Search found 137 matches

by mobyfab
Wed Apr 09, 2014 9:05 am
Forum: Hardware
Topic: let's choose an enclosure
Replies: 88
Views: 12663

Re: let's choose an enclosure

by mobyfab
Fri Apr 04, 2014 2:47 pm
Forum: Hardware
Topic: analog inputs: op-amp + divider - Russian - now MCP6004
Replies: 126
Views: 35586

Re: analog inputs: op-amp + divider - Russian - LMV324IDT

I see :)

Yeah the ADC has 1kohm/8pF input so it should not affect it too much.
by mobyfab
Fri Apr 04, 2014 2:22 pm
Forum: Hardware
Topic: analog inputs: op-amp + divider - Russian - now MCP6004
Replies: 126
Views: 35586

Re: analog inputs: op-amp + divider - Russian - LMV324IDT

Why did you put the divider after the opamp ?

The higher output resistance might affect the ADC. (but no much)
by mobyfab
Fri Apr 04, 2014 2:10 pm
Forum: Software
Topic: Knock sensing and Serial USB in software
Replies: 10
Views: 3216

Re: Knock sensing and Serial USB in software

Sergey89 wrote:TPIC8101/HIP9011 for example has a sampling frequency about 200 kHz. Who knows what is the reason of a choice this frequency ?
With a higher frequency you get better precision, and you can take harmonics into account, to avoid false positive.
by mobyfab
Thu Apr 03, 2014 2:39 pm
Forum: Software
Topic: Knock sensing and Serial USB in software
Replies: 10
Views: 3216

Re: Knock sensing and Serial USB in software

Latency or being out of sync should not be an issue since we are running an RTOS.
Unless things are done really wrong.

This MCU has DSP instructions, it would be a shame not to use them :)

There is probably a way to implement the Goertzel algorithm using DSP as well.
by mobyfab
Wed Apr 02, 2014 12:30 pm
Forum: Software
Topic: Knock sensing and Serial USB in software
Replies: 10
Views: 3216

Re: Knock sensing and Serial USB in software

Indeed, Git support in Windows sucks. I only use command line which I feel is what works best. (Linux and Cygwin for windows) TortoiseGit stopped working for me, so it's not an option. MsysGit works pretty well. SVN is so limited for team work that I think sticking with it is will make you loose a l...
by mobyfab
Wed Apr 02, 2014 11:07 am
Forum: Hardware
Topic: Power supply - kb1gtt
Replies: 212
Views: 38109

Re: Power supply - kb1gtt

I'm looking at that sky-macau company as they offer this inductor http://www.sky-macau.com/Keyword-Search/C-0/k-3817361683/ the design uses 2X of them. Which costs about $1. The design should be posted shortly, and I'll be looking for people to review it. That company didn't have the catch diode I ...
by mobyfab
Wed Apr 02, 2014 9:42 am
Forum: Hardware
Topic: Power supply - kb1gtt
Replies: 212
Views: 38109

Re: Power supply - kb1gtt

For the LDOs, the thing is that often OEM ECUs are potted so they have a much better thermal coef. 80-90% from a non synchronous at low output voltages ? Optimistic. Datasheet shows 74% for 14v -> 3.3v, and 81% for 14v -> 5v. Diode's Vf is a big problem at low voltages. For the cost, you will save s...
by mobyfab
Tue Apr 01, 2014 2:06 pm
Forum: Software
Topic: Knock sensing and Serial USB in software
Replies: 10
Views: 3216

Re: Knock sensing and Serial USB in software

That was quick!

1) I could give a hand if you were using Git. :P

2) You probably need to play with the VBUS to force windows to reconnect. Also might need some delays.

3) Git is really as easy as SVN if you don't do crazy branching. It's just a mater of getting used to it.

Thanks :)
by mobyfab
Tue Apr 01, 2014 1:43 pm
Forum: Software
Topic: Knock sensing and Serial USB in software
Replies: 10
Views: 3216

Knock sensing and Serial USB in software

Hi, It seems most of the tasks are done on hardware, such as knock sensing and additional serial to USB. Why don't you do these in software? To me, knock sensing is simply calculating FFT on a buffer, and measuring the value of specific bins (frequency). Of course there are a few other things to do ...
by mobyfab
Tue Apr 01, 2014 1:26 pm
Forum: Hardware
Topic: Power supply - kb1gtt
Replies: 212
Views: 38109

Re: Power supply - kb1gtt

If you are gonna go for a DC converter, go for a synchronous, high frequency one.

For example: http://www.ti.com/product/lm25117-q1

Else just stick to an LDO for low ripple.

Going for an old converter like the LM2596 is really not the best option IMO.
by mobyfab
Tue Apr 01, 2014 1:01 pm
Forum: Software
Topic: RTOS options
Replies: 33
Views: 10088

Re: RTOS options

Ya, all the major MCUs used today by OEMs (SH, tricore, MPC56, etc.) have bad ass TPU units designed to offload a lot of the timing sensitive stuff. The TPU is almost as much silicon as the MCU in some of the newer Renesas designs. The TMS570 looks promising too, but the price on it is pretty damn ...
by mobyfab
Mon Dec 16, 2013 9:25 pm
Forum: Hardware
Topic: Power supply - Sergey89
Replies: 20
Views: 6771

Re: Power supply - Sergey89

I would use something like that: http://www.ti.com/product/tps54239e

Compared to an LDO you just need to add a tiny inductor. (3x3mm)
by mobyfab
Mon Nov 25, 2013 10:04 am
Forum: Hardware
Topic: What about fancy output drivers?
Replies: 12
Views: 2857

Re: What about fancy output drivers?

It's a very specialized chip so I guess only big companies buy them in huge quantities... that's why.

It's the perfect chip (infineon has a few others) but it's almost impossible to buy at low quantities.

I had found that chip a while ago, but impossible to buy in europe...
by mobyfab
Sat Nov 23, 2013 12:16 am
Forum: Hardware
Topic: CAN bus
Replies: 18
Views: 4231

Re: CAN bus

You can get an OBD2 connector on site like ebay.

You will need a CAN transceiver such as the MCP2551 or the newer MCP2562 (for 3.3v compat) between the CAN pins of the STM32 and the bus lines.
by mobyfab
Tue Nov 19, 2013 1:26 am
Forum: Hardware
Topic: VR + knock module
Replies: 37
Views: 11031

Re: VR + knock module

Why not use a simple buffer + DC bias to the ADC and do the rest in software?

The F4 has DSP capabilities so it's totally possible.
by mobyfab
Tue Oct 29, 2013 10:12 am
Forum: Software
Topic: wideband AFR sensor interface
Replies: 21
Views: 5359

Re: wideband AFR sensor interface

http://www.14point7.com/

They have some really nice units.

Also there is the AEM UEGO which I've been using for a few years with my turbo civic, very good and the price it not that high.