Sanchez Air/Babytooth 1s 3" ExpressLRS

By bulgogi19 on Jul 24, 2021

9  314  3

This is my first ever build after flying my moblite7 and Trashcan for a few months left me wanting something different. I based this off of availability of parts, some builds here and the ExpressLRS recommendations from some of the members of /r/multicopterbuilds. I'll do my best to make this write up for fellow first time builders. Overall, this build took me about 2-3 hours to complete from soldering components to betaflight/BLHeli setup. The fine pitch soldering will be the most challenging part for beginner builders, but isn't too challenging and will be great practice!

I think the EP2 Rx is a good choice dude to its small size and integrated ceramic antenna.

I'd like to find a better way to mount the VTX as its currently just double-side taped to the camera mount.

Build Steps

  1. Have your pin-out references ready to look at. I pulled the pin outs up on my computer for my FC, VTX and RX up for reference. Plenty of tutorials on how to make these connections correctly as it varies depending on what parts you're using.
  2. Dry fit FC and motors. I bolted up the FC and motors, measured the length of wire needed to make it to the pads (add 0.5-1" extra), cut + stripped the wires.
  3. Dry fit camera, VTX and receiver. Same process as with the motors. Pop your camera of choice into your canopy, get that mounted and figure out where you'd like everything to sit. Measure wire length and clip + strip. The Ant Nano came with a harness that had a plug on both sides so I had to cut one plug off to solder onto the AIO FC. I used double sided tape + kapton tape to mount and insulate my rx + vtx to the underside of the canopy.
  4. Detach everything from the frame and solder. Make sure you keep your wire runs tidy and add heat shrink to necessary connections before soldering. Solder on your battery connector of choice. I used a PH2.0 only because that's what my whoop batteries use.
  5. Test it all out. Now is a good time to test your connections if you aren't confident in your soldering ability. Take any props off motors, plug in a battery make sure all your indicator lights are on, check that your vtx binds to your goggles and has good camera feed and your rx binds to your tx (more on that later in the build). Plug your FC into BLHeli and check motor functionality in BLHeli or your flight configurator of your choice.
  6. Slap it all together! Almost done, bolt up your motors and FC and mount the rest of your stack (rx + vtx). I used a rubber band from some broccoli to make my battery mount as I've seen a lot of others do. I'll post a picture guide of how that voodoo works because it took me a good 5-10 minutes of twisting to figure it out lol.
  7. Config time! Make sure all your motors are rotating the correct direction (I went props out) and set all your configs to your preferred settings.
  8. Test flight !

    Some non-standard stuff to consider:

    • I used Kapton tape and heat shrink to insulate the stack boards from themselves and the frame. This is a high temp/non-conductive scotch tape-like material used for electronics, but electrical tape would also work for this purpose.
    • I had to grind 1mm off the included M2x4mm motor mounting bolts to keep the bolts out of the stators. If you don't have a dremel or something to trim the small bolts, I'd suggest getting some M2x3mm bolts (linked in the build under hardware)
    • I used 30AWG wire to solder the RX to the FC. A 50' spool and some heat shrink is cheap enough and useful to have.
    • This was my first experience with any exteral radio module and Express LRS was pretty easy to setup. I followed some video guides for flashing the newest OpenTX firmware onto my TX, as well as new ELRS firmware to the tx and rx modules (this can be done over wifi which is awesome).

TIPS FOR SOLDERING:

I have a good amount of fine pitch soldering skills and equipment from modding retro gaming consoles, but this isn't overly finnicky so it is good practice for those new to soldering. There are tons of videos on how to solder PCB's so I'd recommend a quick search for techniques. Some equipment I'd recommend:

  • Any adjustable soldering iron/soldering station with a small (2mm-3mm) chisel tip. I set my temp to 620F/325C
  • Some brass wool or a wet sponge to clean iron tip
  • 0.6mm 60/40 solder wire
  • 30 AWG wire for low amperage connections (RX,VTX,etc.)
  • Set of wire strippers that goes down to 30 AWG
  • No-clean flux. I use Kester 951, which is rosin-free and leaves no sticky residue, but it all serves the same purpose.
  • a set of "helping hands" to hold onto things

EDIT 7/27/21: Glad theres some interest in the build! I'll update the picture and write up with a few more details this afternoon.

Photos

Part List

Frame

Sanchez Air [Ultralight 3" Toothpick] (2 builds)
Cncdrones.com
$9.00

Flight Controller

DarwinFPV 15A 1-3s F411 Ultralight/Whoop AIO (9 builds)
Pyrodrone.com
$39.90

Motors

4 x Flywoo Robo 1202.5 11500Kv Micro Motor (3 builds)
Racedayquads.com
$43.96

Propellers

GEMFAN 3018 PROPS - (4CW + 4CCW) (31 builds)
Pyrodrone.com
$3.99

FPV Camera

2g CADDX ANT 1200TVL Global WDR OSD 1.8mm Ultra Light FPV Nano Camera 16:9 4:3 for RC FPV Tinywhoop Cinewhoop Toothpick Mobula6 (5 builds)
Aliexpress.com
$15.99

FPV Transmitter

PandaRC Nano 16x16 5.8GHz 25-400mW VTX - U.FL (10 builds)
Fpvcycle.com
$17.99

Receiver

Happymodel 2.4g ExpressLRS EP2 RX Receiver module (21 builds)
Pyrodrone.com
$13.49

Batteries

Happymodel Moblite7 Spare Part 1S 3.8V 650mAh 30C Lipo Lihv Battery PH2.0 Plug For FPV Racing RC Drone (2 builds)
Banggood.com
$15.99

Radio

Jumper T12 Plus Multi-protocol Radio Transmitter w/ JP4-in-1 RF Module Hall Sensor Gimbal Black (10 builds)
Banggood.com
$109.90

Goggles

Eachine EV800D 5.8GHz 40CH Diversity FPV Goggles with DVRDefault Title (23 builds)
Racedayquads.com
$99.99

Hardware

uxcell M2 x 3mm Full Thread Button Head Socket Cap Screw Silver Tone 50 Pcs
Amazon.com
$9.49

Misc Parts

NewBeeDrone BeeBrain V2 Color Camera Mount Whoop Canopy - Choose Your ColorBlack (21 builds)
Racedayquads.com
$2.99

Radio Module

Happymodel 2.4g ExpressLRS ELRS Micro TX module ES24TX (6 builds)
Pyrodrone.com
$28.99

Soldering Iron

Hakko FX888D-23BY, 599B-02 Soldering Station with 599B Tip Cleaner, Blue/Gold (17 builds)
Amazon.ca
$89.68
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Discussion

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GRIzmak   Aug 04, 2021  

Nice build. I have similar. I'm very curious about: what is the flight time that you achieve and what is the ready to fly weight?

bulgogi19   Aug 04, 2021 

All up weight is 60g (45g quad + 15g battery). I haven't clocked a ton of good flights to measure flight time since I'm still tuning, but I'd guess probably about 5-6 min acro and maybe about 8 min just cruising in angle.

GRIzmak   7 days ago 

That is nice. I'm getting around 2-4 min on 650mAh, but I'm pushing it hard. I have seen you are using a PH connector. Have you thought to use XT30 instead? Using XT30, I have noticed a significant reduction of voltage sag. You can gain an additional flight time on XT30. But you have to be careful soldering battery leads.

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