Hi all I have built myself a trailer tug to move my trailer about. I have adapted two trailer movers and have rewired it to a single control box. It works fine but as it is uses relays to control the motors its a pretty sudden start/stop, I would like soft starts so I am looking at building a high powered h bridge designed by Ian Johnstone, my motors are 12v 500w so 42amps so this should be fine.
I tried sourcing the components from the local electronic shop and while the appeared to be keen on arduino there were too many components they could not supply so I have ordered them all through aliexpress now I just have to wait 2-4 weeks for them to arrive.
I was thinking of using a bluetooth module and hopefully be able to use a smart phone to control. I have seen a youtube of a little two wheeled robot controlled by smart phone, adapting that sketch to suit Ian's board will probably be my biggest challenge.
Initially I will build the h bridge on a 7x9 2 layer prototype board but if it goes well would like to use the pcb that Ian has done, however, He has used Eagle .BRD and the PCB printers want a gerber file. I could redo the circuit in fritzing or is there an easy way to convert a .BRD to a gerber? I tried doing a DFX to gerber conversion but all the layers became one and somehow the curcuit became the size of a kitchen table.
Any thoughts or advice would be greatly appreciated
thanks
Eagle can export Gerbers. It's one of the main functions of Eagle. It's called "CAM Processor" in the File menu. Usually you end up with many separate files representing the top and bottom of the board for the copper, solder mask and silkscreen, so then you have to be careful to keep the set together at all times.
Thanks, will give it a go
and it worked, thanks boards are on the way
Any thoughts or advice would be greatly appreciated
Two things I noted on the site, 1) there appears to be no schematic of the H-bridge circuit, and 2) no mention of weather the H-bridge actually worked as desired. DIY H-bridges generally don't work well if at all. You might consider purchasing an H-bridge instead of DIY.
http://www.ebay.com/itm/Semiconductor-BTS7960B-43A-Stepper-Motor-Driver-H-Bridge-Drive-For-Arduino-YUUS-/161352840359?pt=LH_DefaultDomain_0&hash=item259160f4a7
Hi I think it works since he has gone from prototype board to a pcb, we will see. Do you know where I could purchase an H bride capable of 12v@50amps? I couldnt find any
Another possibility. You might want to check the driver chip data sheets to see what the running current and peak current values are. lots of motor drivers on ebay. Worse case you may be able to parallel MOSFET based H-bridges to meet the desired running current values.
http://www.ebay.com/itm/Dual-BTS7970B-BTN7970B-70A-DC-Motor-Driver-Drive-Module-H-Bridge-PWM-Control-/321204989173?pt=LH_DefaultDomain_0&hash=item4ac94f2cf5
thanks will give one of those a try