Novena’s Hackable Bezel

When designing Novena, I had to balance budget against hackability. Plastic parts are cheap to produce, but the tools to mold them are very expensive and difficult to modify. Injection mold tooling cost for a conventional clamshell (two-body) laptop runs upwards of $250,000. In contrast, Novena’s single body design has a much lower tooling cost, making it feasible to amortize tooling costs over a smaller volume.

The decision to use flat sheet aluminum for the LCD bezel was also driven in part to reduce tooling costs. Production processing for aluminum can be done using CNC, virtually eliminating up-front tooling costs. Furthermore, aluminum has great hack value, as it can be cut, drilled, tapped, and bent with entry-level tools. This workability means end users can easily add connectors, buttons, sensors, and indicators to the LCD bezel. Users can even design in a custom LCD panel, since there’s almost no setup cost for machining aluminum.

One of my first mods to the bezel is a set of 3D-printed retainers, custom designed to work with my preferred keyboard. The retainers screw into a set of tapped M2.5 mounting holes around the periphery of the LCD.

The idea is that the retainers hold my keyboard against the LCD bezel when transporting the laptop, protecting the LCD from impact damage while making it a little more convenient for travel.

Such an easily customizable bezel means a limitless combination of keyboards and LCDs can be supported without requiring expensive modifications to injection molding tools.

The flat design also means it’s easy to laser-cut a bezel using other materials. Here’s an example made out of clear acrylic. The acrylic version looks quite pretty, although as a material acrylic is much softer and less durable than aluminum.

I also added a notch on the bottom part of the bezel to accommodate breakout boards plugged into the FPGA expansion connector.

The low up-front cost to modify and customize the bezel enables experimentation and serendipitous hacks. I’m looking forward to seeing what other Novena users do with their bezels!

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13 Responses to “Novena’s Hackable Bezel”

  1. Do you have a good source for those keyboards outside eBay? Lenovo does not appear to be selling them any longer.

  2. Zane says:

    Nice hack, but how lond did it took you to customize and how much it costed you if you don’t mind telling to your viewers ?

    • bunnie says:

      Designing the keyboard retainers took an afternoon. The toughest part was modelling the keyboard, actually, because it has a sloped base and I had to use calipers to extract the height at a few points and create a lofted shape to model the slope accurately; I really wanted the retainers to fit like a glove. Once I had a model of the keyboard, it was very quick to create the retainers, since I could offset the surface and cut the solid body of the retainers with that surface.

      The retainers were then exported to STL and printed on a Form1, which took about 3 hours. It was 25ml of resin for the three pieces including support material, so the material cost was about $2.50. To be fair, I had to print a second iteration of the retainers because the first one’s fit was too tight, so if you wanted to include the cost of iteration the overall material cost was $5.00. Also to be totally fair, I get my resin at a discount as I was a backer of the Form1 on Kickstarter, so every month I get a coupon for one bottle of discounted resin. If you don’t have the discount it might cost you about $3 or so to print the same thing.

      The acrylic bezel was very fast to design. I extracted the flat pattern from the STL CAD file by creating a solidworks drawing and exporting the view. Modifying the CAD to add a notch was also very fast, maybe thirty seconds of work. Once I had the drawing I sent it over to my Full Spectrum hobby laser cutter, which took about 3-4 minutes to cut. I got it on the first try. The material cost of the acrylic sheet, which was 18″x24″, was about SG$5.00, or about US$4.00. It takes longer to install the bezel (about a dozen screws) than it does to design and cut the bezel.

  3. steveM2 says:

    Nice hack!
    BTW, are there any reasons you didn’t use screws like these ones for the case:
    I feel they would be less aggressive than the cylindrical ones you have on every photo/video of the novena.

    • bunnie says:

      Buttonhead screws are nice too, but I personally like the look of the socket cap screws. It’s reminiscent of the machine shop at the robotics lab I used to work in.

  4. Taniwha says:

    while we’re talking about keyboards I’m after a non-tracpoint (ie center trackpad) keyboard for my Novena when it shows up (I need for for RSI reasons) – I’ve been on the lookout for something like this for years and never really would anything that was both compact and not utterly cheap (extra points for a 3-button trackpad)

    I’m going to order one off these to see if it will fit the bill, I’ll report back:

    any other pointers would be great

  5. Taniwha says:

    So I got one, looks like it works great with linux, comes with a USB dongle (not bluetooth) it’s solid and will probably work for me

    The dongle can be pulled apart and made tine and pushed inside on to the internal USB – figuring out how to power it off in ‘flight mode’ will be interesting – Bunny how are you doing this for wifi?

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  7. Raja says:

    Congratulations Bunny!!
    This is really exciting product.

    Where can i find the case design files?

    I like the laptop case.
    I want to use my old laptop mother board,monitor and fit that into new body like Novea.Please advse me the best way to do it at home.

  8. Hi Bunnie,
    Is there any chance the SDL or STP of your keyboard retainer could make it onto your github or the Novena wiki? Apologies if it’s already there, I’ve had a reasonably diligent look.

    I’ve gone with the same Lenovo bluetooth keyboard because, well, it’s a known good. If you can spare me an afternoon with calipers and the hackerstapace’s 3d printer that would be cool.

    Once again, thanks to you and Xobs for bringing the Novena to the world. It’s an important device for our time, I wish I’d ordered 10 of them.

    Ian Mack