sx8851sv

In the other thread, use SMC3 sketch and wiring, setting MODE2 (instead of MODE1), and all should be good for you.

Hey, I just found your thread and as I'm totally newbie in this, I wonder how this work in comparison with sabertooth.. Things I understand are that BTS7960B can replace sabertooth but need 1 for each motor. Arduino can drive them directly from code instead of sabertooth that need input potentiometer to drive the motors through arduino and sabertooth. Is that really how this work?

kirt, will answer this better..but im pretty sure they both need a potentiometer for position feedback. The sabertooth is an independent closed loop controller which essentially turns your motor into a servo..you can even use servo sketches to drive them. I'm working with a BTS right now. It works with downloadable software that you get for free on here called simtools. When using both you have the capabilities of a sabertooth at 1/10 the cost

If you are using 12V motors, I'd recommend the JRKs. They are very common here, very easy to use, and pretty resilient. They attach directly to your computer via USB, no Arduino needed.

What follows is all regarding 24V... Disregard if you are able to use 12V motors.

I have a Sabertooth and Kangaroo. While I don't mind the Sabertooth, the Kangaroo has been a bit of a let down. That said, the coolest feature of the Sabertooth was it's ability to use the Kangaroo, so for all my projects I've been switching over to the IBT-2 boards. They are amazingly cheap, very reliable, and pretty easy to use. In addition, if you roast one, you only need to replace the single unit, so I have a number of spares w/o breaking the bank.

If you are new to electronics, I'd probably stick to the monster motos. They are VERY popular, and once you find some working boards, very reliable. Because they are so popular, you can't swing a cat without hitting source code and wiring diagrams for them. They have had a recent string of bad units showing up, but I'm certain that'll be resolved soon.

In fact, as a developer, I'm not afraid of code and electronics. If I well understand, BTS7960B can easily replace sabertooth and motomonster, but we've to handle motor drivers in the arduino code with data send via simtools.
I'll use this with 24V motors as I want quite powerfull sim.
Also, I must use potentiometer on motor to know motor position angle.

Does these BTS7960B handle quick switch of power so we can turn clock or anti clock wise the motors without breaking the board?

I keep reading comments about faulty monster moto boards.

No one makes it clear though that it is about cheapo knockoffs and not the original board by sparkfun.(I don't relate to the company... I use pololu dual vnh5019 board on my project for its 24v capability).

This is not a personal attack against the participants of this thread.(or any other).

I just want to say that:
1)it is very unfair for a company that makes quality products
2)it is very misleading information
3)it's one more case that prooves that you get what you pay for.

Pretty much any controller you buy will have some sort of protection against the back EMF you're speaking about as a result of quick direction changes, but your power supply may trip. Im using server PSUs I wired together, and they go into some sort of limited op mode if this occurs. Unfortunately the only suggestions I've gotten to fix this suggest using car batteries wired in parallel to absorb the current spikes. Which in my case would include 4 12v batteries scattered around my unit. Not very cool looking. Or you can use a large capacitor and a diode, but I've heard of this having some issues as well. I'm waiting for one of the really intelligent guys on here to develop and sell a quick easy non-dyi fix to this issue, I'm sure it's right around the corner

@kimballfount I too had this issue until I dropped my KP in SMC3 (which I believe you are also using?). I went from three server PSUs wired together for three motors to one PSU running all three without issue.

Hey kirk, as you've been the most valuable resource in troubleshooting I've got another one for you...

Issue: When I start the arduino it starts rotating continuously to the left. The only way to stop it is to loosen the pot and manually feed it into the direction of travel. It's been mentioned that it sounds like my middle analog isnt wired correctly, but Its pretty straight forward (middle wire goes to A0). Its also been mentioned I should switch the wiring of the ground and positive lead on the potentiometer. This doesn't do anything. It does the same exact thing....I'm still using the SMC3 sketch and wire up. Is there a way to tell the arduino, that the position the shaft is in upon starting is the starting point? It seems like it might be hunting around for a place to start. Would getting a continuous rotation pot solve this issue?

I'm assuming you're not using a hall effect pot. Just in case, never ever reverse the +/- pins on a hall effect pot, as they are actually electric circuits and might not survive.

If you have access to a meter, measure the resistance of your pot (across the + / - leads) to get the full resistance, then turn your pot to the half way position, and confirm the resistance is similar between 1 /2 and 2 / 3, and then connect the pot to your device.

You'll then want to adjust the CutoffLimit and InputClip min/max values (per motor). I believe these can be done from the UI. They are probably the defaults, which would explain the behavior you are seeing.

Without gearing, the actual range is going to be pretty small (despite 10 bits input precision, because the range of movement is such a small range of the total resistance), but it'll work fine. However, if you have a multi-turn pot, you almost certainly will need some form of gearing.

Just getting back to initial discussion, I head that these BTS7960B you previously mentioned were quite nice but unfortunately quite slow on direction changes.
I did not yet tried this controllers, nor the Sabertooth one or Kangaroo one, but with your experience, can you confirm the gap between these three motor drivers (complexity appart)?

The Kangaroo is not a motor driver. It is an intelligent controller meant to be paired with a motor driver made by Dimension Engineering, eg. the Sabertooth.
While it does have minor performance issues, the biggest problem with it is the suitability to task. It's a PITA to actually use in a sim.

OK, on the drivers, they are all more than fast enough. 99% of any lag is caused by insufficient power for a given load, and can frequently be compensated for by ensuring your pivot is in the right spot, adding a spring, or reducing the lever size. The remaining 1% is user error, because USB is pretty fast.

How much power you are willing to hurl at your motors? It's all about Watts vs Newtons per Meter.
If you have less wattage, reduce the size of your lever, or use motors with higher gear ratio. Speed and latency are far more important distance traveled.

Most H-Bridges are able to completely switch directions, at FULL LOAD, many thousands of times per second, and subtle transitions at nearly a MILLION times per second. Any performance problems you witness are not the H-Bridge itself, but rather how it's being used.

(edit) I just wanted to distinguish between H-Bridges (cheap, but require a controller such as an Arduino) and true intelligent controllers such as the JRK or Sabertooth (well, it's halfway there... Technically, you can control it using a USB to TTL converter).

Well, what you say is pretty confortant.
I have to admit that such a project need really a lot of tweak and preparation. Yet I've nothing to tell you about how my sim will work, how long will the levers be, ... etc.
I also have to admit that your comment gave me the wish to build my sim using BTS7960B's, the only point that I need to consider is to use more arduino as I initially tought. But with small arduino micro chips, it's not the price that will be a problem.

Actually I'm thinking about building 3DOF sim with surge using 24V wipers (+ G-seat later on a driven with a specific arduino).
Do you suggest using one arduino per H-Bridge and per motor (also coupled with one power supply)?

One Arduino could probably handle 4 motors (ie. 4 of the IBT-2 boards, each board contains 2 BTS7960B chips, forming an H-Bridge). They are fun boards.

An alternative are "Monster Moto" boards, each handles two motors. You'll do fine going either route.

I can't stress enough to pay close attention to how you power everything and how you handle the sensors (pots). Most everything else is pretty free-form, but getting the power supply wrong or the pots wrong can lead to a lot of difficult headaches. I really recommend tackling those issues before building a frame.

Also note: If you are using wiper motors, you must isolate the grounds. There are many threads on exactly how to do this, it looks to be pretty straight forward.

Once you have selected the motors, you should be able to determine their power, and combined with the weight of your sim and yourself, you can pretty easily guess the length of the levers. Later on, you can upgrade the motors pretty cheaply at auction. I like the 4 pole wheelchair motors, and a number of people here use wench motors for that Ultimate in movement.

I blew another BTS7960 today. It got really hot, and it started to make my power supply fan to speed up to a frightening speed. I lowered all of my figures to those recommended at start up in the Utilities Program. Pretty vague description I know, but can someone spitball some ideas of what going on. This time I was running my 12v 20a motor at a high load. Dedas is this what your hbridge did when it blew? Where did you find the new chip?

Moved your question to your own thread. Please do not ask questions about your rig in other peoples threads. It clutters theirs up and side tracks them.