sbr523

ok I decided I suck at eagle so I will post what I have and let someone else clean it up for me.



btw anyone that wants to build it here you go

nitrous controller

it is a mess and the schematic needs to be cleaned up and the 2 combined together but it works. if anyone has some free time and would like to make a nice schematic and maybe even a board so everyone can etch it that would be really nice.

also I have not put any protection on the rpm signal coming in from the car, I figure the atmega chip isnt that expensive so if you blow it up no biggie but if anyone wants to design a bit more refined circuit you are more than welcome. just give me the changes and I will add it to the zip file.

critter

iTrader: (9)

Sorry, but I have used Mot since the 6800. I've seen no reason to switch either.

SupahRich

iTrader: (14)

Nice, thanks for all the work you've put in to this so far... just to share with some board members I have several projects going on right now but as soon as I can get some spare time I'll see if I can get one put together. Don't believe I'll need one for my 5177 kit but it would be nice to have in the future (not to mention the educational value of putting one together).

Thanks

Geo.

Cool of you to make this available.

critter

iTrader: (9)

No body has addressed this. I guess the guys that know want you to figure it out for yourself like they did ...

I wonder if 1K Hz isn't too high for those solenoids. The old one I have looks like a lot of mass to move that fast. It will take some experimenting.

Technoman64

iTrader: (6)

"also I have not put any protection on the rpm signal coming in from the car, I figure the atmega chip isnt that expensive so if you blow it up no biggie"

No biggie for the chip, what about the car and driver if the controller turns the solenoids on 100% and leaves it there?

BMN

LOL, I just logged on to say the same thing and saw u beat me to it.

sbr523

the protection for the atmel chip isnt that important, the car has protection on the rpm signal wire so you can't realistically hurt it, the mosfet switch will always fail to open so if something happens to the atmel chip the system will just quit working. if you want to be extra safe you can always wire 2 mosfet switches in series so there is no chance that both will fail at once. to protect the atmel chip an optoisolator could be hooked up on that signal but really isnt necessary considering the chip is less than 10$ from most places

http://www.diy-nitrous.fsnet.co.uk/n...electrical.htm is another circuit you guys can build that is a progressive controller. That one is well tested and built by many people. He says run the solenoids around 10-100hz so I will change the speed and update it in the zip file tonight when I get back home.

I know a lot of the guys who are selling things on this board probably will not like this system but it is a d-i-y system so it is for us hardcore nuts who like to make all the parts on their own, (I even made my own air lid out of fiberglass) I figure most people will be perfectly happy buying parts to make their cars fast but some of us like doing things the hard way for some strange reason.

I have no way to test this system out considering there is 6 inches of snow and my car can barely get out and about normal. I also haven't installed anything on that kit car and even if I did it is not in anywhere near good enough condition to handle that much power yet. as for my camaro I haven't even got the first part for adding nitrous to it.

sbr523

I changed the output frequency to 30hz and it seems to work pretty good at that speed, I don't have any nitrous so that is about all I can figure on it for now.

I guess I need to get some good weather and Ill get to try some of this stuff out. maybe next month

Geo.

Not saying that it couldn't be a problem , but I'm thinking that you'd keep the WOT switch in series, and you could also pulse only one of the two solenoids on a 5177 kit. So even with a catastrophic failure, at least you'd still have on/off operation.

BTW, as 2 cents from the peanut gallery, I'm guessing that 1Khz is probably too fast, too. My only point of reference is those little reed relays that take on the order of 1msec or so to switch and stop bouncing. I'd imagine the big nitrous solenoid would take a few times that (or more?), so your new 30 Hz rate (33msec period) is probably better. I see you updated the .HEX files, hopefully that includes your code updates. Looking forward to seeing someone actually build and implement this thing. If nothing else, I'm inspired to learn a little more about microcontrollers :-).

Technoman64

iTrader: (6)

"the protection for the atmel chip isnt that important, the car has protection on the rpm signal wire so you can't realistically hurt it, the mosfet switch will always fail to open so if something happens to the atmel chip the system will just quit working."

What if the Atmel chip latches its output on at +5V. The MOSFET would then be on. You need some type of protection and/or logic circuitry to prevent this from happening. Are you saying that if the chip were to fail and latch the MOSFET on it is not a problem. What if the guy is on the street with other motorists? The output from the MCU can be either high or low when the failure occurs and can latch in that state.

Build it as you like, just remember hindsite is 20/20. If you can do a DIY controller more power to you. Just be safe and keep other motorists in mind. Always have a main arming switch to kill all power. My point is that if you do not have any circuitry to protect the MCU it will most likely fail at some point. In the time it takes to get to the main arming switch disaster can happen. All electronics are prone to failure. If you take no precautionary steps to prevent spikes, ground faults, low battery conditions I think you can plan on problems occuring.

Just my .02 worth. Not trying to stop you from building a controller just would like to see you build a safe one. That does not mean I will give up my knowlegde that took me years to learn. And yeas I am slow learner

sbr523

one thing I forgot to mention is that I have 2 voltage inputs on the circuit, one powers the microcontroller and the other powers the output, I planned on everyone running their system as normal and just hooking this inline. So that means the wot, fpss and master arm switch will all still be hooked up. I figure this is as safe as it can be made. in the unlikely event it fails to on then you will probably get wheelspin if it was still ramping up and goes instantly to 100%. The natural thing to do when the tires are spinning uncontrollably is to let off the gas and that breaks the circuit.

I don't have enough trust in a microcontroller to let the controller monitor everything and cut it off on its own (be real easy to add a tps sensor and other inputs to it.) I would always want to have a manual switch hooked to the gas pedal so that it takes no effort to cut off the system in case of a problem. so the choice in mosfet switches was to make sure the circuit could be hooked up inline to the existing system just like adding another relay or switch.

Geo.

I editied my previous post to say "WOT switch" instead of "TPS switch" to clarify.

BTW, I think Harlan's (y2kHawk) shift light (and I assume the RPM window switch) uses an atmel microcontroller, and it's been hanging off my RPM signal line for something like two years now. Maybe something could be learned from that.

SBR253: Maybe you could PM him and ask him if he had any type of buffering for the RPM signal or other suggestions. At the prices he sells them for, I don't think he's out to make a ton of money, so he might be willing to offer suggestions. He managed to get the board for his shift light into a plastic tube about 1" in diameter, and used a pretty neat method of programming using dip switches and blinking the LED to verify the shift point. Sorry I didn't mention that earlier

sbr523

I have had this system hooked to my car for about a week now, when I was first starting the only thing it did was display the rpms, I updated it a few days ago and added the controller features and set the rpms to start at 1000 and max power at 1500 with a cutoff of 2000 and hooked it up to a standard 1157 bulb. The bulb does what it is supposed to do whithin the limits that it is possible to tell what a bulb sitting in the passenger floor is doing while I am driving. hooking something to it like a scope would give more information but I probably would wreck trying to read it while driving so I figure that is a bad idea.

I have no possible way of testing it with nitrous till the weather breaks probably in march. I can use most of the parts I have around for my kit car and make a simple dry shot with something like 100hp output and measure the g forces as I accelerate to see if the controller is doing what it is supposed to do.

This weekend assuming I get time I am also going to try and work on the documentation of the project and stuff like a parts list so it is easier to order the components to build it. If I get lucky I will be able to get this thing done and tested in the next few weeks and can call this project finished, at least until version 2.0