Upgraded AntiSpark Switch

Hi All,

Been working on my second electric longboard and wanted to upgrade the anti spark switch a bit. This is mostly the same to vedder’s antispark, with the changes being an additional FET, an additional resistor as per fechter’s 3b revision to the schematic (below) and an upgraded fuse, using the same fuse as used on JTAG’s BMS, available in many different ratings. The last two changes are larger trace sizes to better handle current and an option to supply 12V/5V power for an LED switch.

fechter schematic

My schematic Front of PCB Rear of PCB

Board dimensions are 42mm H x 63.25mm W and will be made using 2oz copper. The plan is to look over the design once more in the next day or so and order hardware right afterwards.

Feedback is welcome! If anyone sees anything wrong please let me know. I’ve also got a power distribution board in the works for supplying 12V and 5V loads as I have plans for lots of LED’s, as well as my own BMS, more info on all of that later.

Finally, a link to my github repo as well as a mention that all credit goes to vedder and fechter for the original hardware and schematic designs. https://github.com/msglazer/Anti-Spark_Switch


awesome stuff! you should sell these :slight_smile:

I’'d like to, I’ll definitely update with a BOM and costs in the next day or so. I want to test it first before I start selling it.

when I did my board I used Through-hole for both the input wires and the output wires. Seems to me that it has both mechanical and electrical advantages over soldering 10AWG wires to a pad on top of the board.

Otherwise your design looks good.


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I finished the BOM, pushed it to the github repo. It’s about ~$30 in components including PCB, cheaper as the buy quantity goes up. I’ll update again when I get hardware in hand.

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Been a while, got the boards in and assembled one. Guess I got a bad FET or something as it only dropped the voltage ~3-4 volts when on. I’ve ordered some more parts (thought I could get away with just one set of components, you can see how that turned out). If anyone sees anything wrong with the schematic let me know, its a direct copy but who knows.

Only slightly broke this one hah. While this one may have had a dead 12V zener, turns out I needed to have a load connected, everything worked great once I assembled a 2nd.

assembled board!

assembled with connector and switch.

I know some were interested in buying some (they’ll be approx $40-45ea), ill be making a sales thread, feel free to PM me if interested. Feel free to shoot me any questions.


Looks good but you will want to route the via from R1 to the “out +” pad to be sure you break the circuit if the fuse blows.

I’ve made that change for rev 1.1, good point though!

Hi emepror Nice design ! Do you plan to publish your gerber files for v1.1 with the R1 modification ? I would like to try your design but I would prefer to wait for this v1.1 fix.

Just updated the github repo.

@chaka Are the ones on your site complete or just the board? There isn’t any info on the product page.

They are complete with a switch. You need to add your connectors of choice.

Thanks !! But I could not find the new version. I can only see the master branch with the last commit in August :

Do you have this commit public ?

Same here. I see v1.0 w/ 2 month old updates.

Would love to try this v1.1 when available!

Everything looks up to date on my end, any luck now? I did make a couple changes today, i.e. switched smd pads to “handsolderable” versions, increased size of the connector solder pads, and a text change on the schematic.

Will definitely give this a go on my personal build. Kudos!

Hi all, the BOM was out of date and i’ve just fixed the issue. Hopefully no one ordered parts off the BOM before pretty much now (everything would be fine value wise).

Also, would a 60A fuse be more reasonable, or what value would people prefer on their builds.

I’m using 60A fuses for my pack, but it all depends on your battery specs. You are using LittleFuses right?

They have a decent selection of fuses. I’d say the most common ones are 40A(2P) 60A(3P) and 80A(4P) considering 18650 builds.

Yeah i’ve got a LittleFuse on my build. I’m placing an order for a small run and I want to try and cover the most options, probably going to get a 60A fuse.