This will be the exact same size and have the same connectors so it
will be interchangeable with a real Megasquirt card.
The size is 4 by 6 inches.
Paul Lamar
Looks good.
Perhaps adding a Bluetooth chip (cost $1) would allow us to connect our
laptop/tablet without wires. My GPS receiver is Bluetooth and has
performed flawlessly on every flight.
Not sure what schematic/PCB program you are using, I have found
DesignSpark to be excellent, it is free yet not locked into one PCB
manufacturer thus output can be manipulated in many ways. If you design
via schematic it features an auto PCB layout if you wish.
Terry Adams
KSCK
Great idea. I'll take a look at it depending on the real estate.
I am using a crude free one called ExpressPCB.
Thanks for the tips Terry.
Paul Lamar
As you work on designing the new board, if you choose or need to use any
SMT components and would like to fabricate a prototype perhaps I can
offer my assistance in reflow soldering the board for you. I can handle
MSOPs, but I do not like DFN/QFN components unless they have edge
exposed pads.
Terry Adams
KSCK
Thanks Terry. I'll keep that in mind. I think I have enough real estated to do the
old fashion dips. When you get right down to it it is pretty simple without all the
injector damping stuff. Here is the schematic.
Paul Lamar
Why not reprogram the ego input to scale the ve tables between some appropriate
values. Then you could use a pot to lean the mixture. This way, you can calculate
more accurate fuel burn off the injector on time than if you were varying the fuel
pressure to control mixture.
Josh
I will have to study that Josh. Thanks for the tip.
How are you with 68 asm programming?
BTW when I eliminated the low impedance injector damping I got rid of half a dozen
power transistors. The board is beginning to look empty :) B&G threw everything into
this board including the kitchen sink :) I guess they did it to cover as many
different piston engines as possible. There are also several options for CAS types.
Here is the the current iteration. I am trying to keep the component labels the same
as the megasquirt boards. I also have an assembled V2.2 board coming in from
DIYautotune this week. I'll be able to compare that with the V3 MB which I have
access to no less than three. One bare and two populated. The two loaned to me by Ed
Carver are populated and have the daughter card with the MC9S12C64 processor. The
band aid for the slow, bloated C version of the software :)
Paul Lamar
I've always been an indifferent programmer, and I have 0 experience with 68 asm. I
could probably muddle through it and end up with something that works though. Are you
looking for someone to make modifications to the MS source?
I've been thinking, and it may make more sense to use something like the TPS input.
MS has a neat built in tuning feature if you hook up a wideband. It would be a shame
to give up that capability. The TPS on the other hand probably isn't necessary for AC
use as it is mostly concerned with throttle response. I am assuming that you have no
other inputs that are unused in your setup.
Josh
Mostly for some one to collabrate. Two heads are better than one. Most of the time
the other guy has a better idea :) I have got to come up with a routine that
calculates the coil dwell time compensation as a function of RPM. The idea is turn on
the current in the coil 2 or 3 ms before you need the spark to fire.
We can connect the O2 sensor as long as you are running no lead auto gas.
A switch somewhere can turn it off and on. 100LL destroys O2 sensors.
We got 8 channels of A to D and we are using only six.
Paul Lamar
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