something may or may not be broken. Or we're just not interpreting the SDR output correctly (?)

Discussions between Aaron and Scott over email confirm there was a hardware issue with Prototype 1. The preamp's power connection came loose during transport so it was not in use during the test.

It should also be noted that this attempt at a from orbit test, due to the challenges with securing test opportunities, came well out of the established testing order (see [[Testing]] wiki page for more details). Neither the lab tests nor the field tests have been run, and both need to be run to verify and validate the prototype. In all likelihood, even the lab tests would have turned up the problem with the pre-amp.

We will be circling the wagons here shortly to continue the testing. More news as it is available.

Ground Sphere CubeSat Ground Station: RTL-SDR Dongle in Linux

Added by Jeremy Wright about 3 years ago

I plugged the dongle into my laptop and ran lsusb. The following is the output.

Bus 003 Device 005: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T

The vendor and PID numbers match up with this entry on the rtl-sdr page:

0x0bda 0x2838 E4000 ezcap USB 2.0 DVB-T/DAB/FM dongle

Aaron mentioned that SDR# has the ability to adjust the dongle's internal preamp gain. It runs on both Windows and Linux (via Mono), so I decided to give that a try using the instructions here.

The installation of the udev rules doesn't seem to work properly in the instructions above, but you can follow these.

The kernel also automatically loads the dvb driver module for the dongle to make it available as a TV tuner. This causes rtl_test -t to complain that something is already using the dongle. You can blacklist the offending module in /etc/modprobe.d/blacklist.conf with the line:

blacklist dvb_usb_rtl28xxu

For a quick kill of the driver you can just do:

rmmod dvb_usb_rtl28xxu

SDRSharp should be able to access your dongle then.

What it looks like is that it's rtl-sdr, not SDR# that adjusts the gain of the internal preamp. From what I see in the repo SeeDeR uses rtl-sdr, so it should be possible to adjust the gain through the library without writing code to directly talk to the dongle. Tim and Scott may already know this. I'll start a thread on the forum to ask.

Ground Sphere CubeSat Ground Station: SkyCube Launch Delayed

Added by J. Simmons about 3 years ago

Just saw the news that the Orbital Cygnus launch SkyCube is manifested on has been postponed until January. This delay is to give the ISS crew time to make repairs to the cooling system.

Mach 30 wishes the ISS crew speedy and safe repairs. And we eagerly await the January launch of SkyCube.

Ground Sphere CubeSat Ground Station: Update from Tim

Added by J. Simmons about 3 years ago

First, an update on our own launch. ORB-1 is now pushed back to December 17th, at 10:08 PM EST. Deets here: http://guestops.hq.nasa.gov
Scott & myself are both planning to be there.

Second, an update on ORS-3. I've heard from several sources that more than half of the 28 CubeSats launched on ORS-3 have not been heard from in space. (This comes to me independently from NPS, Pumpkin, and Spaceflight, so I tend to believe it.) This is an unusually high failure rate, and it's led to speculation that something went wrong with the deployment in space. You know as much as I know, now.

Unfortunately, one of the failures was Horus, the NPS Colony-2 satellite that has the same radio as SkyCube. It hasn't been heard from since launch. NPS has had intermittent contact with NPS-SCAT, but the problem there seems to be software/firmware instability that reboots the satellite frequently, preventing any kind of robust connection. On thursday last week, Gio told me they haven't heard from it for a week, and anyhow SCAT apparently downlinks at 2.2 GHz (S-band), contrary to what I'd ben told previously, so it's useless as a 915 MHz target.


So, this puts us back to only one possible (and difficult to test with) on orbit bird operating at 915 MHz. The Ground Sphere team will need to look at how this affects [[Testing]]. More news as it is available.

Ground Sphere CubeSat Ground Station: Corrected Link Budget posted (1 comment)

Added by Aaron Harper about 3 years ago

With the updated data from our partners, I have re-run and refactored the link budget. We are still good to go.

Ground Sphere CubeSat Ground Station: Preliminary Link Budget Calculations (1 comment)

Added by Aaron Harper about 3 years ago

The rough link budget numbers I used for go/no-go calculations are now available in the DMSF section. The spreadsheet was originally done for GS001 which was designed to receive transmissions from ISS, so the adaptation was relatively easy. There is a PDF file and the original spreadsheet in ODS (Open Office) and XLS (Microsoft) formats. To use the interactive spreadsheet, simply place values (known or guessed) in the value cells.

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