Thursday, September 22, 2016

Vonets VOPWRT and How I Spent $8

Forgive the brevity. I don't want to waste much more time on this subject
  • I have WiFi.
  • I have a device that is old and doesn't support WiFi
  • I have experience mucking around in OpenWRT and have setup a few devices.

I figured I'd take this bullet list and put it to good use.
I went on eBay and found an $8 piece of hardware that uses OpenWRT. The Vonets VOPWRT. You won't find much information on Google about it. That should have been a red flag.

The first step of this project was to get this VOPWRT box on my WiFi. Start it up. Connect to the config as listed on the bottom of the box and try.

Try it again. Reset the firmware to factory. Try again the next day. Try again a different way. Try again a third way. Try a couple more different ways and fail. Try via command line stuff. Try again. Give up.

Decide to try upgrading the firmware. Checking the OpenWRT wiki where it lists the device. No supported version of it, but what ever. The version with mt7620a_mt7530 in the name sounds promising as it aligns with the specs listed. Download that and attempt to upgrade.

Flash the image to the device. Notice the upgrade seems to go fine. Watch as the device reboots and it is bricked. Open up the box. Notice no screws so you know it is a high quality product. Note the 3 empty antenna structures clearly designed to make you think it pumps out a great signal.

Take out the 8GB MicroSD card.
Throw everything else away.
Vow to not waste your money on more piece of garbage electronics

Saturday, February 6, 2016

Lubuntu Rythmbox Fix for AutoAudioSink and GStreamer

sudo apt-get install gstreamer1.0-alsa

FWIW, this is what happened to me installing Lubuntu 14.04 from a USB stick.

Did you install Rythmbox in Lubuntu and find that you can't use it because you get an error that says "Couldn't start playback" - "Failed to create autoaudiosink element; check your GStreamer installation" instead?

I did, and it was annoying. Couldn't find any real help anywhere no matter how much I searched. Eventually I stumbled across a bug report for it when I used the correct combination of magical keywords (not the autoaudiosink/gstreamer error). Hopefully you find this post faster now and it solves your problems.

The short version of the bug report is that Rythmbox isn't installed by default so they shouldn't support it by default and it acts differently than the audio players they do support, so ¯\_(ツ)_/¯ for now.

Rythmbox is trying to find an interface to output the audio. It knows that GStreamer has been installed and it tries to use it. Lubuntu's installation of GStreamer and fails trying to grab an autoaudiosink, whatever that is.

So you just need to give GStreamer a little something else to play with. Install the ALSA driver (make sure you restart Rythmbox) and go about your buisness.
sudo apt-get install gstreamer1.0-alsa

Thursday, February 4, 2016

The Art of Getting a Deal on a Sleep Number Bed

I've been through the process of buying a Sleep Number bed and in hindsight, this is how you should do it. If I followed these instructions I'd have been better off.

I don't and haven't worked for Sleep Number but the business model is pretty transparent.

Give Yourself a 3-4 Month Window To Buy a Bed

The Sleep Number people want you to buy a bed now. They'll tell you the best sale is right now but the truth is that all their sales are pretty similar. It's your job to take a look at them from a wider view.

Visit a Store with a Reliable Alibi

Get into whatever mall has the Sleep Number store and let the sales person give you the whole 9-yards and let you lay in all the beds. Come into the store knowing you are NOT going to buy a bed. You'll get less of a hard sale from the store if you tell them why you can't buy a bed (you could be closing on a house or moving to a bigger apartment in 2 months and don't have room to store it). Figure out which range of mattresses you prefer. Thank the salesperson for their time as you leave empty handed.

Visit the Website

There is no good reason to buy your bed at the mall store. The prices and discounts are the same and you won't get the hard sell on a new pillow or accessory. Now that you know which mattresses you liked start looking at prices. Ignore the discounted price for now, and assume you'll buy it at full price (but you won't). Still feel good about your possible new bed? Excellent.

Get Historical Discount Data

Remember how I told you to ignore the discounts? That's because they are useless without historical perspective. Does Sleep Number want you to get their historical discount data? They want you to think there is no discount like the discount today. Fortunately, they have a Twitter account dedicated to promoting current deals that you can use to harvest historical data. Did you notice that they tend to have a different mattress on sale each month? Add your favorite mattresses to the cart with and without bases to see how the current discounts size up. Odds are if there is no discount or a weak discount next Month will be better.

Realize the Base is a Scam

You may have noticed that there is some fluctuations in the the discounts, and that's to be expected in day-to-day marketing. But the bigger changes come because sometimes the discounts are on a "bed" and not a mattress. That means you might only get that $600 discount after you purchase the $300 base. Unfortunately, using only the Twitter data doesn't give you these numbers, but looking at larger trends you can make some estimated guesses.

Did I mention the Base is a scam? for $300 you get a big hunk of plastic. For $150 more you can get some legs on it. For less than that $450 you can go to Ikea or Wayfair and get a nice looking platform bed with a headboard and everything.

Check the Discounts Every Month

If you want to sign up for the mailing list or follow the specified Twitter account you can, but you may as well just check in on the website once a month. Every time they announce a new sale add it to your list of historical data. You'll get a good feel for when it's the right time to buy.

Tuesday, March 10, 2015

E3D v6 Hotend on a Printrbot Simple Metal (Introduction)

Welcome True Believers

Congratulations, you typed some worthwhile keywords into a search engine or had somebody recommend this great link. I'm going to assume you've got a working Printrbot Simple Metal and you are looking to upgrade your hotend and you smartly decided to pick the mostly highly regarded hotend on the market, the E3D v6.


I decided to start this journey because I noticed my thermistor seems to change it's mind over time (20 degree difference depending on the day). Did you know the standard Ubis hotend has the thermistor held in place with teflon tape? That's not even real tape, there's nothing to keep it from moving around.
Ubis Hotend Dismantled
You can see in the photo there is a little notch for the thermistor to sit in. It works well enough, but I want something more predicable with true user serviceable parts. I'm keeping my Ubis around because it still works, it's just not great.

Pain Points

The E3D v6 is a great replacement for the Ubis with 3 pain points.
  1.  The hotend is too efficient. It's shorter than the Printrbot was designed for. You'll need an adapter.
  2. The Ubis hotend has some Molex connectors that don't match the raw ends of the E3D v6.
  3. The hotend, like all good modern hotends needs a fan to be running at all times.
  4. The firmware on your board will need to be updated.
The adapter is easy enough to print out as long as you have a working printer. The hotend fan can be hardwired to the main power of your Printrbot and the firmware customization has been documented a thousand times. Don't be afraid. I'm here for you.


  1. Printrbot Simple Metal (with USB cable)
  2. E3D v6 1.75mm Universal (I bought mine from
  3. A printed hotend adapter (see Step 1)
  4. A bunch of little bits and bobs for a Molex connection
  5. Needle-nose pliers.
  6. Soldering iron and solder.
  7. A computer (I used OS X, but you can work it out)
  8. (Optional) Scrap of wire and bits of aluminum foil


  1. Print your adapter
  2. Assembling your hotend
  3. Wire your hotend
  4. Test your hotend
  5. Wire your fan
  6. Replace original hotend
  7. Firmware
  8. Autotune 
  9. Final hotend assembly
  10. Adjust your auto leveler
  11. Tweak your slicer
  12. Apply the sticker 

Sunday, March 8, 2015

Apply Your E3D Sticker

Part of a series on installing the hotend.

Display Your Pride

Remember when you were so proud to put that AMD sticker on your PC case? This is the modern equivalent. People who care about such things will want to know more about your hotend. Anybody else won't care and won't notice. There is lots of good real estate on your Printrbot so find a place for your sticker to live.

[placeholder for a photo]

Live Long and Print Often

You are done. Print all the things.

Adjusting Your Slicer

Part of a series on installing the hotend.

Compensate for Improvements

I don't want to say my Ubis hotend was bad but I usually had to have the hotend set at 200˚ or I would get pretty consistent clogs and failures. When I first got the Printrbot I was able to print around 190˚ and when it got cranky I'd had to print at 220˚. I usually had to set my flow to around 85% on the Ubis to get good measurements at 200˚ but that needs adjustment as well. With your new hotend you'll want to dial in your settings again. Find the perfect settings.

For me I was able to transition down to 185˚ for most prints with a little tweaking for the first layer to get optimal bed adhesion. I'm still working things out, but the temperatures I want for optimal printing will be a little easier to hone in on.

You can also speed up your print quite a bit. Of course the final speed you'll want to use will depend on how complicated your print is and how your filament reacts at certain temperatures, but I moved my minimum print speed to 60mm/s without issue.

Compensate for Cool Zone

You need to make sure that the hot filament doesn't retract into the cool zone on the new hotend. It'll lead to clogging and general bad feelings. The official documentation said that the furthest you'd could use 0.5mm-1.0mm for retraction, but I found occasional failures using 1mm. I'm sticking with 0.5mm for now.

Test, Test, Test

As with everything you've encountered on your 3D printer you'll want to experiment for a while to find the prefect settings for your filament, weather, altitude, etc.

Your Printer is Almost Perfect

 Just one last thing before you are done.

Saturday, March 7, 2015

Adjusting Your Auto-Leveling Probe

Part of a series on installing the hotend.

Introduction to Auto-Leveling

If you haven't watched Brook's video on setting up your Auto-lever, you should got and do that now.

Like the original setup you want your sensor about 3mm off your print bed when your hotend tip is touching the bed. You should go head and find something about 3mm tall, and remount your sensor then follow the video and get things setup properly.
  • M212 for writing a setting
  • M500 for saving your settings
  • M501 for viewing your settings

Don't Make My Mistakes

I thought I didn't need to readjust my sensor. It wasn't hitting the bed. It ended up that my sensor was only about 1mm off the bed and that wasn't good. Occasionally we all get threads and blobs from our prints that are too tall and a too low sensor will hit it and cause problems.

Always double check your Z index before attempting to print. M501 will display the current settings. Make sure you are awake, alert, and aware or you'll mistake Z -0.30 as Z -3.00 and you'll get a couple nice scars in your print bed. I'd include a photo of my print bed here, but it is too embarrassing.

Test, Test, Test

While you are printing your test cube don't be afraid to keep trying. Once you think you've got the settings perfect print 2 more times at the same setting to make sure it wasn't just luck.

Auto Leveled-Up

You should be an expert at setting that Z index. Now move on to adjusting your slicer.