DAVEga: Battery monitor, odometer, speedometer

I think separating the 2 pieces, while it increases the level of complication, lowes the risk of damage to half the unit and makes the enclosure a lot smaller.

Ideally I need the full body measurements of the assembled unit, and the individual halves.

If you can PM me the BOM I can order the pieces and do the assembly here. Or if you have an extra you can loan me Ill send it back when I’m done.


In fact, it doesn’t really make it a lot smaller unless you cut or bend the pins:

The display can be purchased on Amazon for a more expensive price, but I guess then you won’t need to wait for it for a month.

Other than that, the chip is the bulkiest part. It’s the atmega 328 in the DIP package. I believe the vertical size is the same as any other DIP package MCU. If you cut a piece of perfboard in the same size as the display and put both the chip and the display on it, you should have a good idea about the assembled dimensions.

I currently only have a single prototype on a perfboard. It needs at least one tweak. The 4 pins used for connecting to the VESC need to be replaced with a 90 degrees 4 pin JST connector that I will have to order since I’m unable to get it locally. The pins don’t work. The cable keeps sliding off.

I’m going to order professionally manufactured PCBs and put together assembly kits that I can send out to anyone interested for the cost of the parts and shipping. I can send one to you then as well. It will take a while though since I will be ordering from China to keep the costs down. If you’re eager to start designing the enclosure in the meantime, I believe the display is the most critical part to have for that.


I’ll order the display so I can get started. Id love to have one of the manufactured PCB’s and assembly kits as well.

Do you have a link to the atmega 328 in the DIP package? I’ll order one of those as well.


Looks pretty similar to this.

I have mine on order just waiting for him to finish them and ship em out.

That was also the way I planned to use. At first, I thought about using FAULT_CODE_UNDERVOLTAGE (= power switch off), but it’s a bit dangerous writing EEPROM whike powering down…

Alright, guys. Seems like there’s at least a few people who’d like one of these gadgets. I’m going to order the parts and I need to know at least a rough number. Anyone interested, please like this post. I mean this particular post (not the first post in the thread). The cost should be around $10 + shipping. I won’t be making money on this. I’ll only ask you for what I paid for the parts and the shipping. Please note that the gadget hasn’t gone through much testing, so please only sign up for the first batch if you don’t mind being a guinea pig. I’ll do my best to fix problems as they come up. The gadget assembly will require some easy DIP soldering. I will try to put together detailed instructions. Anyone should be able to do it. I can send a few assembled as well. I like to solder. It’s very relaxing. :slight_smile:

Please don’t like this post if you don’t want the gadget kit. :smile:


Wow for $10 plus shipping I’m down. I can experiment with this and maybe use it on my second board.

I would also be down for one :slight_smile:

Oh that one looks very nice. I wasn’t aware of it. Well, competition is always good. :slight_smile:


Here’s one that I quickly found on Amazon.

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I guess we don’t need 2 people designing the same thing

Just when I run out of likes for the day :sob:

I think we had the same idea about this. I save after each 100 meters traveled (configurable) or whenever the board comes to a stop. In the latter case, I also check that at least X seconds elapsed since the last save. This is to prevent too frequent EEPROM writes in case the erpm indicate stop-go-stop-go sequences in a very quick succession for whatever reason (this is just a safeguard; I haven’t really noticed that to happen when testing).

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I’m still down for buying your kit and putting it together my self maybe I’ll even like it better than the Photon one.

Awesome, Ill get them ordered.

I would consider a higher cost. You’ll have to manage a ton of questions, remarks, support, especially every VESC FW update. That deserves a bit more money :wink:


I put the request for a name through a long and arduous testing panel of marketing experts and the answer was unanimous. Dave.

It came to me in 3 seconds while drinking a coffee and watching someone wash my car, because while you’re out there creating amazing content for our community and adding real value to this forum I’m too lazy to even wash my own car :rofl:

I think this qualifies me though.


i’d like one as well, where are you based?

also, for those running mono drives with bt module connected to uart, the vesc gauge would have to take its place, right?

for dual drives, plug the gauge into the controller without bt installed?

I would assume so, but there are some programming changes you have to make to get both bluetooth devices to work. I don’t remember off the top of my head but Ill look it up and post it.

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That could be, I saw a lot of people doing something similar using a big capacitor on the arduino input so it has time to complete the save, but I guess it only works if you are using an external 5v dc dc converter or the cap may have to be a lot bigger to keep both the logic of both VESC’s on for enough time

Could be, at least in my head a lot less writes will happen doing just when stopping I remember seeing that on FOC the erpm does not goes to zero when stoped, it swings a little bit, may need to pay atention to that

But either way, using your method you would need at least 10000 km to reach the eeprom limit, and from a test I saw they last way more than that