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I recently purchased a Walkera Rodeo 150 Racing Drone. I'm not a fan of RTF (ready-to-fly) model aircraft and prefer to build my own. But this little $220 USD Quadcopter looked so cool I took the plunge.

beauty1_1000.jpg

I purchased the RTF version with the Devo 7 R/C transmitter. The last thing I need is another R/C controller and so I wanted to get the version without the Devo 7 radio. But the eBay seller was offering the full RTF package with an extra flight battery for a very fair price. Sold!

Out of the box it flies great. It is really a blast and the small size is perfect for my backyard "race" course.

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But I'm not here to report another me-too review. The web/youtube is overflowing with those already. Instead I'm here to talk about hacking this thing. Sure, it is a blast to fly and is already equipped with an FPV camera. You may think only a fool would try to hack it with the risk of bricking the little fellow. Well, you must be new to this forum because I'm a relentless hacking fool. :)

I have some ideas that are being considered. How about adding an OSD (micro MinimOSD)? Or addressable RGB LED's that change color depending on the flight mode or alarm state? Or perhaps altitude hold (barometer sensor)? Yes I know what you're thinking -- these are silly features for a racing drone. But let's be honest, this is a consumer marketed product that would be a poor choice to enter into a competitive race. It is really just a sexy looking plastic toy that flies moderately fast and is stable enough for beginners. So adding fluff features would not be a sin.

To investigate the possibility of hacking the first thing on the to-do list is to perform some simple exploring. It's important to know some details about the flight controller hardware. Fortunately its firmware is a variant of CleanFlight; So we can do some digging with the CleanFlight configurator app.

CleanFlight reports this:
  Board = SRF3
  Identifier = F150
  Version 0.1.3

cleanflight.jpg

 

The "SRF3" board ID means that the hardware is based on the SPRacingF3 flight controller. That is useful information since it helps with understanding the possible hardware I/O options and supported software features. So far so good.

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With that out of the way it's time to look at the flight controller hardware. The top canopy was removed to expose the controller. The 2.4GHz R/C receiver and 5.8GHz FPV video transmitter (vTx) are in the same area. It's a tight fit in there with little room to add an OSD. This is not great news, but maybe it is possible to squeeze one in.

rodeo150_top_cvr1_1200.jpg

 

 

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By the way, from the online discussions at rcgroups it seems I may have been the first to get the top cover off. This task should be easy but Walkera went out of their way to make it challenging. In case it helps out, here are the instructions to do it (See photo):

1. Remove antenna.
2. Remove 1.5mm hex screw (1 place) on top cover, location 2.
3. Remove star (+) screw, left and right sides (2 places), location 3.
4. Gently pry at the top cover seem at location 4 area. The case should start to separate. Just a small gap, do not attempt to remove the cover yet.
5. Continue to separate the case along location 5 (on left and right sides). Just open a small gap, do not attempt to remove the cover.
6. With the top case seam now slightly opened, use a flat tool to pry the top-front center trim at location 6 (see photo). This will require some effort but can be accomplished without harming the plastics. At the same time, press down on the front end of the vTx cover to help increase the gap between these two keyed covers. The goal is to get sufficient space between them so that the vTx cover can slip out of the keyed peg that is hiding in there.


Warning: If you muscle the disassembly you will dent/scratch/disfigure your plastic parts. Go slow, have patience!

rodeo150_top_cvr2_800.jpg

Edited by Mr.RC-Cam
Edited step 6.
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To remove the FC (flight controller) the vTx board must come out first. You'll need a small star (+) screwdriver and 1.5mm hex tool. On the bottom side of the FC is a FlexCircuit ribbon cable. This cable is locked in the connector by a retaining bail. Carefully lift it up to unlock the cable and slide it out.

I didn't take any pictures of the FC but here is a stock photo from Walkera:

flightController1_500.jpg

 

Now the bad news. Unlike you would find with a traditional FC, the PCB designer did not bother to break out all the CPU's I/O pins to convenient pads or connectors. So adding hardware features will probably require SMD soldering to the CPU's fine pitch pins. Not a problem for me, but will be a deal breaker for most hackers.

 

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But there is some good news. The 6-pin connector near the USB jack is the i2c port. The connector is a JST micro 1.25mm type. My o-scope determined that the connector's pinout is as follows:
Pin 1: I2C Clock (3.3V logic)
Pin 2: +5V
Pin 3: RX2
Pin 4: TX2
Pin 5: GND
Pin 6: i2c Data (3.3V logic)

{* Pin numbering begins towards the front of the model}

Easy access to the i2c signals will make adding a barometer for altitude hold a simpler task. This feature is a low priority but being relatively effortless to try I might give it a go.

 

Edited by Mr.RC-Cam
Added RX2 & TX2 to pinout
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At this point I've ordered a micro minimOSD board, some WS2812B addressable LEDs, and baro sensor. All from China, so I don't expect to see them for a few weeks. In the meantime I'm going to blast around my little race course with the stock model. As they say, I'll fly it like I stole it!

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I created a 3D printed camera mount that goes over the canopy. Total weight with a 808 keychain HD camera is only 18 grams. I did a casual flight with it and the little Rodeo 150 didn't have any problems hauling the extra baggage. Flight duration is shorter but still plenty of run-time to have some fun.

w150_cam808_1_800.jpg

 

Here is a rendering of the 3D printed mount (no-angle "Explorer" version):

w150_cam_mtg1_800.jpg

Here's the STL file for the explorer mount: cam_mtg1.stl


I also created a "Racing" version (808 camera tilted up 15 degrees).

w150_cam808_race1_800.jpg

Here's the STL file for the racing mount: cam808_mtg2.stl
When you print the race mount be sure to add temporary support structures. ABS plastic should be scaled 101% to account for shrinkage.


Unfortunately my 808 is an old version 6 with a very narrow 70 deg FOV. So I'm not happy with the viewable image in the recorded video. But the test flight demonstrated that adding a small HD camera is practical. This little Quadcopter can be just like its big brothers. :)

 

 

Although I don't have one I think a 808 version #16 camera with lens D (120 deg FOV) would be the best choice for recording aerial videos on the Rodeo. It is available on eBay for about $45 USD. Beware of cheaper fakes!

Here's a 808 #16 Lens comparison video that I found on YouTube:

 

Edited by Mr.RC-Cam
Added 3D rendering of race mount.

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Two different baro sensor (for altitude hold mod) are on their way to me. I ordered a BMP280 ($2) and a MS5611 ($10). The MS5611 sensor has the best precision but the BMP280 is on a smaller pcboard that has a much better chance of fitting in Rodeo's limited free space.

bmp280_pcb1_450.jpgms5611_pcb1_500.jpg

But at this point I needed to know which (if any) of these two baro sensors are supported in the Cleanflight firmware version that Walkera created. That is because Walkera has edited the source code and created a build configuration named "F150".  The source code to this configuration has not been released to the public (but Walkera must do this per the terms of the open source license). So for now we'll need to make educated guesses on the sensors it supports.

To determine which baro sensor is supported I began by reviewing the code for the stock SRF3 build that is used on the original SPRacingF3 flight control board. I believe Walkera used this hardware to create their custom flight controller, but this is just a hunch. The stock code expects a MS5611 baro sensor and also a Mag sensor. Neither of these are used on the Rodeo 150 so attempts to communicate with them would cause an i2c error. This knowledge is key to determining which baro sensor is supported.

By a process of elimination I determined that the MS5611 is supported. It also seems that Walkera enabled the BMP280 baro sensor in their firmware version. So at this point it appears I can use either sensor. Cool!

How did I determine this? Here's how I did it.

1. Launch Cleanflight configurator & connect to the Rodeo 150.

2. At the bottom of the screen is the i2c error count status. Should be 0 if all sensors are present. But with the default settings it has 4 errors. Ok, that hints we have some missing sensors.

3. We are not interested in a missing magnetic sensor. So I used the CLI (command line interface) and disabled all communication to the mag hardware. The CLI command to disable it is SET mag_hardware=1.

After saving the new hardware setting the i2c error count status is reduced to 2. The error count reduction tells me that two different mag sensors are supported by the Rodeo. The remaining error count (2) hints that up to two different baro sensors are supported.

4. Next I disabled all attempted baro sensor communication. The CLI command is SET baro_hardware=1. The i2c error count status was reduced to 0. This confirmed that I was on the right track.

5. Next I reviewed the baroHardware code in the stock SPRacing initialisation.c source file. I used this function's case statement to predict which baro sensor is supported in the Rodeo firmware. For now I assumed they did not modify the baroHardware code section. If Walkera did not touch this code then my predictions should prove to be true.

Before testing I wrote down my predictions, which were as follows:
If BMP280 is not supported the i2C count would be +1.
If MS5611 is not supported then the i2C count would be +1.

The order that the sensors are enabled in the CLI is important because the case statements are fall-through. So when any baro sensor is enabled for communication the sensors defined after it (in the source code) are also enabled for communication.

Using the CLI function, I issued the command to set the hardware to use a BMP280 (SET baro_hardware=4). The i2C error count increased from 0 to 1. So this missing sensor is supported.

Next I set set the hardware to use a BMP085 (SET baro_hardware=2). The i2C error count did not change so this sensor is not supported.

Finally I set it to use the MS5611 (SET baro_hardware=3). The i2C error count increased from 1 to 2. So this missing sensor is supported.

6. Before ending the test the original CLI settings were restored: SET mag_hardware=0, SET baro_hardware=0, save.

When the sensors show up I can determine if my baro predictions are accurate. I feel decently confident about it, but sometimes things don't go as expected. :)

 

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I'm not a big fan of the Rodeo FPV camera's soft focus and color rendering. But I like its FOV (field of view) which is spec'd as 110 degrees. It does well in low light conditions too. BTW, it is a PAL camera, not NTSC.

For my first attempt at achieving better FPV video quality I installed a different micro camera. I purchased the NTSC 600TVL micro camera from BangGood but it is available from a long list of China based sellers and eBay.

CMOS-600TVL1.jpg

 

This camera is advertised by every seller as 600TVL. But I've heard that it is officially a 420TVL. Also, many suppliers claim it has a 110 or 120 degree lens. But the real FOV is about 170 degrees, which is much wider than I normally prefer for FPV.

For lowest weight I removed the existing wires and its integrated microphone. A short 35AWG cable was created that has a 3-Pin 1.25mm micro connector that is identical to the existing camera's connector (got it on eBay). Now I can simply disconnect the stock camera and plug the new camera in. Final weight was exactly the same as the original camera (2.5g).

I wanted the new camera to mount exactly the same as the original. A custom designed 3D printed mounting bracket with pivot axle took care of this.

cmos_cam2_1000.jpg

cmos_cam3_1000.jpg


Here is the 3D printer STL file: walkera_cam_mtg1.stl

The new camera goes in the Walkera Rodeo just like the original. The articulation feature works the same too. Camera transplant is a success!

cmos_cam1_1000.jpg

 

This camera has an adjustable focus (something Walkera did not permit on their camera) . I tweaked it for best far field image quality. Here's a video of the camera's maiden test flight.

My HMDVR recorder substantially reduces the image quality so keep in mind that my live video looks much better.

I have mixed feelings about this camera mod. I like its improved focus and better colors. But I'm not enjoying the über wide FOV. Unfortunately I cannot find a source for a compatible IR blocked 2.1mm lens, which is what I'd like to use instead. Maybe the final decision will involve a coin toss.

 

Edited by Mr.RC-Cam
Added STL file.
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I've been using Alkaline batteries in the Walkera Devo 7 controller that is packaged with the RTF Rodeo 150. I was surprised to find that they don't last long. So it makes sense to install rechargeable cells. But rather than use old-school NiMH I'd prefer a 2S or 3S LiPO. But I didn't know if either would be compatible with the Devo 7. Time to do some investigation.

Here's what I found after powering the Devo 7 from my lab power supply:
Full Pack Voltage (4 bars): 12V
Empty Pack Voltage (0 bars): 9V
LV Alarm Buzzer: 8.1V
Automatic Shut-Off: 7.8V
Current at 9V - 12V: 220mA (back light on).
Current at Standby/Off: 12uA


Bummer. A 2S (7.4V) LiPO won't work because it is below the shut off voltage. And the LV Alarm Buzzer threshold is too low for a 3S LiPO. Not what I was hoping for; I'll have to use a 8-cell (9.6V) NiMH or NICD pack instead.

EDIT/UPDATE: I installed 2500mAH NiMH batteries (8 pcs, 9.6V) in the Devo 7. When fully charged only 3 bars are shown on the battery status display instead of 4 bars seen with fresh Alkalines. The built-in charger requires a 12V regulated wall wart supply (50mA minimum) with 2.1mm x 5.5mm plug (center positive). The Devo 7 limits the charge current to about 35mA. So charge time for an exhausted battery pack is about 72 hours. Faster charge times requires removing the cells and charging in an external charger.
 


It still bothered me that the Devo 7 draws a lot of current. My opinion is that 220mA is too much for a 12V "low power" RF design. Maybe we can fix that? So time to void the warranty and open it up.

A quick glance at the Devo's PCB was all it took. They used a 5V linear voltage regulator (LM7805) in the design. That means with fresh alkaline batteries there's 1.5 watts of wasted battery power that is doing nothing but heat things up. Oh the humanity!

Devo7_Vreg1_800.jpg


For little effort it is possible to substantially improve the battery run time. All that is needed is to remove the stock 5V VReg and replace it with a DC-DC step down switching regulator. Sounds like a lot of trouble? Not really, it took me less than an hour to do it.

So get on eBay and purchase a VReg like this one (it's not the same one I used so it's wiring will be a different):

Devo7_Vreg4.jpg

Cost is about $2. You can find it by searching for: Mini Adjustable Step down Power Supply Module DC-DC Converter


Remove the old 7805 VReg, like this:

Devo7_Vreg2_800.jpg

 

In it's place install the new Vreg like this (Note: Exact wiring depends on the module you purchased) :

Devo7_Vreg3_800.jpg


IMPORTANT: Adjust the voltage regulator to 5.0VDC BEFORE you solder it in your Devo 7. If you skip this important step then you will create an expensive paper weight (translation for non-native english readers: You will destroy your Devo 7 and cry yourself to sleep).

With the new Vreg the current draw is a lot less. That means MUCH longer Devo 7 run time. Here's the new current measurements (with back light on):
12V Current (fresh Alkaline battery): 80mA
9V Current (exhausted battery): 120mA

For only $2 the Devo 7's 220mA current draw was reduced to 100mA average. That's a 2X improvement. Twice the run time for little cost. I like that.

 

 

Edited by Mr.RC-Cam
Info on NiMH charging.
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On 6/28/2016 at 9:45 PM, Mr.RC-Cam said:

I'm not a big fan of the Rodeo FPV camera's soft focus and color rendering. But I like its FOV (field of view) which is spec'd as 110 degrees. It does well in low light conditions too. BTW, it is a PAL camera, not NTSC.

For my first attempt at achieving better FPV video quality I installed a different micro camera. I purchased the NTSC 600TVL micro camera from BangGood but it is available from a long list of China based sellers and eBay.

CMOS-600TVL1.jpg

 

This camera is advertised by every seller as 600TVL. But I've heard that it is officially a 420TVL. Also, many suppliers claim it has a 110 or 120 degree lens. But the real FOV is about 170 degrees, which is much wider than I normally prefer for FPV.

For lowest weight I removed the existing wires and its integrated microphone. A short 35AWG cable was created that has a 3-Pin 1.25mm micro connector that is identical to the existing camera's connector (got it on eBay). Now I can simply disconnect the stock camera and plug the new camera in. Final weight was exactly the same as the original camera (2.5g).

I wanted the new camera to mount exactly the same as the original. A custom designed 3D printed mounting bracket with pivot axle took care of this.

cmos_cam2_1000.jpg

cmos_cam3_1000.jpg

 

The new camera goes in the Walkera Rodeo just like the original. The articulation feature works the same too. Camera transplant is a success!

cmos_cam1_1000.jpg

 

This camera has an adjustable focus (something Walkera did not permit on their camera) . I tweaked it for best far field image quality. Here's a video of the camera's maiden test flight.

My HMDVR recorder substantially reduces the image quality so keep in mind that my live video looks much better.

I have mixed feelings about this camera mod. I like its improved focus and better colors. But I'm not enjoying the über wide FOV. Unfortunately I cannot find a source for a compatible IR blocked 2.1mm lens, which is what I'd like to use instead. Maybe the final decision will involve a coin toss.

 

Hi, can u post the stl for the cam mount ??

Thanks G

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Quote

can u post the stl for the cam mount ??

No problem, I added the STL file to the posted information.

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The stock camera I received is glued together. Despite my strong-arm attempts, the plastic case would not come apart and the lens refuses to turn. If I use more force something will break. This issue is one of the reasons I installed a totally different camera.

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I tried using a knife to break the bond. Plus I twisted with pliers. My stock lens did not move. I stopped short of crushing the lens body.

I think you will find that no two Chinese products are built the same. On the consumer side, quality control and build consistency is generally considered a myth there.

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On the flip side, it's difficult to find westerners that will work long days for Chinese worker wages ($300 US / month). So I suppose we deserve what we pay for!

Rodeo 150 Altitude sensor hack update:
The MS5611 sensor seems to have gotten lost in the mail. But I received the BMP280 pressure sensor. Unfortunately I didn't have a small enough 3.3V vReg board for the installation in the Rodeo. So now I have to wait for that to arrive. Good thing I'm not in a hurry.

 

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Hey sorry to ask, but do you know how to get the profiles to work with the Tx, as in being able to switch between them with the Tx ?

Thanks G

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