Introduction: DIY Replacement Zeo Sleep Monitor Headband Sensor

By MarcioT's Home Page
About: I am a hobbyist with an interest in open-source software, 3D printing, science and electronics. Please visit my store or Patreon page to help support my work!

Last year I purchased a Zeo Mobile Sleep Manager. This is a nifty Bluetooth headband that tracks your brainwaves while you sleep and presents it on your smartphone as a graph indicating when you were awake, in light, deep or REM sleep. It's like having your own personal EEG. You can use your Zeo to improve your sleep, test the effectiveness of sleep aids, or to experiment with dream recall or lucid dreaming. As a data junkie, this was something I absolutely had to have!

Unfortunately, the Zeo uses a silver-coated fabric headband sensor that the company says needs to be replaced every few months to ensure optimal performance. These replacement sensor pads are expensive (about $50 for a three pack). Worse, it seems like the company that made the Zeo went out of business last March, so replacement sensor pads are not available at all now!

You can buy a Zeo on eBay, but in order to keep it running indefinitely, you will need to be able to make your own replacement sensor pads. The design of the sensor pad seemed fairly straightforward. After a bit of research and experimentation, I succeeded in making my own replacement headband sensors, and I'll show you how to make DOZENS of replacement sensors pads that will keep your Zeo going strong forever!

DISCLAIMER: Although I have tested these sensors on my own Zeo device, you assume all risks for damage to your Zeo device by making and using these replacement sensors. I am NOT affiliated with Zeo Inc. in any way and did not consult with them in making this sensor.

I make no guarantees about the performance of these handmade sensors vs the Zeo OEM sensors, but until Zeo Inc begins selling them again, I hope this guide will help people who already have a Zeo device and wish to continue using it.

Step 1: Materials and Tools

This project is relatively inexpensive when compared to buying replacement sensors from Zeo (although now that they are out of business, this is moot). For a little over $35, you can  buy enough material to make DOZENS of replacement Zeo sensors.

The most unusual material in this project is the conductive fabric for the pads that contact your forehead. I bought the MedTex 180 fabric from SparkFun and it looks and feels exactly like the material used for my original Zeo pads. The 12" x 13" sheet will set you back twenty bucks, but there is enough material to make about 30 sensor pads. For comparison, I also purchased the cheaper RipStop fabric from SparkFun ($9), but it seemed too stiff to work well. It might work, but I recommend spending the extra money for the MedTex 180.

The second critical component is the fabric snaps. They have to be the right size and style to snap into the back of the Zeo. I used Sew-Ology No 16 Pearl Snap Fasteners, 7/16 in and they worked perfectly. These are sold as packages containing matching studs and sockets, but only the studs will be used in this project. Each sensor pad will require three fasteners.

Hint: It is important that the studs and prongs be metallic and unpainted, as they need to conduct electrical signals. The first set of snaps I bought had bare metal studs but painted prongs. These can be made to work, but require more effort (I'll explain this later).

The rest of the materials in this project can be found at your local hobby and crafts store.

You will definitely need scissors and a hammer. If you use iron on patches as I suggest here, you will need a regular clothes iron. The iron on patches gives your project a nice finish, but are not required. You could also get away with just using plain fabric and sewing or using staples to hold it all together.

Having a 1/8 inch hole punch is helpful, but not required. Such hole punches can be found at your crafts store, but it might be tricky finding that exact size. You don't really need it, but it might help if you can find it.

Materials:
  - MedTex 180 Fabric ($19.95 for a 12" x 13" fabric sheet from SparkFun)
  - Heavy fabric (I used black twill, $1.75 for a large piece)
  - No 16 Snap Fasteners, 7/16 in ($4.29 from HobbyLobby)
  - Iron-on fabric patches (I got a set of several at the supermarket for under $2.00)
  - Yarn or string (I paid $5.99 at HobbyLobby for more yarn than I can use in a lifetime!)
  - Heat shrink tube or plastic stir straw
  - Double sided foam tape

Tools:
  - Scissors
  - Hammer
  - Clothes iron
  - Stapler (regular size and TOT50 mini-staples are helpful)
  - 1/8 in hole punch, such as this (optional, but very helpful)
  - Needle and needle threader (optional, but helpful)

Step 2: Print the Template

I have provided a PDF template for the Zeo Mobile device (Model ZEO 301). This template will also work for the Zeo Sleep Manager Pro+ and Zeo Sleep Manager Pro.

I have provided a second template for the Zeo Bedside, which has the snaps in a different location. Make sure you download the correct template for your device.

Before proceeding, print out the template. You may have to select "Actual Size" from the Print dialog box to prevent your computer from scaling the template. Check it against your Zeo device to make sure all the snaps are in the right positions.

Attachments

Step 3: Make the Front Piece

The part of the headband that rests against your forehead will be made out of the iron on patch. The iron on patch provides an easy way to seal the edges of finished sensor pad and gives it a clean look.

Cut out the template and then trace it onto the iron-on patch. Then carefully cut out the piece. I find that using the hole punch helps me to round out the corners of the openings and start my cuts, but you can do it with only scissors.

Variation: If you wish, you could use a sturdy piece of fabric instead of the iron on patch, but then you have to sew the whole thing together, or use staples to keep everything together. Your choice.

Step 4: Assembling the Back Piece

The back piece is what holds everything together, so choose a sturdy fabric. I purchased some black twill from my fabric store. You probably will have to buy way more than you will need, but it will be inexpensive (I paid $1.75 for a large piece).

1. Cut out the "Back" template and punch the three holes for the snaps. You should do this before attaching the template to the fabric.  Do this as precisely as you can, otherwise the snaps won't mate properly with the Zeo.

2. Cut a rectangular piece of fabric that is slightly larger than the template. Staple the template to the fabric as shown in the picture.

3. Punch out the four holes for the strap attachment. These holes need to go clear through the fabric.

4. Now, lift up the paper template and push three metal studs through the holes. If you used a 1/8 in hole punch, they should fit right through and hold snugly in place. The studs need to face away from the fabric.

5. Push the socket part onto the stud. This helps keep them in place on the paper template and provides a flat surface that will be helpful when you hammer in the prongs from the other side.

Step 5: Attach the Foam Pads

Turn over the back piece.

Now, using the front piece as a template, trace and cut out three foam pads out of double-sided foam tape. Stick the pads on the backing fabric. Make sure the front piece fits nicely around the foam pads.

Step 6:

You will now need to cut out the conductive fabric. The conductive fabric will cover the foam pads and will overlap the snaps. Each bit of conductive fabric will need to cover the pad and its respective snap, but NOT short out with the other pads or snaps.

1 - Cut the "Front + Back" template into three parts that surrounds each pad and its respective snap.

2 - Trace the three parts onto the conductive fabric.

3 - Cut out the three parts from the fabric and stick them on the foam pads. The double sided tape will hold them in place.

4 - If needed, trim the fabric so there is no chance of the pads shorting out. Be aware that the sensor pad is flexible, so give enough space between the pads to prevent shorts when you wear it.

Hint: The conductive fabric does not need to fully overlap the snaps, it is enough that it cover a part of the snap to make contact. If you cut it a bit short, it may help prevent the middle and right pads from touching and shorting out.

Step 7: Attach the Snaps

The metal studs are held onto the fabric by metal prongs which you hammer through the fabric from the opposite side.

The prongs not only hold the metal studs in place, but more crucially, they provide an electrical contact between the conductive fabric on the front and the metal studs in the back. Because of this, it is important that the prongs be bare metal.

Hint: When I bought my first set of fabric snaps, I found the metal prongs were painted white. Because of this, they did not make electrical contact from the conductive fabric on the front to the metal stud on the back. You can still use this type of prong, but you have to provide an alternative electrical path. One method which worked for me is to put a staple through the conductive fabric and backing fabric right beneath the stud, then drive the prongs on top of the staple. This presses the staple against the conductive fabric and the stud underneath, making reliable electrical bridge. This makes hammering the prongs a lot harder, but it can work if you don't have any other choice.

To drive the prongs through, place the sensor pad on a scrap piece of wood with the snaps facing down and the conductive fabric towards you. Now, place the prongs on top of the studs, with the sharp points facing down. You have to position them exactly on top of the studs, by feel. This is tricky. You can practice on a scrap piece of fabric. If you do this, try attaching the metal sockets rather than the studs, as you won't be using the sockets in this project.

Once you have the prongs positioned, hammer them down with a few solid strikes. The studs should now be firmly attached to the fabric backing.

Hint: If you have a multi-meter, you can check to make sure you have electrical contact between the conductive pads and the corresponding studs on the back. You can also check for an unintended short circuit between the pads.

You can now remove the staple and the paper template from the back of the sensor pad. The sockets that you snapped on the studs can be removed and discarded.

Step 8: Strap Attachment

The sensor pad is held against your forehead with a Velcro and elastic headband. You will use the original Zeo headband with your home-made sensor pad. The sensor pad has two anchors where you attach it to the headband. These anchors are short plastic tubes which are held to the sensor pad using a cord.

1 - Cut out two small pieces of heat shrink tubing or a plastic stir straw.

2 - Use your needle to thread a piece of black yarn or cord through the four holes in the fabric and through the tubing or straws.

3 - Tie off the loose ends in the front so that it forms a complete loop.

Hint: Make sure there isn't too much slack, but don't pull it so tight that it scrunches the fabric. The sensor pad needs to be able to lie flat.

Step 9: Putting It All Together...

Now flip the sensor pad over so that the conductive fabric is on top.

Position the front piece on top of the sensor pad and staple it in place. Make sure the glue side faces down. The staples serve to hold everything together while you seal the edges.

Now, using your clothes iron set on "Low" iron all around the edges. Make sure you get a good seal. You may need to experiment with the temperature, but don't go too high or it will damage the patch or conductive fabric.

You can press the edge of your iron against the four sides of each conductive pad to seal the conductive pads against the front piece.

Variation: If you don't have an iron, and you don't care how this looks, you can sew everything together, or simply use staples to hold everything together. My first prototype was made out of the conductive fabric, the metal snaps, paperboard and a lot of staples. It worked but it didn't look pretty.

Once you are done sealing the edges and pads, remove the staples. If you did this step well, it will all hold together nicely!

Step 10: Trim It and Presto!

Now, simply trim the backing fabric, and congratulations, you're all done!

You can now attach the headband to your sensor pad and snap the Zeo to the front.

Sleep well knowing you've saved a lot of money on replacement Zeo sensor pads!


DISCLAIMER: Although I have tested these sensors on my own Zeo device, you assume all risks for damage to your Zeo device by making and using these replacement sensors. I am NOT affiliated with Zeo Inc. in any way and did not consult with them in making this sensor. I make no guarantees about the performance of these handmade sensors vs the Zeo OEM sensors.

Step 11: Conclusions and Future Ideas

Although I have no way to truly compare these against the specifications of the originals, I have used these replacement sensor pads on my own Zeo and found that it was able to record an entire night's worth of sleep, just like the original sensor pads. I did not see any difference in the performance or accuracy of the readings, but this is just a subjective opinion.

The replacement sensor pads looks and feel like the originals. The pads in my replacements are slightly less soft and less puffy than in the genuine Zeo sensor pads, but nonetheless, I find them as comfortable to wear as the originals.

I am rather happy with how this project turned out. I am disappointed that Zeo Inc seems to have shut its doors, as I think the Zeo is a great product and I would like to see its continued development and enhancement. This Instructable is in no ways meant to detract from their business, should they find a way to resume operations.

If Zeo Inc does not make a comeback, I hope this Instructable inspires others to continue experimenting with these ideas. I suspect these sensor pads could be used as the foundation for other DIY projects related to sleep and brainwave sensing. Although perhaps a bit far-fetched, I would be delighted if someone with more skills than I could design and build DIY hardware to replicate or improve upon the functionality of the Zeo device itself!

Good luck and happy dreams! :)