Close
0%
0%

Remote Control Mini Blimp!

Mini blimp flies through hoops! Features 3 DC motors/ propellers, battery charging, and wireless communication.

Similar projects worth following
This project contains some DC motors, battery charging, sensors and data. I liter of helium lifts 1 gram, so there is a weight constraint in the circuitry. Exciting!

This is a remote control blimp which is controlled by joystick. 

Thanks to @oshpark for supporting this project.

One of the things I'll use this for is a blimp obstacle course. 

BlimpLi controller PCB measures approximately 110mm x 35mm and has 4 circuit modules.

  • Wireless communications using WiFi/ ESP8266 
  • Voltage regulator: VBatt (4.2V -3.7V) to 3.3V
  • Motor driver circuit for 3 motors 3.3V, 20mA
  • Battery charging circuit for 1-cell Li-Ion Polymer battery

- 4.33 kB - 04/23/2018 at 01:15

Download

sch - 628.93 kB - 04/23/2018 at 01:10

See BOM
Download

brd - 168.59 kB - 04/23/2018 at 01:10

Download

ino - 2.67 kB - 04/23/2018 at 01:10

Download

wifi_client_01.ino

Easy test pulled from Instructables

ino - 1.98 kB - 04/19/2018 at 19:37

Download

View all 16 files

  • 1 × MCP73812 Power Management ICs / Power Supply Support
  • 1 × AP2112 Power Management ICs / Linear Voltage Regulators and LDOs
  • 4 × capacitor 1uF
  • 3 × DC motors

  • Second Flight!

    Sophi Kravitz 05/21/2018 at 18:35 1 comment

  • Blimp User Controls (part 1)

    Sophi Kravitz 05/18/2018 at 16:22 0 comments

    I'm going with a joystick for the main controls because everyone knows how to use one. A joystick is primarily used for direction and speed, it should be received well as a participant interface.

    I need 6 commands minimum (up/ down/ left/ right/ forward/ back) and the joystick that I chose is made up of 4 microswitches, so only 4 controls. I love arcade buttons, so I decided to add 2 of those.

    Inside of the controller is an Adafruit Feather (has an ESP8266 on it) and a battery.

    I used Inventor to model this. Already realized that this rev 1 is missing holes for the battery charging and a reset switch. I also should have added screw holes on the bosses to make them less hollow. 

    I can fix these post print though :D

    and started printing last night. It looks good so far!

  • It flies, now what?

    Sophi Kravitz 04/23/2018 at 02:36 4 comments

    I'm pretty excited. The blimp flies and is as controllable as a large envelope full of helium in a drafty house can be ;)

    The blimp shown here is 24" diameter, 8" high.

    So what's different about this revision and why does it fly?

    • Motors are spinning super fast and drawing about 200mA each.
    • New motor drivers provide motors with battery voltage, but control voltage is separate, allowing for motors to get maximum power.
    • Board is 0.8mm thick and cut the weight of the PCB in half - thank you @oshpark!
    • Buck boost converter is slightly on the edge with allowing 1.3A, but is much more capable than the voltage regulator in earlier revisions.
    • Code has been revised so that there is no lag between control switch and motor.

    Gotchas

    I had a memory leak in which the ram was spinning down and causing the connection to drop. Turns out the libraries (2.4.1) provided for ESP8266WiFi have a bug. A down rev (2.4.0) fixed that problem, but it still took me a day to figure it out.

    Still todos

    • Evaluate battery draw with special wattmeter designed to look at single cell draw
    • The hardware is there to measure battery levels, add this to code and send signal when low.
    • There are still connection loss issues, hopefully adding error handling to code will address this.
    • FUN! Design controller for joystick and buttons. I'm envisioning a figure eight so that it fits nicely in the hand.
    • Test with 24" blimp when that arrives
    • Add ESP reset switch or button to gondola hardware
    • Add ESP reset switch of button to joystick hardware

    I found these docs helpful

    ESP8266 Modes + configuring

    ESP8266WiFi library definitions for Arduino

    ESP8266 libraries on github

  • Tiny motor thrust

    Sophi Kravitz 04/05/2018 at 17:06 1 comment

    Forgot to mention that I measured thrust the other day. This is a 3.7V motor at 40,000 rpm.

    Nontechnical way to describe thrust is the amount of force (unit grams) it takes to move the mass (blimp gondola) out of the way. 

    The real definition is the perpendicular force to the load measured in newtons, or the amount needed to accelerate 1 kilogram of mass at the rate of 1 meter per second per second. Source: wikipedia

    For later: https://www.rcbenchmark.com/learning-center/how-to-measure-a-brushless-motor-and-propeller-efficiency/

  • Blimp rev 3

    Sophi Kravitz 04/05/2018 at 01:01 4 comments

    Putting this PCB together has been quite a journey.

    While soldering QFNs I broke down and purchased a microscope and a hot air tool. The hot air tool was really cheap and is already loudly rattling after only a month in the shop. 

    I just received a board back from @oshpark that has some new accoutrements:

    • 0.8mm thickness
    • Tag Connect connections! (working!)
    • ADP2504 buck boost 
    • SOIC footprint motor drivers 

    It is all working well and it is the correct weight.

    Things to fix in next rev:

    • Connect PGND (pin 9) on motor drivers to ground (FACEPALM)
    • Connecting points for the motors are covered in solder mask (??)
    • Fix lag in comms between joystick and blimp (code? power problems? idk)
    • Measure current accurately with Astro Flight Wattmeter to get sense of battery curve

  • Gotchas WTF

    Sophi Kravitz 02/09/2018 at 17:50 7 comments

    I designed an intermediary board to test out a new buck-boost voltage regulator, new motor driver, and a tag connect cable. For those of you in the ESPxxx forum, this is v2 intermediary board with EN tied to VBATT.

    Here's the schematic, and the layout.

    I intend to run the board with a single cell Lithium battery no less than 3.6V.

    For testing, I am using a benchtop power supply (adjustable V, 3A) or a wallwart (5V, 1.6A).

    The new voltage regulator, ADP2504, can provide a current output (see diagram on page 6) of over 800mA at VIN 3.6V. The inductor is rated for 700mA. Capacitors are X5R type.

    Screenshot of ADP2504 schematic::

    So far, I have populated the board with the ADP and the ESP-12S.

    These two weird things are happening:

    With power input from benchtop > 4.6V, ESP is able to program and hold the program. Under 4.6V, it is iffy, meaning that the program does not run all the time. Same (expected) results with wallwart at 5V. 

    Current draw after ESP reset is less than 60mA, but sometimes (often at lower voltage) the current draw jumps up to as much as 210mA.

    Does anyone have an idea why this could be happening? 

    UPDATE: benchtop power supply is wonky and gives inconsistent readings, shuts off randomly, and probably puts out  inconsistent power. My best guess is that its constant current output is stuck on something not desirable. I've had it for over 8 years, so....

    To add to the gotchas:

    • New Macbook Pro is incompatible with anything FTDI (seriously WTF)
    • Fluke 16 measures a full 0.1V higher than the benchtop - no clue what is accurate now. 
    • 3VDC wall wart with indecipherable 2008 cell phone end now chopped off puts out something definitely not 3V!
    • Brand new air gun is making a horrible death rattle.

    *******************************************************************************************************************************************************

    The ESP8266 can source 12mA on each GPIO pin. Maximum Drive Capability spec page 15.

    Grabbed this from the forums:

    12mA per pin source

    20mA per pin sink

    Total: 12mA x 16 GPIO

  • Intermediate Step:: PCB to test Tag-connect, motor driver, and new buck-boost

    Sophi Kravitz 01/15/2018 at 15:02 0 comments

    I decided to go the route of a redesign on a couple of components. It was obvious that the voltage drop in the original voltage regulator was causing the regulator to be a steady 3.3V, especially as the single cell battery dropped below 3.7V. This caused the the ESP to reset occasionally. 

    I've chosen an Analog Devices buck-boost regulator to replace the AP2112. Yes it costs $1.57 more than something else, but this one has a lot of documentation, and is more likely to work the first time.

    After @Ted Yapo commented on my last log, I also realized that the fan motor driver I chose has a high voltage saturation need on the two outputs, limiting the power actually available to the motor itself. I've used fan drivers for other projects and like the simplicity of the part, but I redesigned the board to include an actual brushed motor driver.

    I made a square, somewhat spread-out PCB to test the new features, it's an intermediate step before putting all these new parts on the board and having no space to probe. 

    I sent it off last night to @oshpark's super swift service. It includes:

    • Tag Connect layout! >> this one I'm really excited about
    • New buck-boost >> already realized I forgot to put the thermal vias in
    • New motor driver >> only one, so the the buck-boost won't be getting that hot anyway :)
    • On-off linear switch (replaces annoying momentary)

  • Not enough lift = motor testing Saturday

    Sophi Kravitz 01/06/2018 at 18:17 16 comments

    My flight test showed me that my motors didn't have enough lift/ draw enough current/ rotate fast enough. I ordered several motors to test from Uxcell ranging from 13,000 rpms to 40,000 rpms.

    All the motors I bought have rpm ratings + voltage, but no kV rating.

    Motor kV (the rpm constant, not kilovolts) is the relationship between rpm and generated back emf (force). It's defined as the number of revolutions per minute (rpm) that the motor will turn when 1V is applied to the motor with no load. So rpms/ volt.

    A low kV (more winds, thinner wire) will have higher volts/ less amps/ higher torque so it can swing a larger propeller.

    A high kV (less winds, thicker wire) will have low volts/ higher amps/ lower torque for swinging a smaller propeller.

    The blimp is working a lot better. The motors are just not fast enough, nor are the propellers moving enough air to make enough of a difference. I put a 500 mA battery on it which is why now there are 5 balloons needed to hold it up :/ (I am afraid to weigh the gondola now). 

  • First flight

    Sophi Kravitz 12/24/2017 at 02:36 7 comments

    Tonight I got all the motors working and attached the blimp's gondola to a big purple cube filled with Helium. 

    There it is! The blimp sort of hovers and falls at the same time despite the motors turning as fast as they can. You can barely feel any lift from the poor little things! I've bought a lot of motors from random places, so now it's going to be time to figure out the right one with the right propeller.

    The motors I'm using pull 230 mA at max speed. The drivers I'm using spec a max of 70 mA, although I'm pulling 110 mA (and no heat, maybe I'm misreading something?). 

    I think the main problem is the battery though. It's one cell, 105 mA, so it just doesn't have enough ooomph. I also haven't measured the inrush current yet... could be that it's just killing the battery in one short second.

    Next steps:
    • Define best possible scenario for battery + motors (GAINING WEIGHT NOOOO)
    • Order new motors
    • Revisit motor drivers
    • Add 2 momentary buttons to controls for up/ down (save joystick for forward/ reverse/ left/ right)

  • Making two ESPs talk. One step closer.

    Sophi Kravitz 12/17/2017 at 23:41 4 comments

    Today I connected a Feather (Adafruit's HUZZAH + some other niceties) with a giant red joystick. The joystick switches ON-OFF via 4 microswitches rather than proportional movement. That's OK, the motor drivers I've started out deliver an ON-OFF signal as well. All 4 switches work and have been tested using the onboard LED on the ESP8266 (on the HUZZAH). 

    Working on making one ESP8266 (connected to joystick) talk to the other ESP8266 (connected to motors + blimp).  Found a project on Instructables to get started with. Now the motors are controlled by joystick :)

    There's some massive lag here, not really sure why. 

View all 18 project logs

Enjoy this project?

Share

Discussions

Adam Vadala-Roth wrote 04/05/2018 at 17:08 point

I already want one even though its not finished yet!!!!

  Are you sure? yes | no

Sophi Kravitz wrote 12/11/2017 at 03:55 point

I KNOW! Aren't they cool? :)

  Are you sure? yes | no

Anool Mahidharia wrote 12/04/2017 at 05:57 point

The battery charging circuit is dead weight to carry. Why not keep it separate/external ?

  Are you sure? yes | no

Sophi Kravitz wrote 12/04/2017 at 20:33 point

Hey Anool! I anticipate a lot of quick changes, so I want the battery to stay on the board. 

  Are you sure? yes | no

Anool Mahidharia wrote 12/05/2017 at 06:42 point

Gotcha!

  Are you sure? yes | no

Sophi Kravitz wrote 10/22/2017 at 22:05 point

:) I'm excited too, I think making the circuit light enough to float is going to be tough!

  Are you sure? yes | no

Anil Pattni wrote 10/22/2017 at 20:35 point

This is so cool, I've been wanting to make a R/C blimp for the longest time. :)

  Are you sure? yes | no

Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates