How-To: GT2B --> Badwolf v2

Lightweight / Folding / Portable EVs - seats optional
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sl33py   10 kW

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How-To: GT2B --> Badwolf v2

Post by sl33py » Aug 16 2015 2:35am

Credit to Badwolf and others who have obviously developed and done this before.

Besides Badwolf's directions on thingverse, and some detail from others here on how they did theirs - there wasn't anything consolidated in one spot. I'm a visual person and since couldn't find a step-by-step, i figured i'd build one while doing mine. Hopefully to help out the next person who wants to do this, and give back to the ES community that's helped me so much!

I had some spare time today and figured i'd give it a shot. Others might have more elegant or better steps, but these worked for me. This does involve your ability to solder and handle delicate electronics safely. If you really have no idea how to do this, i might suggest you get someone to help you.

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I have my HK GT2B, and the 3dhub printed Badwolf v2 enclosure (bit rough print quality, but not horrible):

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There are 8 screws on the side (and under replaceable "backstrap" replaceable grip. Cut or remove the top sticker behind antenna to split it in half).

Take your time. There are a couple other screws on the CH3 mid grip, and 3 more on the steering servo/wheel control. The antenna is super simple and just sticks up into the rubber ducky on top of the controller.

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Top
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Bottom
Once everything is pulled out you should have this.

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Pop the labeled cover off, and disconnect the Steering channel.

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Looking at alignment and test fitting to v2 enclosure.

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Top and Bottom of left side to remove.

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slow and steady w/ a dremel cutting disk

Let me just say that i SUCK at desoldering... couldn't find my solder wick and finally resorted to slightly more "brute force" methods.
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On each side of the USB Mini-B charging port there is this solder you need to remove. Desolder or...

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I quickly grinded it off with the dremel cutting disk and then used my razor knife to "lift" it while heating the top and bottom solder/pins.
Time consuming and a PITA. If you have good solder wick i think you'd have this done in just a few minutes. I went slow and fiddled with it for entirely too long, but got it done eventually.

Battery steps:
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Pry/peel off the plastic and cover around the battery. I immediately made sure to label + and - , just to be extra sure i dont mix them up.

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Test fit in other half of enclosure.

Waste not want not
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Donor wires for both the battery and relocating the USB charging port (don't throw these away).

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A bead of solder on the + and - terminals on the battery, notice i kept the connector for the battery to connect to the PCB. Instead of hard wiring/soldering it later i could replace it easily.

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Some electrical tape around the perimeter then gorilla taped it up.

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a simple loop of the antenna and electrical tape to hold it in place at the bottom.

I was going to run to the hardware store for the extra m3 screws i needed, then remembered i had this "standoff kit" from Amazon for a quadcopter KK board - perfect!
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Getting close to completed. I'm not sure if it was just my print, or if all of them are going to be like this, but i found the range too restricted for full throttle to full brake on my enclosure.
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I got it pretty well lined up. Notice the almost flat bar extending out from the trigger pivot. I marked it w/ a sharpie to cut and tried to keep it snug for good stability (going to be pulling/pushing on it). I also notched out the part that slides down onto the m3 bolt so it went around both the bind and one of the adjustments (throttle iirc).

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Bent the backside of the throttle/trigger board to sit flat (but contact the enclosure for more support).

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You can see how much i cut away to give full throttle range.

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re-using the wires from the handle, the 3 wires to the USB Mini B charging port

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A bit of a closeup of the battery and charging ports. Note that the USB charging port does use all 3 wires, but since i had to mangle it a bit when desoldering the port, i put the white wire in the middle to the bottom side (more room to work at the time as well). So top has black and red, with the middle white connected on the bottom. You can also see the notched out part of the throttle assembly to clear the bind button and throttle adjustment. To keep it straight (what does what), i used the label from under the top cover to help keep them ID'd.

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Pretty much ready to screw it together and test. Note - use the shorter screws to hold the halves together. The longer ones i tried on the two bottom broke off part of the screw hole they went into. I used the shorter screws on the top 2, then used the longer ones on the two bottom holes. If you brake off the screw hole bottom piece - just re-use the longer screws. I've had it apart a few times already and seems to be holding up ok w/ me being careful not to try to tighten it down too much. Could be typical, or just the lower quality print (medium quality on 3dhub)...

Moment of truth:
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plugged in and charging! I then got it to bind up and control my board w/o any trouble.

Some issues i had:
- On/Off extension did not line up for me. So i have to use a straw/keys/long-pokey-thing to turn it on.
(FIXED! - I drilled a small hole in the on/off switch and screwed in a small button head screw which gives me a flush switch on case - image below)
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- Broke the bottom 2 screw holes w/ longer screws from too much force/too thin or poor quality print, or gunk in the screw hole splitting it?
- I'm an idiot. I wanted to dye the plain white PLA printed enclosure. Directions on the RIT dye say to use boiling water. Don't do that. One of the two enclosures is permanently warped. Hot tap water actually did great cleaning up the adhesive residue w/ some soap before mounting the electronics into it. seemed to also make the enclosure less "flexy" and more rigid w/o warping it. I think my hot water heater is set around 125*.
- 680 Ohm resistors - not currently used. Seems to work fine, but wanted to try it both ways. (anyone with specifics on why you need them please chime in!)

I have 100 of the 680 Ohm resistors. If anyone needs a pair for their new enclosure, just PM me. I'll ask you to send a stamped envelope so i can drop them back in the mail to you.

Bench testing this worked fine. Will try to get it out and ride it soon. Great conversion on the GT2B - now fits in my pocket!!

I hope this helps the next person trying to do this, and let me know if you have questions.

-Rob
Last edited by sl33py on Aug 30 2015 12:48am, edited 2 times in total.

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Re: How-To: GT2B --> Badwolf v2

Post by okp » Aug 16 2015 2:44am

Great Rod !!!! Thanks for sharing

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Re: How-To: GT2B --> Badwolf v2

Post by Freshair » Aug 16 2015 3:02am

Great write up!
sl33py wrote: Note that the USB charging port does use all 3 wires, but since i had to mangle it a bit when desoldering the port, i put the white wire in the middle to the bottom side (more room to work at the time as well). So top has black and red, with the middle white connected on the bottom.
What is the purpose of the white wire? Did not see it being used in badwolfs instructions and did not put it in, have tested the charging and everything works without it.


As for the resistors this is what badwolf told me in regards to using them, "with the transmitters I've used they all need some sort of input on it to start up". They being the inputs no longer being used.
Low impact to no impact

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Re: How-To: GT2B --> Badwolf v2

Post by Poweralti » Aug 16 2015 3:03am

You aré the talent

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Re: How-To: GT2B --> Badwolf v2

Post by sl33py » Aug 16 2015 3:22am

Pocketable!
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Re: How-To: GT2B --> Badwolf v2

Post by BadWolf » Aug 16 2015 8:04am

Great tutorial! Will link to this thread on the thingiverse page.

Strange that the extension for the powerswitch didn't line up for you.. I guess you also tried rotating it 180 to make sure it was inserted the right way?

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Re: How-To: GT2B --> Badwolf v2

Post by sl33py » Aug 16 2015 11:56am

BadWolf wrote:Great tutorial! Will link to this thread on the thingiverse page.

Strange that the extension for the powerswitch didn't line up for you.. I guess you also tried rotating it 180 to make sure it was inserted the right way?
Thank YOU for figuring this out and making it possible to shrink a great Tx to a pocketable size!!

I tried rotating it, but no luck. My switch lines up with the slot, so the offset made it need to be angled which didn't work. Also, if I fully seated the extension, it wasn't long enough to clear the top of the case. Not sure if I had the PCB too low in the case bottom? I only used the single standoff.

Either way, some keys or anything like a straw or bind pin work. I might try to relocate the on/off switch like in your v1 if it bugs me too much.

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Re: How-To: GT2B --> Badwolf v2

Post by sl33py » Aug 16 2015 12:01pm

Freshair wrote:Great write up!
sl33py wrote: Note that the USB charging port does use all 3 wires, but since i had to mangle it a bit when desoldering the port, i put the white wire in the middle to the bottom side (more room to work at the time as well). So top has black and red, with the middle white connected on the bottom.
What is the purpose of the white wire? Did not see it being used in badwolfs instructions and did not put it in, have tested the charging and everything works without it.


As for the resistors this is what badwolf told me in regards to using them, "with the transmitters I've used they all need some sort of input on it to start up". They being the inputs no longer being used.
I wasn't sure how the USB charging port connected, so when I saw all 3, including white, on his v1... I figured it might be needed.
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I plan on adding the resistors since I have them. Fiddly little buggers to squeeze in there!

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Re: How-To: GT2B --> Badwolf v2

Post by cmatson » Aug 16 2015 6:45pm

Thanks man!

This is SUPER helpful!

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Re: How-To: GT2B --> Badwolf v2

Post by killisch » Aug 16 2015 10:31pm

Awesome work.

Would anyone happen to know the resistance range of the trigger potentiometer?
That's assuming it is in fact a pot.

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Re: How-To: GT2B --> Badwolf v2

Post by lox897 » Aug 17 2015 1:21am

Thanks Sl33py I have been waiting for this. I am not going to use the resistors unless I absolutely have to. I have taken everything out and am pretty much done. BUT... the antenna fell off. Is there anyone who might know if this is fixable? Do you know how to?

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Re: How-To: GT2B --> Badwolf v2

Post by mccloed » Aug 17 2015 9:53am

sl33py wrote:
BadWolf wrote:Great tutorial! Will link to this thread on the thingiverse page.

Strange that the extension for the powerswitch didn't line up for you.. I guess you also tried rotating it 180 to make sure it was inserted the right way?
Thank YOU for figuring this out and making it possible to shrink a great Tx to a pocketable size!!

I tried rotating it, but no luck. My switch lines up with the slot, so the offset made it need to be angled which didn't work. Also, if I fully seated the extension, it wasn't long enough to clear the top of the case. Not sure if I had the PCB too low in the case bottom? I only used the single standoff.

Either way, some keys or anything like a straw or bind pin work. I might try to relocate the on/off switch like in your v1 if it bugs me too much.
Ha! I ended up using keys on my V1. Was too lazy to solder in a power switch. It also works as a security measure. :lol:

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Re: How-To: GT2B --> Badwolf v2

Post by sl33py » Aug 17 2015 12:14pm

lox897 wrote:Thanks Sl33py I have been waiting for this. I am not going to use the resistors unless I absolutely have to. I have taken everything out and am pretty much done. BUT... the antenna fell off. Is there anyone who might know if this is fixable? Do you know how to?
It should be repairable. Take a pic good pic of it so we can see what broke and walk you through repair. You might also try with the antenna broken off. Realize that the antenna gives you range, which standing on the top of the Rx might not be needed. I'd still repair it if i could.

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Re: How-To: GT2B --> Badwolf v2

Post by cdn » Aug 17 2015 1:44pm

Great write up. Now can proceed to do the same. Only thing missing is to print the enclosure. Where did you get it printed? Hopefully some place local because I'm in Renton.

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Re: How-To: GT2B --> Badwolf v2

Post by lox897 » Aug 17 2015 5:38pm

sl33py wrote:
lox897 wrote:Thanks Sl33py I have been waiting for this. I am not going to use the resistors unless I absolutely have to. I have taken everything out and am pretty much done. BUT... the antenna fell off. Is there anyone who might know if this is fixable? Do you know how to?
It should be repairable. Take a pic good pic of it so we can see what broke and walk you through repair. You might also try with the antenna broken off. Realize that the antenna gives you range, which standing on the top of the Rx might not be needed. I'd still repair it if i could.
I think I will just try and heat the solder up and put it back in.
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Re: How-To: GT2B --> Badwolf v2

Post by sl33py » Aug 17 2015 11:36pm

cdn wrote:Great write up. Now can proceed to do the same. Only thing missing is to print the enclosure. Where did you get it printed? Hopefully some place local because I'm in Renton.
I don't have a 3D printer, so i've used 3dhubs.com and shapeways. 3d hub is much cheaper, but print quality on "medium" is pretty rough. I don't mind terribly, but might look for a better/higher-quality print next time.

Shapeways cost is about $36.
3Dhubs is about $15 in comparison.

D/L the stl files and play with print options.

HTH - GL!

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Re: How-To: GT2B --> Badwolf v2

Post by sl33py » Aug 17 2015 11:39pm

lox897 wrote: I think I will just try and heat the solder up and put it back in.
Definitely repairable. To strip that wire, i usually burn the end and pinch off the plastic sheath. Then tin the wire and heat/sink it into the other solder. Easy.

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Re: How-To: GT2B --> Badwolf v2

Post by l3thaltank » Aug 20 2015 2:21pm

What pins are the 680 ohm resistors soldered to? The steering channel output but how so? Does anyone have a picture?

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Re: How-To: GT2B --> Badwolf v2

Post by vince086 » Aug 20 2015 3:58pm

l3thaltank wrote:What pins are the 680 ohm resistors soldered to? The steering channel output but how so? Does anyone have a picture?
Between the center pin and the two outer pins.
Center one is signal pin, for the outside ones, one is V+ (pobably 5v) and the other ground.
So both resistor attach to the center pin and one each to the outside pins.

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Re: How-To: GT2B --> Badwolf v2

Post by l3thaltank » Aug 20 2015 4:03pm

vince086 wrote:
l3thaltank wrote:What pins are the 680 ohm resistors soldered to? The steering channel output but how so? Does anyone have a picture?
Between the center pin and the two outer pins.
Center one is signal pin, for the outside ones, one is V+ (pobably 5v) and the other ground.
So both resistor attach to the center pin and one each to the outside pins.
Thanks Vince that was very helpful!

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Re: How-To: GT2B --> Badwolf v2

Post by jamesonotc » Aug 20 2015 9:05pm

cdn wrote:Great write up. Now can proceed to do the same. Only thing missing is to print the enclosure. Where did you get it printed? Hopefully some place local because I'm in Renton.
Good to see you another local,I too am in Renton

I'm currently building a board and will be using a case I got from sl33py for my gt2b swap, lets link up sometime!

how far are you along with your project on the other portion of your build?

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Re: How-To: GT2B --> Badwolf v2

Post by jamesonotc » Aug 20 2015 9:23pm

Sl33py good work! I will use this as a reference for when I attempt my swap over. Thanks for all the efforts man!
jamesonotc wrote:
cdn wrote:Great write up. Now can proceed to do the same. Only thing missing is to print the enclosure. Where did you get it printed? Hopefully some place local because I'm in Renton.
Good to see you another local,I too am in Renton

I'm currently building a board and will be using a case I got from sl33py for my gt2b swap, lets link up sometime!

how far are you along with your project on the other portion of your build?

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Re: How-To: GT2B --> Badwolf v2

Post by cdn » Aug 21 2015 10:01am

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Just got finished the swap. Once again sl33py's write up with pix was invaluable.

The hardest part of the swap was the unsoldering of the usb port and the correct placement positioning of the trigger assembly. I think the most time was spent making the trigger assembly fit properly without having to modify the case.
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Re: How-To: GT2B --> Badwolf v2

Post by cdn » Aug 21 2015 10:18am

jamesonotc wrote:
cdn wrote:Great write up. Now can proceed to do the same. Only thing missing is to print the enclosure. Where did you get it printed? Hopefully some place local because I'm in Renton.
Good to see you another local,I too am in Renton

I'm currently building a board and will be using a case I got from sl33py for my gt2b swap, lets link up sometime!

how far are you along with your project on the other portion of your build?
Sounds like a plan. I'm pretty close to final assembly. This build is a revamp of an existing running board. Just waiting for bearings.
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Re: How-To: GT2B --> Badwolf v2

Post by sl33py » Aug 21 2015 12:21pm

cdn wrote:
GEDC0040 (640x428).jpg
GEDC0046 (428x640).jpg
Just got finished the swap. Once again sl33py's write up with pix was invaluable.

The hardest part of the swap was the unsoldering of the usb port and the correct placement positioning of the trigger assembly. I think the most time was spent making the trigger assembly fit properly without having to modify the case.
Nice work cdn! I am working on v2 next w/ my other GT2B's. I was going to do what you did w/ the resistors on the next one - use the wires on the steering wheel connector/plug to solder the resistors to. I'll try to take a pic or two when i do this w/ the next one.

Yeah, desoldering the USB charging port is a PITA. I still haven't found my desolder wick, so i will either grab some at Fry's or just do what i did with the first one again (grind off the sides and lever it off w/ heat).

So you have full range on the trigger w/o removing any of the plastic like i did? I'm just wondering if the opening is too small, or if my first print was low quality and not 100% correct dimensions for that opening. I broke down and ordered the 2 sets from Shapeways (spendy), because i want to compare quality w/ the first one. Also ships right to my door vs trying to coordinate w/ someone on 3dhubs. $5 shipping well spent.

Where did you get your print specifically - looks good! If 3dhubs i'll try to use that location!

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