1/35 M4 Halftrack(s) to RRC Tamiya, Testors

[modler]

It didn't work because the parent project, which has an L298 chip, needs PWM, inA, inB signals for each motor.
I am not particularly strong in electronics, more precisely, it is often difficult to read the datasheet (English is not my native language). I think DRV8833 will not fit, what do you think?
So far, I have only learned how to design boards in EasyEDA, and then with the help of an autorouter.

I ordered these ESCs to control the RC outputs from the board:



https://aliexpress.ru/item/1005003152945927.html

Do you have a pinout for the L298 chip? If I could see that it would become clear as to what you are doing with it.

The ESC you show does not have voltage requirements as part of the data. I need a bit more info to be able to help. Perhaps a block diagram of what you are doing. Hand written is fine and just post a picture of the block diagram.

[modler]

Thank you! I clearly understand--and memory confirms---the "escapement" steering. In the late '70s, Ertl sold two RC toy tractors (JD 4430 and IH 1486) with such steering. It was painful to watch, the all-or-nothing movement causing some tricky handling. RIP escapement steering.

I recommend Modler's explanation, immediately-above, to anyone checking this thread. It's well-done.

RIP escapement steering. Lol yes may they rest in pieces.

As you can see the old M4 Is going to get an update I can no longer stand to looks at it in its present form

This update will reunite the well used frame to the well used body and will re-join the ranks of my favorite models Arizona patina as an extra bonus

I took the old escapement from the M4 and converted it to a Servo steering box. I used a standard UM Servo in this one. Because you have to add linkage to the control horn of the Servo to the steering linkage, it takes way more time than using a screw drive Servo. I was determined to make it work with the standard Servo and spent way too much time getting it just right with plenty of throw as you need good steering movement and lots of it in a half track. Next one I will use a screw drive Servo. Anyway, I cut up the the Testers M2-4 or what ever it is to install the reworked steering box in the Testers model. I bought that model 3 years ago at Drug Mart for $14.0 and finally started the process of making it radio controlled today.

Servo gearbox test video
https://youtu.be/lFbILOotNVA

[Captain Morgan]

The little green printed circuit board I've shown in the picture is a stripped down version I created based on the Open Panzer project by the respected LukeZ.

I made it for myself when I was interested in - and whether it is possible to animate - models for gluing. In my childhood, I dreamed of radio-controlled toys, as in this cartoon:

phpBB [video]

(based on the novel by S. King)

I have not tested everything yet, but today I created a 3D model for printing on a 3D printer, to create a gun recoil module, to implement it into a prefabricated model from ZVEZDA KV-1 1:35 scale:

phpBB [video]

As for the connection of the DRV8833 module, the question of controlling it - the main motion motors:

I changed the author's project - I left it on the board (on the board - these are the conclusions on the right) - the conclusions from the main chip, for connecting L298b analogues, you can see this on the author's diagram:



That is, I brought out all the soldering contacts that should go to the L298 chip.


In practice, I can assemble a separate module based on the L298 - with a separate board, solder wires to it from the main board. But the L298 chip, and diodes for it - have to take up a lot of space inside the model.

But I was hoping to use the DRV8833 as half of the L298. This is where my knowledge is lacking.

[modler]

Captain Morgan

Ok well, I am not clear on what this DRV8833 is driving or controlling. Is this for the recoil motor? As far as PWM input, there is a + and - phase PWM protocol. I ran into that once where the receiver outputs did not seem to work because the Transmitter was the wrong polarity phase (positive phase shift PWM) and the receiver wanted (negative phase shift PWM). So when using PWM, there is a polarity involved and must match between the Transmitted and received PWM. I have a Transmitter that can do both as I use both +\- PWM in my legacy receivers. Of course newer R\C equipment is 2.4G. Anyway, Your project is very interesting but I need more details to be able to help solve the issue.

In standard practice of debugging an electronic design, I use a block diagram with flow chart and Boolean logic truth table of the logic elements in use that explains the principal of operation of the device without specifics of the hardware design. And in this case, mechanical drawings of the device being controlled with electronic interface points outlined would be useful.

This would allow me in an timely manner to diagnose the problem. I wish I could pull a rabbit out of the hat for you with the information you have provided thus far but I need more info to do that.

[modler]

I am still working on this Halftrack. Yesterday I got to drive it a few minutes before the track idler wheels failed. They are weak on this model and need beefed up. Not doing anything too fancy just fixing the problem with basic repair methods

[modler]

overhauling the Track idle wheels made all the difference Now it runs very well and despite my improvised Track roller repair on the right side seems to work very well as a rolling chassis test. Next is to install the body.

Chassis test with MTM gearbox driving the tracks video.

https://www.youtube.com/watch?v=qZNWn3-DFpA

[modler]

Ok I guess people are wondering if I will get this Halftrack going or what well I did finally get it going. It took more time than I would have liked but after driving it around on my workbench track I have to say that is was worth it to finally have a 1/35 Halftrack that is running on its factory tracks and rollers. Even though it is beat up and missing some parts it performs better than any other wheeled military model that I have. My M11 Tank transport Trucks can not make it around the track even with rear 8 wheel drive.

Oh and by the way, this build was only possible thanks to the very small MTM gearbox

Here is a quick video showing some off road capability of the half track
https://www.youtube.com/watch?v=IyauLXvnnKE

This video is a little longer
https://www.youtube.com/watch?v=5irl-t126hs


Slo mo video
https://www.youtube.com/watch?v=qprBPLUgSTY

[Herr Dr. Professor]

Wow: that 's a rugged looking ol' beastie! Do go for the Opel Maultier! Remember, it's only money, and if you think you are getting short on space, remember, I once put 2,000+ 1/16 scale model farm tractors and equipment in a 600 sq. ft. basement of my 11-sided home.

[modler]

Wow: that 's a rugged looking ol' beastie! Do go for the Opel Maultier! Remember, it's only money, and if you think you are getting short on space, remember, I once put 2,000+ 1/16 scale model farm tractors and equipment in a 600 sq. ft. basement of my 11-sided home.

I opened the Opel Halftrack kit and looked it over. It has rubber tires and nice tracks. Same tracks as a Panzer II so aftermarket tracks are available if needed. This looks like a good candidate for RRC conversion. From now on, I will make sure any model I build has after market tracks or I will pass. Unfortunately, The Crusader Tank has no aftermarket tracks that I can find at this point, still looking.

I have a few projects in front of it but it will be on the bench soon.

[modler]

Just recently revised the MTM gearbox mount on this M4 Halftrack. It uses one precise self tapping screw to mount to the frame.

I will post pictures asap. Internet not letting me do it at this moment.

I also ordered some additional motors\metal gearboxes (same type that are in the MTM gearbox assemblies (from France) so that I can swap out the motors for a faster speed output. More speed less torque as the Half Track needs very little torque to move and I will trade the torque for speed with a motor swap.

here is a M4 HT video in the meantime
https://youtu.be/IyauLXvnnKE