SAMD11C Multi-use board

I finally got a chance to play with the SAMD11C chips FabAcademy has been recommending for a while. I also wanted to learn to use KiCAD a bit more so I made a multi-use board with the SAMD11C which can be used for UART, UPDI programmer, and as a FreeDAP board. You can find all of my files for this project, including the firmware at my FabAcademy gitlab page.

I will be making a modification of the board Quentin designed.

I designed the board in KiCAD by modifying another of Quentin’s boards, the SAMD11C dev kit with USB-A connector.

To fabricate a PCB, I’ll use the Roland SRM-20 mill as well as my shapeoko/X-carve using Fab Mods.

The steps in this project are:

  1. Download my board files, code, and hex from here.
  2. Mill the PCB with Roland or other CNC
  3. Populate (stuff) the board with components
  4. Flash firmware to the chip
  5. Use this new board as a programmer or USB/UART

Milling a board on the SRM-20 through Fab Mods:

I’ve posted a more detailed explanation of exporting from KiCAD to a milling machine in this previous post.  Be sure to check that out when you get to that part of the process.

Go to http://mods.cba.mit.edu/

Right click anywhere on the screen and select “program” then “open server program” and search for Roland→SRM-20 → PCB png. To use any other CNC (Shapeoko, Xcarve, 3018, etc.) you can select G-code→ mill 2D PCB png. This will accept in a PNG image file and generate the cut file you will send to your machine.

clip_image001

Then we’ll modify this to save a file for us.

clip_image002

 

If your X, Y, and Z, look like the GIF above, you’ll do an “air cut”.  An “air cut” is a test that runs the same code, just offset in the Z axis  (and this case X and Y as well) just to make sure everything will cut as you would expect. Then you’ll regenerate your cut file by changing the X, Y and Z defaults to 0s in mods before exporting your cutfile again.

 

Once the board is cut, it must be populated… Break out the old iron and solder up the design. If you don’t have a switch like the one I used, you can simply install some male headers and use a jumper to select the voltage. The SAMD doesn’t have a lot of external accessories which makes this part a good bit easier than say some of the older FabISP designs.

Once populated, the board needs to have firmware flashed to it. For this step, I will use the Atmel ICE programmer and a windows computer.

First download windows version of edbg which is the debugger tool we’ll use to download the firmware.

https://taradov.com/bin/edbg/

I downloaded it to my desktop.

Then download the binary of the firmware. I am using the SAMD11C arduino bootloader core firmware so I can use the chip with the Arduino IDE and libraries. (This bootloader seems to eat up a good bit of memory, even on these ARM devices).

Connect up the atmel ICE programmer to the SAMD board. I used figure 3-8 from the atmel ice manual to figure out the pinout because we are using the Serial-Wire debug (SWD) pinout.

Above you can see the specific pins for programming the firmware with the Atmel ICE. Pin 1 is Target Voltage (Vcc), pin 2 is SWDIO, pin 3 is GND, and pin 4 is SWDCLK. Pin 10 is the Reset.

Here are the pins and usage of the board:

Finally you’ll need to open the command prompt in windows, cd to the directory you downloaded these files to and run the following command (assuming you went with the 2nd firmware option above):

edbg-windows-r24.exe -bpv -e -t samd11 -f sam_ba_Generic_D11C14A_SAMD11C14A.bin

You should see:

Debugger: ATMEL Atmel-ICE CMSIS-DAP J42700050854 01.00.0021 (SJ)

Clock frequency: 16.0 MHz

Target: SAM D11C14A (Rev B)

Erasing... done.

Programming.... done.

Verification.... done.

The first time I did it I got this error:

Debugger: ATMEL Atmel-ICE CMSIS-DAP J42700050854 01.00.0021 (SJ)

Clock frequency: 16.0 MHz

Error: invalid response during transfer (count = 0/1, status = 0)

I unplugged everything, replugged it and tried again and it worked.

This firmware only allows arduino to program the chip via USB. Let’s now install the correct board info to arduino so we can do that.

In the arduino software, go to File→Preferences and click the icon next to “Additional Boards” and paste the following:

https://www.mattairtech.com/software/arduino/package_MattairTech_index.json

 

Then you need to install the SAMD boards. In Arduino go to Tools→Boards→Board manager

Search for “SAMD” and install the “MattairTech” one only.

Once this is installed (it will take a bit of time) We can write some arduino code to run on our new board. Let’s start with a blinky program. Looking at the pinout of the SAMD11C, we can choose a pin to connect an LED to on a breadboard.

(Image source: https://gitlab.fabcloud.org/pub/helloworld/index/-/tree/master/SAMDino.%20Hello%20SAMD11C14 )

 

You better make sure that you always use “INTERNAL_USB_CALIBRATED_OSCILLATOR” when you plan to keep this plugged into the USB port for power, or “INTERNAL_OSCILLATOR” when you want tit to be standalone. If you select the other two options, you’ll have to reprogram the firmware with the ICE or a DAP.  It basically bricks the chip if you tell it to use an external crystal but don’t add a xtal to your design.

Arduino file to be serial print to test. The pinout is simple. Each output uses the same pin number as the SAMD chip output. This is unlike a normal Arduino.

ATsamD11C14A Arduino pinout

   0 -------------------
  5 | A5                 A4 | 4
  8 | A8 (XIN)        A2 | 2
  9 | A9 (XOUT)   Vdd |
14 | A14             Gnd |
15 | A15             A25 | 25
28 | A28/RST     A24 | 24
30 | A30            A31 | 31
    -------------------

 

You can download this code to test your board (whether you have a working LED or not). Once this uploads, open the serial terminal and you should see “hello”

 

void setup() {
   SerialUSB.begin(0);
}

void loop() {
      SerialUSB.println("hello"); //Send stuff from USB to serial port
} //end loop

If you want to test to make sure that your board can now be programmed from the Arduino IDE, you can flash the built-in LED on pin 2 with this code:

int led = 2;

// the setup routine runs once when you press reset:
void setup() {
  // initialize the digital pin as an output.
  pinMode(led, OUTPUT);
}

void loop() {
  digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);               // wait for a second
  digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);               // wait for a second
}

The following Arduino file makes this board into a UPDI programmer when you add a jumper to the appropriate pins (see above). Simply take data from the USB serial port and put it on the output serial port and vice versa.

 

void setup() {
  
   SerialUSB.begin(0);
   Serial1.begin(57600, SERIAL_8E2); //Adjust baud rate and use SERIAL_8N1 for regular serial port usage
}

void loop() {
   if (SerialUSB.available()) {
      Serial1.write((char) SerialUSB.read()); //Send stuff from Serial port to USB
   }
   if (Serial1.available()) {
      SerialUSB.write((char) Serial1.read()); //Send stuff from USB to serial port
   }
} //end loop

 

Program a target board over UPDI:

Once you have downloaded the above serial code to your board, you can use it to program attiny412 or attiny1614 chips over UPDI.

  1. First, you want to get a Attiny board. Here’s a great simple board to try.
  2. Get the code from that link to blink the LED on pin 0.
  3. Most important part==>In arduino, change the chip to the attiny412!!! If you don’t do this, you’ll accidently reprogram the samd which you don’t want to do. If that happens, go back and put the serial UPDI code above back on the samd.
  4. Change the “programmer” to “SerialUPDI – SLOQ: 57600 baud, any platform…”
  5. Wire up the samd board as shown below. The white wire is the jumper described above to put the board into UPDI mode. The other wires connect to a target board.

 

To program other samd chips with this board:

If you want to use this to program other SAMD boards, you’ll need to download this Free-DAP firmware and flash it to this board using the edbg program as explained above. This now becomes a programmer for other boards (called target boards). Connect up the target board to this one correctly (follow pink pin names as shown in the explanation below) and then you can program the target SAMD board with some firmware using edbg as well.

Note that the pinout for the programmer for a target samd board.

 

FUTURE WORK:

I’d like to take a page from Adafruit’s book and make the Free-Dap project into an Arduino project. Though I I’m pretty sure you can’t flash a bootloader to a SAMD using avrdude (hence the use of edbg). Adafruit’s solution is to have you load the bootloader to an SD card connected to the target board, then the arduino project just dumps the data from the card into the target board’s FLASH. Instead, I think I’d rather take a note from how pyupdi.exe was added to the Arduino IDE and simply include edbg.exe with it instead.

I’d like to make this same board also program ISP chips like the attiny45 or bare Atmega328s, but it isn’t a priority. It should be possible to do this through the ArduinoISP file but…. meh.

 

 

How to export to a CNC from KiCAD and Fab Mods

So, while working on a new board design I decided to learn KiCAD a bit more. I’ve detailed the board design and files in an upcoming post so keep an eye out for that one. Here’s I’m just documenting the process to make a board by exporting the design from KicAD and generating cut files in Fab Mods.

I came across a LOT of different methods looking at other Fab Academy students. Some had weird scaling issues or other problems.  I’m showing how to use two different methods for producing and SVG file.  Export–>SVG and plot as an SVG.  I also show two ways of generating cut files, whether you are making Gcode for a generic CNC or you’re making an RML file for a Roland SRM-20.  Note, I’m using KiCAD 5.4 on Windows 10 here.

In the examples below I’m using Quintin’s SAMD11C board found here.

 

Method 1: Export SVG directly from KiCAD to Mods

 

Method 2: Export an SVG using the “plot” function then convert to PNG for Mods:

 

Caveats and other important details:

I have rebuilt my shapeoko V1 as a PCB mill and so the difference between this and an SRM -20 Roland PCB mill is just what program you select from mods when you are creating the cut file.

If you aren’t running the websocket for fab Mods, you’ll need to replace the “websocket” module of the Roland programs with a “file save” as shown below:

 

Once you’ve exported the file you can follow this procedure on a Roland or other CNC machine to mill the board.

 

Once you populate the board, you can program this particular one with an Atmel ICE. Here’s the connections for that:

Connect up the atmel ICE programmer to the SAMD board. I used figure 3-8 from the atmel ice manual to figure out the pinout because we are using the Serial-Wire debug (SWD) pinout.

Pin 1 is Target Voltage (Vcc), pin 2 is SWDIO, pin 3 is GND, and pin 4 is SWDCLK. Pin 10 (Reset) is the back corner you can’t see.

Basic setup for all Raspberrypi projects

This is a starting point that I do on every one of my raspberry pi projects. You can branch off from this point to any number of projects. I used to like a screen and keyboard/mouse interface, but this is how to set up a headless rpi that you only control over the network. it is much easier than it sounds.

Hardware:

  • Raaspberrypi startup kit with power cable and SD card.
  • Computer (I have windows 10 but there are guides out there for mac and linux as well)
  • Wireless network to connect to
  • Maybe a camera to format the SD card?

Software Tools required :

  • SD card formatter (I use a DLSR camera because sometimes even this tool won’t format the cards right)
  • Balena etcher to burn the raspberryPiOS to the SD card

Firstly, I downloaded and installed the latest raspberrypiOS Lite to an SD card. Once it was installed, I reinserted the SD card into my laptop and created a wpa_supplicant.conf file in the partition I was able to open in windows (one will be openable, the other won’t be). This file sets up your Wifi settings so you can control the pi remotely instead of trying to find the right HDMI or component cable an display and connecting a keyboard and mouse to it.  I can simply ssh into the Rpi and run the scripts I need. This may sound intimidating, but it isn’t too hard at all.

Open a text editor (NOT word or notepad, download something like Sublime3 or notepad++) and create a new file names wpa_supplicant.conf. Paste the following and make sure to enter your WIFI’s credentials and keep the quotation marks.

country=US
update_config=1
ctrl_interface=/var/run/wpa_supplicant

network={
scan_ssid=1
ssid="Put your networks SSID here"
psk="Put your networks password here"
}

That will get the pi on the network, next we need to be able to actually control the Rpi from another computer on the network. To do so, just create a blank file with no file extension named “ssh” in the same SD card partition as wpa_supplicant.conf.  That’s it. This empty file just tells the Rpi to turn on ssh, which allows you to connect and control it remotely.

Now you can insert SD card into Rpi and plug in power to boot up.

With my older Rpi3 I give it like 5 minutes depending on the OS. Then you can check to see if your Rpi is on the network.  Open the command window in windows (windows key, then type “cmd” then enter) and type

ping raspberrypi.local

You should see a response. If it times out, then give it a little more time to install the OS and try again. If you can’t ping it (communicate with it ) after 15 minutes after you booted t up (or 30min or longer sometimes for a pi Zero w) need to start from scratch because something went wrong in your wpa_supplicant file. Triple check that the file is not saved as “wpa-supplicant.conf” or “wpa_supplicant.conf.txt” For that last one you may need to “show file extensions” in window’s explorer.

I always used putty to ssh into linux machines from windows, but Windows 10 apparently has ssh built right in, so you can just click the windows icon and type “powershell” to open a command window, then enter

 ssh pi@raspberrypi.local

We’ll use powershell instead of the Cmd window to allow us to copy and paste stuff into the window easily.

The first time you do this, it’ll give you a warning that it “can’t verify the [raspberrypi], do you want to continue”  just type “yes” and hit enter. Then you will be asked for the password. Note that as you type, you will see no letters appear in the terminal. This is normal for password entry on linux machines. The default username is “pi” and default password is “raspberry”.  When you type it and hit enter you should see a green line that says “pi@raspberry” which means you are logged into the pi.

The first order of business is to change the default password. type the following:

passwd

Enter your new password and you’re set. Now you can go off doing whatever random things you want to use the Rpi for.

To copy and paste into the SSH window you may need copy as usual form a webpage then right-click into the powershell window (maybe do this twice if you hadn’t already selected the powershell window) and it’ll automatically paste it for you.

Static IP: Next I like to set up a static IP address for my Pi so I always know where it is. This also helps things like streaming a webcam for Octoprint since the address won’t change. Android phones won’t use the mDNS entry of “raspbeypi.local” so if you want to use your phone to control or view things on the pi you need to set a static ip. Do so by issuing the following command:

sudo nano /etc/dhcpcd.conf  #this opens nano command line text editor to the IP address file...

My pi is on wifi  so I’ll adjust the wlan0, but you can replace this with “eth0” if your pi is using ethernet.

interface wlan0
static ip_address=192.168.0.100/24    
static routers=192.168.0.254
static domain_name_servers=192.168.0.254 8.8.8.8

This way I know all my raspberrypi stuff is found at 192.168.0.100. I can just type that in for ssh, or into a browser if I’m running a server on it (like octoprint, hassio, mjpg streaming video, etc.

Remote Desktop: To make it easier to connect to the pi in the future and to remote into it and control it’s graphical desktop from any other computer (such as your desktop or laptop), you can set up your pi to allow VNC. First, in your ssh terminal, we need to enable VNC.

sudo raspi-config

Then use arrow keys to select “Interface Options”.  Select “VNC” and you’ll be prompted to enable VNC the server. Then you can exit Raspi-config. On your desktop/laptop/other computer you need to install a VNC viewer which will allow you to connect. Visit https://www.realvnc.com/en/connect/download/viewer/ and install it. You should then be able to connect via the IP address of the pi, login to it and have full access and control as if you controlling it with your keyboard, mouse and monitor.

 

Remote shutdown:

Next you need to know how to shutdown and restart your rpi safely. It is a computer after all and I can’t tell if  just unplugging power will corrupt the SD card, so a safe method of shutdown is required. I use a couple. There’s a script you can add to allow shutdown by connection one of the GPIO pins to ground. This is essentially what you do on a regular computer’s power button. You tell the computer you’d like it to shutdown so it will trigger the shutdown functions. Secondly, you might want the ability to shut down or restart via ssh.

sudo shutdown -h now

or

sudo poweroff

and a restart is

sudo reboot

I’ve added a plugin and scripts to my octoprint setup to do the GPIO and I can shutdown from the web interface.

 

Now if at any point you mess up and can no longer communicate with the pi (setting the wrong IP address, etc) simply format the SD card in windows or in a digital camera and try again.

I recommend once you get all your settings correct, you backup your Rpi OS periodically. There’s a script that you can use to copy a bootable filesystem to another (can even be smaller) SD card you plug into a USB card reader on the pi.

Building a Zen Meditation or Seiza Bench for better Posture at my Desk

I used to have a standing desk for years, but since we moved, I haven’t found a similar solution. My posture is suffering because of it. I discovered that by resting on my knees at my computer desk, and raising my computer screen a bit I can get back in to the correct posture. I realized I could build a seiza bench would be the best solution to add a bit of support and reduce stress on my knees.

I began with an exhaustive search online but ended up just making my own. The design I liked most was this travel seiza bench from Sakura Co.  While they list the dimensions on their site, I found that to be too short for my needs. I experimented, having my wife help measure how high my butt was from the ground when I was in the best position, but the best experimentation was when I went to build the bench in the garage. I sat on a bucket which happened to feel like a comfortable height. I have a variety of buckets in the garage so I tried them all out. I took measurements of the ones I liked most and went about freestyling the design.

I had an old 7 1/2” wide by 3/4” thick pine board from a previous project laying around the garage, so I began with that. I laid out the 2 heights I measured and drew a diagonal line to connect them. This will be the final angle of the bench. Then I went about measuring and calculating the tab lengths. Here’s what I ended up with.

image

In that pic, I had already made my first cut. Basically the back of the bench is 11 3/4” tall, the front is 10 1/4” tall. this is a pretty steep angle, but I feels acceptable so far as I’ve been using it, though I haven’t used it much yet and I may end up making a different angled bench.

The tab that sticks up at the top rises about 2 1/8” above where the bottom of the seat will be. It has to be high enough to go through the seat and accept the holding pin to mount the legs with a bit of material on top of the holding pin. That’s how I came up with that measurement.

I tweaked the design from the inspiration more by having my tabs move at a 90 degree angle from the slant, rather than follow the edge of the board as in the bench form Sakura Co. This makes is far easier to construct.

This entire project can be built using 1 pine board, electric drill with a 3/4” drill bit, and a jigsaw. I had other tools available so I used a circular saw to cut the board all the way across as you see in the above pic.

Next, I used the bandsaw to cut the excess material away from the tabs. You can see that I forgot to tune my bandsaw before cutting.  This board looks pretty janky.

image

At this point, I messed again when cutting out the hole for the pin to fit into. I thought it’d be smart to drill a couple of holes just big enough for my jigsaw blade to fit into. I should have used the largest drill bit that would fit the hole instead.  This made for a nasty cut where the pin is supposed to be tight.

The idea is to drill a hole or two to give your jigsaw blade enough room to cut the edges and the corners. It takes a few passes from different angles, but I got it done. Now I got my 30+ year old jigsaw out of someone’s garbage can… it’s missing a few screws, but gets the job done, even if it isn’t very clean.

image

image

The next board was easier to cut since I tuned up the bandsaw. It came out with much cleaner edges.

image

I made the same mistake of using too small a bit to drill the hole, however I did learn something.  When drilling the hole in the first leg using the spade bit, I just drilled all the way through.  This tore out the back and made a nasty edge.

image

This time, I drilled a into the piece from one side until just the tip of the spade bit poked through the back and I stopped. I flipped the piece over and placed the tip into the hole to line it up and then drilled the rest of the way through the wood. This left a much cleaner edge.

image image

I’ll spare you the carnage from the jigsaw. It was better than the first one, but not good overall.

I then moved on to the seat. I cut a 22” long piece from the board. I measured 2 inches from each end to begin marking where I wanted the legs to mount. Due to the slat, the legs will stick out a bit from the seat about 3/8”.  I decided to make the front of the legs flush with the seat and allow that excess to hang out the back. No one will notice that, and I won’t be annoyed by it while using it.   I drew an arrow on each of the 3 parts to determine which side was the front. Then I traced the outline of the tabs for each leg on the seat board. I want as tight a fit as possible with this so it doesn’t wobble when I sit on it. Since each leg’s tab is a bit different due to my excrement woodworking skills, tracing the actual shape of the tab will get me a closer fit.

image

This is when I wised up about the spade bits. I mounted a 3/4” spade bit into my drill press and used the trick of going not quite all the way through the board, flipping it and drilling from the other side for a cleaner hole. Somehow I still managed not to get it perfect.

image

I made the edges and corners straight with the jigsaw again on each side.

Then I used some scrap wood and cut the pins on the bandsaw. I didn’t get a pic of them alone, but I made them wedge shaped with 2 right angles and a slanted side. One side 3/4” tall and the other 2 1/4” tall. The bottom edge (the longest edge which is at right angles to the sides) is 3 1/4” long.  I made two of them.

To even out some of the nasty straight cuts, I went to my trust poor-man’s belt sander setup by clamping my handheld belt sander in my workmate project center and locked the trigger in the on position as I maneuvered the parts on the 150 grit sandpaper. Put  the puzzle together and you have a bench!

I use a pillow on the ground under my knees to add some comfort, and I may eventually get either a couple of gardening knee rests (one for my knees and the other for my bum) or an hammock pillow for the seat. Given the ridiculous costs of hammock pillows though, I might just make a thin seat rest pillow myself to tie around the seat.

Loom and Guitar or Ukulele Strap Weaving

image

I became fascinated recently while browsing pinterest by examples by different weaving techniques. I began researching one method in particular called card weaving or Tablet weaving. Evidence shows it was used as far back as about 3,000 years in Europe. The fascinating part is that it is one of the earliest methods of algorithmic programming.

To do tablet or card weaving, you need to have some cards with holes in the corners. Through these holes, you pass threads of different colors. With every pass of the horizontal thread, you’ll spin the cards either forward or backward depending on what your pattern is. These designs are typically used to create belts or edging material for garments. Jess said this method was similar to making friendship bracelets. I wanted to build a ukulele strap for the ukulele Jess and I built a couple of years ago.

The first thing to do is create some cards. I used some larger-than-normal playing cards I got at the dollar store. These aren’t the best quality paper but they are glossy and slide across one another easily. Cut them to be square and I even rounded the corners with a corner punch to make sure they don’t snag on the corner when I spin them. I then used a hole punch to pinch a hole in each corner. I started with regular playing cards, but quickly realized that the larger the card is, the easier it is to use.You can see the steps below and the beginning of the cutting of the larger cards.

image      image

The next step is to have a loom. There are many different designs of looms. Some people simply tie one end of the strings to the back of a chair, and the other end to their belt which is the simplest method, however it isn’t easy to use. If you are just starting, this might make a lot of sense, but I was not successful with getting quality results this way.

Another loom design essentially uses a wooden box (box loom or rigid heddle looms) of some type that keeps about 2 feet of the threat taught, allowing you to weave easily. Here’s a version you can make out of PVC. Here is yet another PCV design. When you weave longer pieces, you can roll the threads onto spools at each end of the loom keeping the portion you are working on tight.

The loom style I chose to build was called an Inkle Loom.(Here’s a PVC inkle loom).  This is a traditional loom design that allows you to wrap the threads fully around a zig-zag path and tie the ends together to make continuous loops. To build this, I used the left-over parts from our Ikea Snigler crib hack shown here. I had half of  the crib wall sitting in the garage so I made a couple of cuts and screwed them together with 3” long screws (drilled pilot holes first of course).

image

image

It isn’t the most sturdy design as the dowels are mostly friction fit. A few have staples that somewhat hold them in. I can use it for this project and a few more without having to add additional support.

The next part that is required is the shuttle which holes the thread which is passed back and forth during the weaving process. I cut a piece of scrap clear acrylic on my bandsaw to look like a kite string holder and sanded the edges so they had a smooth radius. This makes sure it won’t catch other threads while weaving.

image

Now for the design I wanted to weave. I came across this particular pattern on pinterest from user Silvia Dominguez who has many great designs available.

card weaving pattern The way to read this chart is to look first at the little design on the bottom. It is 4 blocks high by 26 columns long.

imageEach column refers to one card or tablet. This means we will need to use 26 card (or tablets) each with 4 holes and threads through those holes. Each hole on the card should be labeled A, B, C, and D respectively and the color of each hole is listed from the bottom up in the design. i.e.
D
C
B
A

The design refers to the colors of each of the threads that are threaded through the each hole of the card.  I used 2 color of size 10 crochet thread. I got a light green and a darker green color to represent the grey and black of the design. Pull the strands out to the length of the finished object plug an extra 12-18 inches or so. For example, starting at column 1, it will use 4 strands of the light green in my case so I cut long lengths of thread for that card. Looking at a more complicated column, you can see column 4 uses two light threads and two dark threads, etc.

The next step is to thread the cards or tablets. It is very important how threads enter the cards. This is listed below each column. Depending on how they should be threaded, it is referred to as either a Z or an S. If you imagine your card on edge, the threads should come from the top of the loom into the card (top to bottom in the image below) If a card is a S card, all 4 threads enter from the left and exit the card on the right side. Here is a close-up of the rightmost column. You can see how all 4 of the threads enter the card with this angle\” like the middle of the letter S. This page (use google translate to read it) shows in detail with better graphics how this works.  image

Z cards of course enter on the right side and output on the right with an angle like “ / ”. 

The Z or S will allow the weave to be tight and you can actually tell the difference when looking at the end result.  If you have some of the threads on one card S and some Z, then the cards won’t spin and you can’t weave so be careful when doing this. Also, make sure to keep the cards in order.

Next wrap each set of 4 threads on the loom, zig-zagging on the dowels until you can just tie the ends of the strings together to make a continuous loop. The cards should be in the clear area (not inside the zig-zags). The threads should be a little taught. Not so tight that the cards can’t spin and not too loose that there’s a lot of slack in the threads. I actually ended up using a fisherman’s knot (basically two slip knots tied together) which allowed me to adjust the tension of each set of 4 threads as needed throughout the weaving process.

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Once you put all the threads on, align the cards so that the A-D sides of the cards are facing you all facing you. Next wind some thread on the shuttle. I did about 4 times the length of the other threads. You only need one thread on the shuttle.

A little weaving nomenclature: The long threads on the cards are called the Warp and the thread on the shuttle is called the Weft.

imageImage Source: https://buddhajeans.com/encyclopedia/warp-weft-diagram/

The area of space that is lofted by the cards is called the Shed. To weave, you pass the shuttle through the shed, then spin the cards to zig-zag the warp over and under the weft. Once you’ve done this that horizontal line is called the Pick. To begin, literally just leave an extra 6 inches or so of thread off the shuttle and just pass the shuttle through the shed. Once you do this you need to turn the cards. That’s where the larger portion of our design comes into play.

card weaving pattern

Start at the bottom at row 1. Once you’ve passed the shuttle through the shed, you’ll spin the the cards either forward or back based on which pick you are working.  In the yellow section it will tell you which cards will move forward and which will move backwards. I chose this design for its simplicity.All the cards are moved in the same direction. More complicated designs get really crazy and hard to follow. In this case, pick 1 rotates all cards forward. Once you spin the cards, you need to beat the previous pick with the shuttle to make it tight, then pull the slack out of the weft thread before doing the next pick.

I came across this site which was this person’s first tablet weaving project as well using the same design. She linked to a dead link to where she first saw this design. I found the wayback machine’s cache of the site and it turns out they used the same colors I did! I found NorseGirl’s website which did this design and uses the same colors. so much for being original, haha.

Once I wove about 4 feet of material,  I cut off the excess leaving about 1 foot on the end where the cards were. Jess braided these into a cord (which seems to be a traditional method of finishing the end). One the other end, I sewed a hem so it wouldn’t fray on that end and then sewed it to a 1.25 inch strap slider. I only needed 1 and was able to get it at the local outdoors store for less than $1.