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#1
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Switching 52 channels with one switch
Is there any way, simply and cheaply, that i can find a physical switch
to swap between two wiring looms on an ECU for a car? Theres 52 individual channels (all 0-12v DC, no massive currents, some are noise sensitive such as the knock sensor). Any help appreciated. |
#2
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On 30 Sep 2005 06:12:00 -0700, "Coyoteboy"
wrote: Is there any way, simply and cheaply, that i can find a physical switch to swap between two wiring looms on an ECU for a car? Theres 52 individual channels (all 0-12v DC, no massive currents, some are noise sensitive such as the knock sensor). Simple, but not cheap: http://www.electronicsurplus.com/com...=1128098066804 Also: www.electroswitch.com -- John Fields Professional Circuit Designer |
#3
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How about using some of the national semi analog cmos switches?
They have a quad SPDT and several SPST types. The "on" resistance can be a few ohms and vary some with temperature - so they are not suitable for low impedance loads, but can drive loads like an opamp input. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#4
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Hmmm, i liked the look of that until i saw they have an on resistance
of 300ohms, a bit much i think. J default wrote: How about using some of the national semi analog cmos switches? They have a quad SPDT and several SPST types. The "on" resistance can be a few ohms and vary some with temperature - so they are not suitable for low impedance loads, but can drive loads like an opamp input. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#5
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yeowch, you arent kidding on the not cheap lol. Hmm, im going to work a
less expensive way round this lol. J |
#6
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On 4 Oct 2005 06:40:50 -0700, "Coyoteboy"
wrote: yeowch, you arent kidding on the not cheap lol. Hmm, im going to work a less expensive way round this lol. --- 26 cheap DPDT relays? -- John Fields Professional Circuit Designer |
#7
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On 4 Oct 2005 06:39:40 -0700, "Coyoteboy"
wrote: Hmmm, i liked the look of that until i saw they have an on resistance of 300ohms, a bit much i think. Yeah, I know it looks bleak - but if you're feeding a high impedance input, what is 200-300 ohms when inputted to a amp that has a 10 meg ohm impedance or better? You won't notice the voltage 300 ohms drops. I used three stages of them rated at 200 ohms into a 747 quad op amp and there was no noticeable loss of signal voltage. Your thinking digital - we analog designers "match the hatch" (a fly fisherman's term - meaning you put out what they will bite - because they are biting it already - your fly matches the current hatches of flys) It shouldn't be dismissed until you weigh the alternatives - perhaps a unity gain op amp on each switch would make the resistance go away? You know what impedance you need to match . . . I don't. -- ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#8
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default wrote: On 4 Oct 2005 06:39:40 -0700, "Coyoteboy" wrote: It shouldn't be dismissed until you weigh the alternatives - perhaps a unity gain op amp on each switch would make the resistance go away? You know what impedance you need to match . . . I don't. Im seeing your point, however im not sure what impedance i have to match either. I know that im swapping over engine control from one ECU to another, i know the resistance of some of the connections are to sensors and are in the range of 0-3K, and some are connections to coils of unknown resistance but that could be found out, and one is the knock sensor, tuned to about 7KHz. The main problem is that the ECU is a slighly unknown quantity as far as components, amps etc. I really wanted a black-box-direct switching setup - any real resistance is going to have possible implications i cant calculate for. Appreciate your ideas though, i'll have some more thoughts around the idea. J |
#9
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you know i am thinking this might be the best option in the end LOL.
Bit bulky but at least it makes a nice simple low resistance solution. J |
#10
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On 4 Oct 2005 16:36:22 -0700, "Coyoteboy"
wrote: default wrote: On 4 Oct 2005 06:39:40 -0700, "Coyoteboy" wrote: It shouldn't be dismissed until you weigh the alternatives - perhaps a unity gain op amp on each switch would make the resistance go away? You know what impedance you need to match . . . I don't. Im seeing your point, however im not sure what impedance i have to match either. I know that im swapping over engine control from one ECU to another, i know the resistance of some of the connections are to sensors and are in the range of 0-3K, and some are connections to coils of unknown resistance but that could be found out, and one is the knock sensor, tuned to about 7KHz. The main problem is that the ECU is a slighly unknown quantity as far as components, amps etc. I really wanted a black-box-direct switching setup - any real resistance is going to have possible implications i cant calculate for. Appreciate your ideas though, i'll have some more thoughts around the idea. J I don't know how much hassle it is, but one option would be to insert some resistance into each signal lead - say a 1K ohm or so. If the ECU performs like normal, you know your analog switches won't cause a problem. -- ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#11
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On 30 Sep 2005 06:12:00 -0700, "Coyoteboy"
wrote: Is there any way, simply and cheaply, that i can find a physical switch to swap between two wiring looms on an ECU for a car? Theres 52 individual channels (all 0-12v DC, no massive currents, some are noise sensitive such as the knock sensor). Any help appreciated. Hold the phone . . . How about using switches? It would take (say) three banks of roller arm or lever arm microswitches. Three banks would be about four inches long each. You could manually transfer the connections with a single lever that would slide three bars against the switch arms compressing them and actuating the switches. If it needs to be under remote control, I'd use something like those new "solenoids" that are appearing in cars. They are a motor driven plunger with a high gear ratio and about a one inch travel. A lot of torque . . . something most solenoids lack - and they don't require power after switching. A pair of extra switches in the banks could be used to limit the travel of the plunger - like the "zero seeking" mechanism used in windshield wipers. The switches have power applied to move plunger in one direction or the other and it travels until it switches itself off. The whole switch assembly would take up about 4" X 4" X 1" excluding actuator. The same idea could be applied to these little 1/4" SPST snap action board mounted "reset" switches. Two banks of 52 switches with a mechanical either-or actuator. My guess is the SPST switches would be cheaper ten cents versus a dollar for a microswitch, but the mechanical actuator would be easier with a microswitch. -- ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#12
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On 4 Oct 2005 16:38:50 -0700, "Coyoteboy"
wrote: you know i am thinking this might be the best option in the end LOL. Bit bulky but at least it makes a nice simple low resistance solution. --- Digi-Key's got an Aromat JW2SNDC12V: http://pewa.panasonic.com/pcsd/produ...pdf_cat/jw.pdf for $2.41 each, qty 26. -- John Fields Professional Circuit Designer |
#13
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Switching 52 channels with one switch
I would of course, be sure that the car is turned off while switching... going from input to no input, or partial input may cause issues (damage) to the ecu, or the sensors (map or mas),,,, just a thought... Bob in phx "default" wrote in message ... On 30 Sep 2005 06:12:00 -0700, "Coyoteboy" wrote: Is there any way, simply and cheaply, that i can find a physical switch to swap between two wiring looms on an ECU for a car? Theres 52 individual channels (all 0-12v DC, no massive currents, some are noise sensitive such as the knock sensor). Any help appreciated. Hold the phone . . . How about using switches? It would take (say) three banks of roller arm or lever arm microswitches. Three banks would be about four inches long each. You could manually transfer the connections with a single lever that would slide three bars against the switch arms compressing them and actuating the switches. If it needs to be under remote control, I'd use something like those new "solenoids" that are appearing in cars. They are a motor driven plunger with a high gear ratio and about a one inch travel. A lot of torque . . . something most solenoids lack - and they don't require power after switching. A pair of extra switches in the banks could be used to limit the travel of the plunger - like the "zero seeking" mechanism used in windshield wipers. The switches have power applied to move plunger in one direction or the other and it travels until it switches itself off. The whole switch assembly would take up about 4" X 4" X 1" excluding actuator. The same idea could be applied to these little 1/4" SPST snap action board mounted "reset" switches. Two banks of 52 switches with a mechanical either-or actuator. My guess is the SPST switches would be cheaper ten cents versus a dollar for a microswitch, but the mechanical actuator would be easier with a microswitch. -- ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#14
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Switching 52 channels with one switch
of course, i was ahead of you there What i have thought of tho is
leaving a large number of them connected to both ECUs, and only switching a few vitals with relays. J |
#15
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Switching 52 channels with one switch
What ECU are you using? (ie. Honda P28/P72, LS-1, etc.)
Did you mean so you can switch between two ECU/PCM's or two actual engine/car harnesses? Not sure why someone would want two seperate engine/car harnesses.. so I'm assuming at this point you want to switch between two ECU's.. in which case, it may be much cheaper to simply change out a EPROM. But, not to distract from my question.. what ECU/PCM is this? "Coyoteboy" wrote in message ups.com... Is there any way, simply and cheaply, that i can find a physical switch to swap between two wiring looms on an ECU for a car? Theres 52 individual channels (all 0-12v DC, no massive currents, some are noise sensitive such as the knock sensor). Any help appreciated. |
#16
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Switching 52 channels with one switch
Its to control the same engine with two seperate ECUs - they are Toyota
ECUs for the 3sGTE engine, ones a '91 UK ECU and the other is a '93 Japanese - Jap runs higher boost ability, advanced timing and better fuel maps and requires higher RON fuel - hence i wanted to just switch between them for in case i cant get to premium fuel. J |
#17
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Switching 52 channels with one switch
On Thu, 13 Oct 2005 04:52:41 -0700, Coyoteboy wrote:
Its to control the same engine with two seperate ECUs - they are Toyota ECUs for the 3sGTE engine, ones a '91 UK ECU and the other is a '93 Japanese - Jap runs higher boost ability, advanced timing and better fuel maps and requires higher RON fuel - hence i wanted to just switch between them for in case i cant get to premium fuel. Google around for "rotary switches". You can get them with an arbitrary number of poles - you just stack up the wafers. It would be a little unwieldy, however - howcome you can't just unplug one and plug in the other one? Good Luck! Rich |
#18
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Switching 52 channels with one switch
I think a 52 pole rotary switch could be a little unwieldy indeed
but i'll check them out too. I cant just unplug and replug as the ECU pinouts are very different. I'm currently trying to find some male and female ends to match the ecu ports but i think they are specific to the ECU and so i might have to resort to getting a third ECU and rippign it apart for the connectors lol. J |
#19
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Switching 52 channels with one switch
On Sat, 15 Oct 2005 16:10:44 -0700, Coyoteboy wrote:
I think a 52 pole rotary switch could be a little unwieldy indeed but i'll check them out too. I cant just unplug and replug as the ECU pinouts are very different. I'm currently trying to find some male and female ends to match the ecu ports but i think they are specific to the ECU and so i might have to resort to getting a third ECU and rippign it apart for the connectors lol. Get yet another third type of connectors. If I understand you correctly, you already have one of each harness connector to plug into each of its respective ECUs, right? So find any old 52-pin connector, and buy one female and two males, and map the pins however you want to. I think you can even get male IDC's, if that's applicable at all. Good Luck! Rich |
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