mobythevan Posted March 3, 2006 Share Posted March 3, 2006 After deciding to get the LC-1 wideband unit I decided that I wanted one programmable output to run megasquirt and the other programmable output to run a gauge. It turned out very useful to have a fulltime AFR gauge when Nelson took the turbo 240z 1500 miles and the fuel filter clogged up. It was easy to see the car was starting to lean out. The most popular option is to use a narrowband gauge which expects a 0volt to 1 volt input. So you set up the LC-1 to output a 0-1v signal and your set. Except that you only have an LED bar or LED circle type gauge. You can buy a digital voltmeter gauge and have a readout in digits, but it just didn't satisfy me. So I ordered some parts last night to build a 3 digit AFR display very similar to the LD02 from techedge. I have schematics for the LD01 display, but they no longer sell it and I'm not sure how the LD02 is built, but from reading their site they changed the LD02 to use RS232 communications with the wideband computer. The LD01 display used a microprocessor, but I didn't want to monkey with code writing and programming. The part I ordered is a dedicated analog to digital converter that drives 3 digit displays. I don't want to get everyones hopes up yet until I get it built, but initially it looks like I could build 3 digit displays with enclosures for less than $30, depending on how elaborate the enclosure is. These would work with any wideband that has programmable outputs like the LC-1. I'll keep everyone updated and post some pics when I get the parts in. you can look at the LD02 on http://www.wbo2.com Quote Link to comment Share on other sites More sharing options...
mobythevan Posted March 8, 2006 Author Share Posted March 8, 2006 I ordered the LC-1 wideband today. I got the parts in to build the display, more updates to follow. Quote Link to comment Share on other sites More sharing options...
Guest 73Turbo240z Posted March 8, 2006 Share Posted March 8, 2006 <~~~ interested... a/f in LED is fun... but solid numbers are better! Quote Link to comment Share on other sites More sharing options...
tannji Posted March 19, 2006 Share Posted March 19, 2006 Bump? Quote Link to comment Share on other sites More sharing options...
woldson Posted March 19, 2006 Share Posted March 19, 2006 Very interrested. Since i dont have the money yet to get megasquirt for my 83 280zx, and i had to use the car money to repalce96 saab turbo auto tranny, my z did not pass emmisions. just being able to tune it a little can get me through. it would be a great tool for many different things and not the huge cost!!!!!1 Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted March 20, 2006 Share Posted March 20, 2006 just use a wideband.. and a voltmeter.. set the LC-1 for 0v=10AFR 5v=20AFR so 1.15 volts = 11.5 AFR etc Quote Link to comment Share on other sites More sharing options...
mobythevan Posted March 20, 2006 Author Share Posted March 20, 2006 Prox, that will work fine using the voltmeter. I just wanted a display that was a little bigger and more custom looking. I have started construction of the circuit in breadboard format. I have just run out of time this week. My wife's business is really going well, so I am adding two more 10x20 loafing sheds and various other projects. I'll let you guys know when it is working, I have the LC-1 in hand now. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 20, 2006 Author Share Posted April 20, 2006 I haven't forgot about this. I got the LC-1 wideband installed and working with MSnS. Today I ordered the rest of the capacitors and resistors from Jameco to finish building the display. Quote Link to comment Share on other sites More sharing options...
dj paul Posted April 20, 2006 Share Posted April 20, 2006 it is cool what your doing, but you could just use a nice digital voltmeter. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 21, 2006 Author Share Posted April 21, 2006 but you could just use a nice digital voltmeter I checked on them but a nice one runs around $200 and you know me, cheap b@stard. Its more of an exercise to play around with. And the digital voltmeter will have the decimal in the wrong place, picky picky, I know. Now I just need to find a nice looking cheap enclosure for the big seven segment display. Quote Link to comment Share on other sites More sharing options...
Guest 73TPIZ Posted April 21, 2006 Share Posted April 21, 2006 ..........you know me' date=' cheap b@stard. .............. And the digital voltmeter will have the decimal in the wrong place, picky picky, I know. ................[/quote'] I thought that's what Sharpie's are for. BTW, are you and the neighbor planning anything for Thanksgiving? JK :) Forgive me, I'm feelin' typee tonight. Take care, Quote Link to comment Share on other sites More sharing options...
eec564 Posted May 3, 2006 Share Posted May 3, 2006 You don't need to spend 200$ to get an accurate multimeter. For 40$ plus tax/shipping you can get a very nice basic meter from Jameco. It's the Metex M-3800, I've used them for a long time and they've always been great. Very accurate, measures resistance, voltage, current up to 10 amps unfused, 2 amps fused. Search for 3800 from jameco.com, or follow this link. http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=27115 Quote Link to comment Share on other sites More sharing options...
mobythevan Posted May 3, 2006 Author Share Posted May 3, 2006 I want a display that looks nice in the dash like the LD02 I don't want a cheap multimeter setting on the dash, fine for testing purposes, but not my choice for long term in dash gauge. I am not knocking that solution, that is great to get started and set up the car, I am just looking for a "cheap" nice looking solution. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted May 3, 2006 Author Share Posted May 3, 2006 BTW, the circuit is built and works as advertised. As soon as my car is running again I will test it connected to the LC-1. Then I can build an enclosure like pictured above (LD02 style). Quote Link to comment Share on other sites More sharing options...
blake culp Posted May 3, 2006 Share Posted May 3, 2006 Where did you order your dedicated analog to digital converter ? I have the lc1 too, and the standard af ratio guage i have just doesnt cut it(anything richer than about 13.0-1 it reads full rich) driving around with my laptop and ms running sucks too. For thirty bucks, ill definately build one. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted May 3, 2006 Author Share Posted May 3, 2006 I got the TC7117 from jameco, around $3. I also ordered the supporting parts from them. Download the data sheet and build according to the typical application on page 3, but make sure to substitute the correct values for 2 volt full scale operation. I turned on the decimal point to allow it to read AFR correctly and set AFRs from LC-1 to be 1v = 10AFR and 2v = 20AFR It uses 7 segment LEDs and they wire directly to the A/D with no other components. The circuit will then readout 10.00 for 1 volt and maxes out at 19.99 for 1.999 volts. It has a potentiometer to calibrate, I calibrated by using my multi-meter to read the input voltage. It requires quite a bit of wiring on the breadboard and will be fairly busy on a perf board. I am going to look at proto-typing boards that may have most of the 7 segment buses already there. Cost of all parts to build the circuit was less than $10 for me. The issue right now is that it requires -5volts so I need another regulator for the standalone gauge My breadboarding setup has -5v so it works in there. Just something fun to play around with. Figure 5.1 in the datasheet shows how to build the -5volt regulator circuit Quote Link to comment Share on other sites More sharing options...
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