Vb_driver - a variable brightness upgrade for older grids

project status: in progress


  • interest gathering / order number estimates [in progress]
  • final driver PCB revision. [done, ordered]
  • programming and test jig [done, ordered]
  • driver PCB fabrication & assembly [to do]
  • firmwares modifying & testing [to do]
  • shopify / ordering system [to do]
  • shipping [to do]
  • 40h kit / Arduinome adapter PCB [done]


  • original series [done]
  • greyscale
  • 40h
  • other sub revisions?
  • arduinome

4-level brightness grid upgrades - not possible with this hardware. may look into in the future.

original post:


over the last year and a half (part time) i have developed a variable brightness upgrade for older monome grid devices. the upgrade is a soic sized max7219/7221 replacement, and a firmware upgrade for the monome grid logic board.

firmware for the original series grids is complete. all serial led functions.
grayscale and even 40h firmwares should also be doable.

an adapter board for kits and arduinomes using the dip package max7219/7221 can also be created, if there is interest.

the upgrade would require the following equipment:

  • soldering iron

    • good temperature control
    • 1 larger tip for desoldering
    • 1 finer tip for soldering vb_driver
  • tweezers

  • multimeter

  • flux (tacky), noclean

  • isopropyl alcohol (or an ultrasonic cleaner)

  • something to scrub/wipe the alcohol with (old toothbrush, paper towels)

  • solder (lead free for keeping with monome standards)

  • atmel dfu programmer for upgrading the logic board

  • 1 vb_driver per 8x8 monome grid.

    • 64 = 1
    • 128 = 2
    • 256 = 4
    • 512 = 8

these are the simplified steps to complete the upgrade:

  • disassembly

  • desolder the MAX7219
    i used the following method:

  • clean / inspect
    scrub the boards with isopropal alcohol to remove the sticky residue left behind from the flux. you may need to do this several times. alternatively use an ultrasonic cleaner. or any other appropriate method you find.

    check the whole PCB for solder balls. using the above desoldering method theres a high chance small solder balls are formed and can end up just about anywhere on the PCB. i’ve had some bridge pins on the keypad multiplexers. this lead to (temporarily) dead rows / random button presses.

  • solder vb_driver
    carefully align the vb_driver in place of the max7219 and in the correct orientation. you need to get this right first time. i’ve had extremely low success desoldering vb_driver without damaging the castellated vias on its sides.

    solder/tack one of the castellated vias, check alignment, solder one on the opposite side, check alignment, then solder the rest.

  • clean / test / Inspect
    clean again.

    use the multimeter to test for continuity between adjacent connections on the driver. test that each connection has continuity to another connected part of the board. ie the ribbon cable connector

    again inspect the PCB for solder balls.

  • upgrade the logic board firmware
    Makefile for avrdude:
    cd (firmware directory)
    make pro

  • test
    before putting everything back together its a good idea to connect everything up and run through some tests to ensure the driver, and the keypads are both working correctly.

  • reassemble
    disassembly instructions in reverse

these instructions are rather brief and will be expanded on in time.

to be confirmed, but likely around US$50 per vb_driver shipped from New Zealand.

i will most likely assemble these myself. if there is a massive amount of interest i may move to commercial fabrication. this may change the price.

if you’re interested, comment below, let me know what size grid(s) you would potentially order for.
i will use this information for estimating an initial run, which i will offer via shopify when built.

this upgrade is somewhat complex, and not beginner friendly.

suggest practicing desoldering on something else (less important) before taking an iron to your grid if you’ve never done it before. or find someone in your area to do it… people could offer / request upgrade services here (or in another thread).

i will probably open source the hardware design and driver firmware at some point.

more info to come.


This might be silly, but would you consider accepting shipping grids your way for a complete assembly? I am not sure if my soldering is steady enough to do this myself. My location is Oslo, Norway. 64 series grid.


Very cool! Would be interested when grayscale is supported :+1:


Super interested in upgrading my 256 walnut grid. Not sure if I have the skills to do it for myself, but definitely interested

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Definitely interested although I think it’s on the edge of my skills.

Edit: 256 grid.

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This is so good! Right now I am listening to a radio feature about an enterprise, repairing, maintaining and updating old electronics. Good spirit – good philosophy! Thumbs up and hats off!

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Great job!

Very very tempted to upgrade my walnut 256 which is not really used anymore, it would look great with VB.

Edit: confirming interest for a 256 (4 units)

definitely interested.

I have 1 original 40h kit grid plus 2 more 40h boards driving arduinome sized keypads.

upgrading these to varibright would make them a lot more useful.

I have a 2007-era walnut 64 which I’d love to get varibright on, but this level of soldering expertise is way beyond me.

If there’s a way to ship my grid / logic board to someone capable of upgrading it (either directly to you in NZ, or to someone else doing a bulk order of vb_drivers closer to the UK) then I’d be very interested.

As others have said, great to see this kind of modification happening!

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Oh man, I’ve been waiting for this post since you teased it a while back.

Will upgraded grids be able to work with ansible, as I believe older grids currently don’t?

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This looks really great! Would these drivers increase the maximum brightness of a 4 stage variable brightness grid? The picture you posted looks like it might :smiley:


wow. this is amazing.
by beautiful walnut 128 has been just sitting on a shelf ever since the slim metal grid showed up.


I’m in for a grayscale 64 and 128 !


Very interesting. What package size is that replacement MAX7219?

I might be able to offer my soldering services for chip replacements in the US.


i would prefer if we can find someone closer (wherever you are), shipping costs, possible import duty & GST in NZ (not sure if this applies to servicing, will need to investigate), plus i don’t really wanna add to each devices carbon footprint too much.

suggest adding you location and grid size to your post to help the process along.

that said, I can probably service devices in NZ.

I may have over-exaggerated this point. its not really more difficult than a 1.27mm pitched IC. the de-soldering is a little tricky at first though.

this was my intention, and to not send too much of the old device to the landfill. it certainly would have been easier to just redesign the whole keypad PCB. but would be less universal across devices, more expensive, and wasteful.

it should work with everything the current devices do.

no idea, i’ve never seen the inside of those. i presume they are using a different driver… we can look into it.

technically these will be slightly dimmer than the originals. i don’t think its noticeable though. the maximum output current is about 90% of the max7219 i think. i will confirm this.

the package is a 10 x 15mm SOIC 1.27mm pitch. it ended up being around 1mm longer to one end than the max7219, a fact that saddens me very much. i’ll share some photos of the driver soon.


Very interested.

I have two grayscale 128s, and I’m in Southern California.

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I would absolutely be interested in this service. Name your price and take my money lol



Totally interested in this! What an amazing project.

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Interested. Grayscale 128!

Edit: Located in Minnesota, USA

I am definitely interested for my gs128, and if that goes well, possibly also for my 40h a bit later. Based in EU, and comfortable with a soldering iron and surface mount soldering

Delayed edit: yes, I should just go ahead and do the 40h too at the same time, so 1x for gs128, 1x for original 40h, if that will be supported