Tronic's DIY dual Mosfet H-bridge (DSMhb)

Can you post photos of your motors? Are they car wiper motors?

You can try using smaller DC motors (from toys) if you like but then you have to use lower motor supply voltage too (most toy motors are 6volts). This will verify that there isn't something wrong with your h-bridge.

Thanos

Thanks for the reply... I haven't taken pictures of my motors yet but I have tried your suggestion with different small motors, and lower voltage supplies.. Still appears to have the same results..

I have tried to change my 74HC chip as that was an easy test... no joy... It is weird that without a motor connected the status led's display properly and when I change direction they respond quickly and bright... But when I connect a motor it is kinda like the fet's aren't turning on properly for some reason...

It's a soldering mistake most likely. Recheck all solder spots, and have a look on the leads, perhaps there is a shortcut somewhere.
Or the RX TX wires are wired crossed.

Dont forget to isolate the GND from motor housing.

regards

I will triple check this again however I did go over everything with a multimeter and magnifing glass... thanks for posting back... So there would be no issues with the amount of power output by my arduino PWM pins? I believe it is only capable of 250ma..

Why I have suspicion that you use the same power source for motors and for arduino?????? The motors must have their own power source with their grounds isolated from the Adruino ground !!!!!

The Arduino does not drive the mosfets!!! The signals it needs to sent are a few uA only. The driving of the mosfet gates are done from the four transistors placed next to the mosfets!

A photo of your connections would help! A picture is a thousand words!!!



Thanos

I will try and get you some pics... I am definitely using an external power supply for the motors and the grounds are not connected in any way...

Hi Thanos,
any advancements on using the ACS756 Hall Effect Current Sensor as I have just received 6 samples of the ACS756 and the A3941 devices from Allegro, took about 6 weeks to arrive but at least they were free.

Regards Senetor.

does anyone know where to buy the parts for the h-bridge? :

Thanks
stephane

I want to build a h-bridge, could someone please upload a bom import list for mouser.com? :happy:

Hi,
I have built both AMC controller and H bridge. The controller seems to be working perfectly as the LCD does everything it should. It responds to Pots and slider bar of profiler. when I attach the H bridge howver, nothing happens. No lights or motor movement of any kind. My wiper motors are not grounded to frame, and the H bridge/AMC are separated also. I am also confident my wiring is correct from controller to H bridge.

Are there trouble shooting tips anyone can advise me on? Is there an easy way to determine if my Mosfets are OK?
Thanks for any help,
Dave

Hi Dave,

Perhaps you placed in wrong direction the 74HC08 chip, or made wrong connection on the cable that connects the AMC and the DSMhb boards... Also be sure to have installed the mosfets in such way that they facing back to back!!

Some photos from your boards with cabling installed would help to determine the problem.


Here is a simple mosfet tester that you can build on protoboard:
http://www.x-simulator.de/forum/post12552.html#p12552

Regards, Thanos

Hi!...

After the lost of my little and beloved pololu ( : where ever you are, pal), i've nearly finnished the DSMhb... but in all the stores at my place is impossible to find the Mosfets... i just found one that will import them for 9€ each, but i don't want to pay the honolulu holidays to the store man. At least not in crisis times

So... i've seen some german places (on the AMC topic there's a list in german) as cheap as 0'90€ each... how could it be possible? Anyway, i really need some one here to help a little. The stuff i need:
8x - IRF4905 (TO-220) (Better 8 instead of 4 becouse i will blow them for sure... or not, who knows)
8x - IRFZ44 (TO-220) (Same as above :mug1: )
Ah, this is not on this part list, but the Hall sensors are like asking for cold fusion... impossible, impossible. soooo... add:
2x - sensor Hall ss495

If someone knows how to ask them from internet to my place (spain) or to your place and i will pay whatever is needed and a little charge if you need to move to post office... please, you will earn an ilimited bonus freeride on my sim (and a couple of beers between).

Thankyou in advance.
knob2001 (joyrider + AMC + DSMhb + Freetrack)

Hi Oscar,

You can find those parts in ebay in lots in nice value:

10x IRF4905:
http://cgi.ebay.co.uk/10PCS-IRF4905-Tra ... .m63.l1177

10x IRFZ44:
http://cgi.ebay.co.uk/10-pcs-IRFZ44N-IR ... 240%3A1318

And you could even buy the stronger replacements of IRFZ44, the IRF3205:
http://cgi.ebay.co.uk/IRF3205-BY-IR-LOT ... .m63.l1177


As for the ss495, I know, they are amazing devices. Too bad that they are hard to find. I had to order 10 of them to get a better price when I ordered them from my local supplier. Here is a tool I often use to locate on-line sources for parts: http://octopart.com/search?q=ss495

Best Regards, Thanos

@stefkefsx,
I was working on this for myself and have not purchased these yet, so the list may need to be re-checked to confirm accuracy. but here is a BOM for mouser.com. Just cut and paste the list below into the BOM import tool. It does not include the wire. Other than the wire everything else is there. Total cost before shipping is $40.03.
I must say though, that getting the mosfets on ebay, as suggested by TronicGr will save some coin and give extra parts in case you blow one up. Once this BOM is verified it will go in the Wiki, so if you find any mistakes please let me know. thanks.

595-SN74HC08NE4|1
511-STP80PF55|4
844-IRFZ44PBF|4
512-BC546ABU|4
271-3.6K-RC|4
660-MF1/4DCT52R2201F|4
660-MF1/4DCT52R1501F|4
660-MF1/4DCT52R6800F|2
271-160-RC|4
821-1N5819|8
512-1N5245BTR|8
647-UVR1J101MPD1TD|2
433-SP501012H|1
538-39544-3002|4
538-39543-3003|8
649-DILB14P-223TLF|1
538-26-60-4100|1
538-09-50-3101|2
538-08-50-0105|15
859-LTL-4234|2
604-WP7113ID|2

Hi Devin,

The list is ok except of the 12V PC fan, that is too small. I removed it from the list. We need a 80x80mm fan that can be found in any computer shop.

595-SN74HC08NE4|1
511-STP80PF55|4
844-IRFZ44PBF|4
512-BC546ABU|4
271-3.6K-RC|4
660-MF1/4DCT52R2201F|4
660-MF1/4DCT52R1501F|4
660-MF1/4DCT52R6800F|2
271-160-RC|4
821-1N5819|8
512-1N5245BTR|8
647-UVR1J101MPD1TD|2
538-39544-3002|4
538-39543-3003|8
649-DILB14P-223TLF|1
538-26-60-4100|1
538-09-50-3101|2
538-08-50-0105|15
859-LTL-4234|2
604-WP7113ID|2

:thbup:

Regards, Thanos

The modified DSMhb (expresspcb version) is spaced for a 92mm fan.

Hi R-eng,

Yes, I know. The above BOM list is for the PCB plans I gave for PDF layout DSMhb1.2b that has 80mm fan mounting holes...!


Regards, Thanos

@ TronicGr,
thanks. Sorry, I didnt pay attention to the spacing on that fan.

Hi tronic,
do you think this mosfets are better than the IRFZ44?. Do they not burn quickly as the IRFZ44?. The IRFZ44 are a little bit sensitively : .
I ordered some to try them.

Hi Tronicgr,

Any technical reason why on you H-bridge you have 'Motor1 IN1', 'Motor1 IN2' and 'Motor1 PWM Channel' inputs ? Are not IN1 or IN2 always in opposite logic states, except if you use them for break purpose...
I'm just curious :thbup:
Cheers.
OscarH