Technician Gimmick

That's really cool. Now that I think about it, I had never really tested to see what level I had discharged the LiPo batteries to. Instead, I installed a limit module that was pre-made for lipo batteries. It automatically shuts off power before the battery is damaged.

I like the sensor you got for measuring speed and ammo count. I didn't know they even made those.

 - TG

Looking really cool! Do you have any video of it in action?

Also, do you have any kind of safety preventing your Lipo from being drained too far, or do you just re-charge regularly enough that you don't run into that issue?

I'm looking into continuing the Gryphon over the next couple months. When I have something note worthy accomplished, I'll be sure to post onto my old Gryphon post.

Have fun Nerfing!

- Technician Gimmick

Thank you Limmers. It was really a fun project when I had worked on it. I'm glad it served as some inspiration for your project!

I will be following your project to see how it goes for you.

Have Fun!

- Technician Gimmick

This continues to be my spare time hobby.  I've almost finished a home made reflow oven so that I might begin making my own PCBs. But the project is moving slow.  For that I'm sorry everyone, I know many of you have expressed interest in this endeavor.  I do intend to complete it, and I will contact you all when it is completed.

Thank you all!  And enjoy playing Nerf!

 - Technician Gimmick

Here's an enhancement for you - https://code.google....SecretVoltmeterIf you use the right Atmega chip, then you can find out what the internal voltage is, and from that, you can work out what the current charge state of your LiPo is, without needing additional circuitry.  Personally, I will be powering my nano from the JST balance plug, full voltage, onto the unregulated power pin.

 

Thats cool, I had no idea that the arduino could do that.  But if I'm not mistaken, it will only show you the 5v or 3.3v rail that the Atmega328 is running on.  If you are using an S3 (3 Cell) LiPo battery, then full voltage will be 11.1v.  If you run off of any of fewer cells though, you'll still only get as close as 7.4v, or 3.4v.  I suppose you could run the MCU off of a single cell of the lipo, but there are a few things you need to keep in mind.

1. A fully charged lipo cell runs at 4.2v, and at maximum safe discharge, it will go to down to 3v.  4.2v may be more than a 3.3v MCU can handle.  And 3v may be less than a 5v can handle.

2. Discharging a lipo unevenly (more load on some cells than others) is bad for your lipo.  And if you are only measuring one or two cells to determine the battery's overall power level, then you'll be estimating the unmeasured cell's power level.  (i.e. if cell one is at half discharge, then I'm assuming cells 2 and 3 are as well.)  And while that may work at first, because of the uneven load distribution, you will eventually get faulty readings as the cells deteriorate.

As far as I know, you'll have to regulate the power down from 11.1v to 5v or 3.3v, but if it is regulated, you won't know if the battery is loosing power or not based on the power to the MCU.

If I'm not understanding what you're saying, please let me know because my current understanding says I need to know the voltage of each cell of the lipo individually, in order to properly protect the battery from over discharge.  Hence the circuitry to measure the battery's power.

The rest of your project sounds great though.  Will you be making a project post on Nerf Haven?