[FW] Tracked 4WD Lifter: Aegis

[overkill]

That sounds like a good compromise - altering the limit switches would be a major PITA.

[R9000]

Thanks so much for all your advice by the way, I have a feeling it'll really pay off having asked these questions down the line. I really appreciate your patience answering my noob questions. :P

[overkill]

I have an ulterior motive - having just ordered almost the same linac as you, I get to see how your design pans out before I have to get mine built . I'm also interested to see how your tracks work out.

[R9000]

Me too.

[R9000]

Alrighty, so I got around to starting on my electronics today (waiting for armour and other bits to arrive before I can start on the body). One thing I've learned is that EC3 connectors are the bane of my existence, it took me a good two hours to figure them out and get a few of them soldered. Before I start modifying TZ85s into brushed variants, I decided to test my third TZ85 (which will stay brushless) with my Turnigy Helidrive SK3 Motor. It works great on the throttle slot. However, it only spins one way. I've tried connecting it to other receiver slots, and the receiver refuses to start and just beeps if I don't hold the stick down at 0.
So this is a problem: I need to get my motor to be stationary when the stick is in the middle, turn one way when it's at the bottom, and the other when it's at the top. I think this is an ESC issue, having poked around on various RC forums to try and get the transmitter to tell the receiver to run backwards. Now I'm sure it'll be fine on the brushed modified TZ85s given that they've been set up especially for this situation, but what do I do with this one? Do I look for some other brushless ESC whose zero point is at 50% throttle? Or is there some way to modify a brushless TZ85 to run forwards and backwards?

Anyway, here's a quick vid of me testing the SK3, sadly with no sound because I forgot to unmute my mic. :/ Next time I'll remember. :P

[R9000]

Ok, some research later, it would appear that TZ85s are unidirectional ESCs. I didn't realize some ESCs were only one-way. Obviously they have been made reversible by the BotBitz hack, but that's for brushed motors. Does anyone know how to program them to be reversible, or could you suggest an appropriate reversible brushless ESC for the motor if this isn't possible? Would something like this be appropriate?: http://www.ebay.co.uk/itm/EZRUN-120A...IAAOSwwPhWil9e

[overkill]

You can get a new firmware for the TZ85a that makes it reversible with a brushless motor. Search for 'SimonK tz85a reverse' but be careful, there several versions with different functions.

[R9000]

Ah yeah, thanks! I've found a big zip file with hex files for loads of different ESCs. Looking at the list though (cross-referencing with the github page), there doesn't seem to be one for the TZ85. Although, there are a few videos of people who have done it.

-Edit- Never mind! According to shakrenaaj (Shakey, I think)'s youtube, it's the BlueSeries version I need.

-Edit 2- Yep! It works! So for anyone who comes across this thread later, here's how you change a brushless TZ85A ESC from unidirectional to bi-directional (reversible), so you don't have to wade through the internet maze I did:

-Get the KKMulticopter Flash Tool from here.
You can use some other flashing tool if you want, like Atmel Studio, but I found this easier.

-Open up your TZ85 to reveal the board inside (you may need to 'convert' some of the 2mm-headed hex screws like I did with a junior hacksaw. Two of them went bald on top straight away, so I had to make a groove in which I could use my small flat-bladed screwdriver.

-Make sure you have the USBasp programming device, and either solder on programming wires (as in the brushed hack post) or use a socket flashing tool like I did. Also make sure you have your USBasp drivers installed (you may need to turn off driver signature verification on Windows).

-Download the SimonK hex files from here. For the TZ85, you'll be wanting the 'bs.hex' (BlueSeries) hex file. Just put it somewhere where you can get to it in a second. There's more information about the hex files in the README file in that Github directory.

-Open up your KKMulticopter Flash Tool (use the 64-bit or 32-bit exe, whichever's appropriate for your system). Make sure the options are set as in the image below. Basically though, just make sure the USBasp device is selected (make sure you've got it plugged in too) and click on the 'File' tab as seen below. You'll need to click the floppy disk button to browse for your bs.hex file now.

-Now just hold your flashing tool (if you're using it) onto the ESC's chip with the red dot on the tool aligned with the small dot on the chip, and click the green flash button. Provided you've got the drivers installed and everything's done right, the software should print out that it flashed successfully. Then just reassemble your ESC, and you're ready to go! Once you hook your receiver, motor and battery back up, the motor should run forwards or backwards, depending on which way you push the stick.



Thanks again for your help, overkill. This weapon is gonna be good.

[cnc_machinist_andy]

excellent info on here for the hack on the tz85's
will that bs.hex also work for the hack to brushed ?

[R9000]

excellent info on here for the hack on the tz85's
will that bs.hex also work for the hack to brushed ?

I'm pretty sure it won't, but all you need to do to hack for brushed is follow this same method with the hex file from the brushed hack post I linked up there. You'll probably want to check out the videos on that post too, as they show a similar process. But yeah, if you follow these instructions but with the hex file from there, you should get forwards and reverse brushed ESCs. I'll be doing it today.