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^. You'll need a bit more than a step down. Automotive '12V' rail is electrically very noisy and can vary between 3 and 15V.
You'll have to factor in transient suppression and the dreaded 'load dump'. In any automotive design involving low voltage microcontrollers, this is a challenge. You can easily get transient voltages of 50+ V which will readily kill your electronics. At best, you will experience random resets and other 'glitches'. There are several approaches built from discretes but probably the easiest is to adopt a proper PMIC (that's what our CDI+ has). Here's a data sheet for a typical protection device. I am not saying use this one, but it describes the sort of conditions you will be facing. http://www.ti.com/lit/an/snva681a/snva681a.pdf |
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1. 12 volt input to 1N4004 to 15 ohms followed by transient suppressor (22 volts) to ground 2. 100 uf @ 35V capacitor to ground and 5V regulator (78L05) input 3. 5 volt regulator output to 47 uf @ 10V (tantalum) to ground with regulator output for microcontroller power 4. regulator third pin grounded It's that simple. |
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78L05? I think he's gonna need more than 100mA with that display. Never seen any 7805 in any production design ever. Might be ok for proof of concept on the bench but not for anything proper. LM2937 is a better choice. I suggest the OP looks at the power supply for something like Megasquirt. This project granted is just a bit of fun but if you're even remotely thinking of making this into a product you have to work on the basis that the installer/operator is a complete idiot. The car will get started on a booster, things will get connected wrongly, power supplies backwards, you name it, it will happen. Thinking about this stuff now will save you a world of pain in the long run. Just my $0.02. |
Thought about 3d printing a bezel?
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Wow what an ambitious project, more power to you!
In my Targa I have no need for any AC setting other than MAX; one switch puts 12v on the monster GM fan, and another switch goes to the AC compressor clutch. I too have removed the console and love the look without it. Chuck.H '89 TurboLookTarga, 422k miles |
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Specs: Basic properties:https://www.neweggbusiness.com/Product/Product.aspx?Item=9SIV0GP3AZ0023&nm_mc=KNC-GoogleBizMKPL-PC&cm_mmc=KNC-GoogleBizMKPL-PC-_-pla-_-Power+Strips+-+Inverters+and+Converters-_-9SIV0GP3AZ0023&gclid=COGD1JPR7M8CFQZafgodLg8CYA Quote:
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Center console... the more I don't see it onboard, the more I don't want to see it onboard! Interior "cleans up" very nicely without it. Question is, where would controls and display go without console? I have Kuehl center vent (where bow tie was) so don't want to mount AC controls below dash at center. Don't want to put in glove box. With Targa... can't go overhead. Would very much like to see pic of your interior configuration---in particular... where are your AC controls located?!?! |
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Little difference to the LM2937 when proper input protection circuitry is used. |
Rubber molding media is 2-part soft putty. Product: EasyMold.
http://forums.pelicanparts.com/uploa...1477138947.jpg Testing for any undesirable reaction between materials and for release of rubber from clay. http://forums.pelicanparts.com/uploa...1477139069.jpg 2-3 hour harden time. 24 hour full cure time. No odd reaction and nice release. http://forums.pelicanparts.com/uploa...1477139096.jpg 4D (L) and Nextion (R) 2.8" displays. I may have made a mistake getting touch screen Nextion. Not sure if non-touch Nextion screen reflection would be same but when comparing to 4D non-touch, there's a noticeable difference between the two screens. (Reason for getting touch screen was possibility of developing touch screen items downstream. Given low location of display when in operating position, it now seems a bad idea to be working a touch screen at such a low level.) These displays are so inexpensive so if, after installation, there's any issue with visibility... I'll get a non-touch screen Nextion to see if there's any difference. (Nextion was had from ITEAD. Product shipped from Hong Kong. Took only a few days by postal service.) 4D screen came with bezel attached to it with double sided tape---black tape can be seen in pic. 4D Bezel is flush-fit to Nextion display---precluding further bezel-chasing! How this screen-&-bezel combo will actually preform with the display turned on has yet to be proven. http://forums.pelicanparts.com/uploa...1477139350.jpg http://forums.pelicanparts.com/uploa...1477139854.jpg http://forums.pelicanparts.com/uploa...1477139887.jpg http://forums.pelicanparts.com/uploa...1477139904.jpg |
Anyone that has removed center console and repostioned AC controls... pls post pic.
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Karl,
If you're looking for ideas on how to 'clean up' the interior, here is what I've done. First I deleted the center console. When I did my interior rejuvenation I went with RS carpets. http://forums.pelicanparts.com/uploa...1477142673.jpg But I had to solve the problem of where to relocate the A/C controls. I got the idea to put them in the ash tray location from Fred Cook. Fred went so far as to send me a mock up of what he used in his own car. Ray Morgan (local guy) helped me build a more permanent mount solution and we finished with some of the leftover vinyl I used from the interior job. http://forums.pelicanparts.com/uploa...1477142955.jpg Perhaps you could mount a bezel there. A slightly different approach (albeit a bit more complex) would be to hide the arduino controller someplace (under a seat for example) and then connect to the arduino via Bluetooth to a smartphone. You have all kinds of GUI design choices with Apple & Android SDKs. Plus there is a wealth of development help/info out there. Most people have a great screen in their pocket these days. Here's a pic of what I'm looking at when I'm driving. I use the P-car mount to place my phone within easy view and reach. Sorry for the crappy lighting. I can take another picture in the daylight if that helps. The phone mount is on a ball joint so I can adjust it up/down and left/right if there is any glare. http://forums.pelicanparts.com/uploa...1477143386.jpg |
Another twist on the idea would be to use the P-car mount and pick a mounting bracket for your custom screen from the vast array of choices available. The P-car mount has a universal mounting plate and you can use any type of holder/attachment that matches. There are all kinds to choose from. Take a look at Pro Fit International for a place to start.
Maybe one of these would work... GPS Holders and Mounts for Garmin, TomTom and more Here is a link to PCAR mounts. http://pcarmounts.com Pelican sells them now too. |
^^^ Nice location idea Tim! Am definitely going to explore this. iPhone BT connectivity... in my case that would not always work well---I like being without iPhone on occasion. Display put below or above knobs would possibly work. As I recall, ashtray is off center so a slight dip in the dash there would not be issue (relative to AC center vent below.) Think you hit it Tim. http://forums.pelicanparts.com/support/smileys/wat6.gif
New question is whether or not to pursue this direction now or stay the planned course? Gona ponder before diving in. PS... great work on interior Tim! PSS... appreciate the links. Not for this per se but I save them all the same---future ref. TY This is creative thinking... http://forums.pelicanparts.com/uploa...1477145777.jpg |
Being 'unavailable' and 'without cell phone' are different things. I use the Do Not Disturb feature on my iPhone all the time. There is nothing more distracting than being in a customer meeting giving a presentation and having someone constantly calling and texting.
When I'm driving the 911 I usually turn DND on. For one it would do no good to answer the phone. The car is loud and I like it that way. I have my family's numbers on the exception list. Wife knows I won't answer when I'm driving the 911 unless it is an emergency. (I have BT in my truck.) I use Waze a lot even when I know where I'm going because Atlanta sucks for traffic accidents and I can get a warning to avoid it. Plus I use the Escort radar detector app on my phone. Those are essentials to me. Should you ever decide to make this generally available, I think the BT/Smartphone approach would be best. For one, it would help keep the costs down (less hardware). Secondly everyone has a preferred way of using/mounting a smartphone so this has ultimate flexibility. It also reduces the installation complexity. And finally product life cycle upgrades are greatly simplified. |
^^^ Mounting arm off clock face is a great find Tim... TY for that. I get what you're saying about BT-iPhone combo. I tend to forget phone---and quite frankly am content to be without it at times. So... am switching out iPhone mounted on the "boom" for permanent touch screen---which has functionality at that level compared to being down in console. Not having to fit display into dash also allows a larger screen than is going into console.
Rather than detour here, going to finish as planned---keeping console for the time being. When other projects have been completed, will return to this doing ash tray delete (for knobs) and boom add. "Non-shrink" clay... shrunk. Measurably over just a few inches. http://forums.pelicanparts.com/uploa...1477161415.jpg Will add material to both sides. Saran Wrap liner works well... http://forums.pelicanparts.com/uploa...1477161481.jpg Can remove Saran immediately without distorting clay. If clay had to remain wrapped in it... would take very long time to dry. http://forums.pelicanparts.com/uploa...1477161684.jpg |
All parts have arrived. Handing over to John... possibly tomorrow.
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Parts & Notes File
Photo refs at bottom Graphic Display #1 Nextion Enhanced NX3224K028 - Generic 2.8'' Touch Display Model: IM160511003. Source: ITEAD / $22.40 https://www.itead.cc/nextion-nx3224k028.html For: display/screen part only. Bezel comes from 4D System’s display unit. Mounts: in custom DIY face panel added below existing AC control panel (in center console.) Manufac’s Descrip: Nextion Enhanced NX3224K028 is a powerful 2.8'' HMI TFT display, with 16MB Flash data storage space, 1024 byte EEPROM, 3584 byte RAM. With GPIO supported, now you can use Nextion to control external devices.Includes hardware part (a series of TFT boards) and software part (the Nextion editor). The Nextion TFT board uses only one serial port to communicate. This lets you avoid the hassle of wiring. In the Nextion Editor, the drag-and-drop function ensures that you spend less time in programming, which will reduce 99% of your development workload. With the help of this WYSIWYG editor, designing a GUI is a piece of cake. It's easy to adapt Nextion family HMI to existing projects, you just need to provide it a UART. Note: there's a small power supply test board and a wire for you to test if the electricity supply is enough or not. NOTES: Display screens have varying degrees of reflectivity. In this case, Nextion screen has higher degree of reflectivity than 4D screen. Regardless, ontop of Nextion screen will go solid plastic 4D System bezel---that bezel has high gloss surface. (Perhaps there are spray coatings that would help---have not researched "dulling spray" at this stage.) By adjusting tilt angle of screen, it’s possible to reflect black headliner to driver’s line of sight. TILT: In addition to the console’s 37 degree facia tilt, added display panel tilts back 5.8 degrees. Total tilt-back for display = 42.8 degrees. This angle is particular/unique to driver’s height and proximity to console. Graphic Display #2 4D Systems 2.8” Non-Touch Screen Model: gen4-uLCD-28D-CLB Source: 4D Systems / $49.00 4D Systems | Turning Technology into Art For: Bezel part only. Mounts: On face of Nextion display Manufac’s Descrip: Intelligent 2.8", 240x320 pixel, non-touch display module featuring a cover lens bezel and embedded DIABLO16 processor, which includes a gen4-IB adaptor and 30 way FFC Cable NOTES: Is solid plastic bezel---meaning there’s no center area cut out. This results in a “double screen layer.” How well this will work in terms of working visibility has yet to be proven. Reason for using Nextion display and 4D System bezel is John’s experience with Nextion programming combined with fact that only accurately fitting stock bezel for Nextion 2.8" display is 4D’s 2.8 bezel. In the alternative, 3-D printing a bezel as well as CNC’ing are alternative paths to take. Either would likely cost more than 4D display & bezel ($49 + shipping.) While visual area of 4D bezel matches visual area of Nextion display, this combo has yet been “turned on.” Nextion display (I purchased) is touch-screen capable. This capability is rendered mute by 4D bezel covering touch screen. (Touch-screen was purchased believing "touch" may serve a future interest. Thinking it over, using a touch screen mounted below stock AC control knobs in center console now seems a bad idea. So no longer thinking of any touch capability given display’s current low location. Tim / “Tirwin” referenced an interesting bracket that mounts off instrument panel’s clock face. Were a screen mounted at the level this bracket offers… touch capability would be sensible. See post 71 for Tim’s link / 72 for bracket pic. Microcontroller Arduino Uno Source: DigiKey / $22.00 A000073 Arduino | Programmers, Development Systems | DigiKey For: digital controller Mounts: inside center console cubby on DIY bracket. Power cord permanently attached… USB end dangles from front access hole of console. Make quick-release for AC control panel---panel slides in/out of cubby. Manufac’s Descrip: Arduino Uno is a microcontroller board based on the ATmega328P. It has 14 digital input/output pins (of which 6 can be used as PWM outputs, 6 analog inputs, a 16 MHz quartz crystal, a USB connection, a power jack, an ICSP header and a reset button. Waterproof Temp Sensor DS18B20 / Dallas – One-wire compatible Source: Sparkfun / $9.95 https://www.sparkfun.com/products/11050 http://cdn.sparkfun.com/datasheets/Sensors/Temp/DS18B20.pdf For: Report evaporator core temp to Arduino Mount: in evaporator core (with quick-disconnect terminals located outside evap’s plenum.) Manufac’s Descrip: This sealed digital temperature probe lets you precisely measure temperatures in wet environments with a simple 1-Wire interface. The DS18B20 provides 9 to 12-bit (configurable) temperature readings over a 1-Wire interface, so that only one wire (and ground) needs to be connected from a central microprocessor. Temp & Humidity Sensors DHT21 AM2301 Digital Temperature Module Source: Ebay / $3.14 each For: Report cabin temp & humidity to Arduino Mounts: On interior ceiling behind seats For: Report ambient temp & humidity to Arduino Mounts: behind front bumper Manufac’s Descrip: 1. 4-pin package 2. Ultra-low power 3. No additional components 4. Excellent long-term stability 5. All calibration, digital output 6. Completely interchangeable 7. Long distance signal transmission 8. Relative humidity and temperature measurement Specifications: 1. Type: AM2301 2. Accuracy resolution: 0.1 3. Measurement range: 0-100%RH 4. Temperature measurement range: -40℃ ~ +80℃ 5. Humidity measurement precision: ±3%RH 6. Temperature measurement precision: ±0.5℃ NOTES: At this moment, only three temps affect AC operation. 1.) “Set Temp” (target cabin temperature), 2.) Cabin Temp, 3.) Evap Temp. Ambient and both humidity readouts are presently non-essential bits of info. 2 Potemtiometers, 1 Knob Pot 10K OHM 1/20W Linear Part 987-1649-ND Source: DigiKey / Potentiometer $1.29 each (2 units) P0915N-FC15BR10K TT Electronics/BI | Potentiometers, Variable Resistors | DigiKey For: Rotational selection for cabin’s target temp (“Set Temp” as displayed on screen.) Mounts: in existing AC panel connected to stock temp knob. For: Rotational selection for display’s contrast setting. Mounts: on DIY bracket hidden below dash. Knob: Black/Matte .625” Diameter for 6mmm shaft diameter Part 226-4105-ND DigiKey / $6.10 OEDL-63-4-7 Kilo International | Hardware, Fasteners, Accessories | DigiKey For: Screen contrast knob Mounts: on potentiometer on bracket hidden below dash. NOTES: Reason for this particular model potentiometer is its shaft config---it fits into a Porsche knob (after metal compression ring is removed from knob.) Knob is not perfectly centered on this shaft but… is not noticeable unless one looks very carefully at movement of knob when turning it. Where multiple knobs are positioned in alignment next to each other… and depending on static rotational position of knob, off-center may be evident. Minor mod of parts can center knob on shaft. Relay 2-Channel 12V Relay Module With Optocoupler For Arduino DSP AVR PIC ARM Source: NYPlatform.com / $3.88 2-Channel 12V Relay Module With Optocoupler For Arduino DSP AVR PIC ARM For: 12v Power to AC compressor Mounts: On DIY bracket hidden below dashboard NOTE: Am not sure at this moment if 2nd channel is needed. Serves as spare for time being. Resistors 10 OHM, 4.7 OHM Pic Reference: Graphic display #1 / Nextion 2.8" http://forums.pelicanparts.com/uploa...1477332710.jpg http://forums.pelicanparts.com/uploa...1477332726.jpg Graphic display #2 / 4D System's 2.8" bezel drawing. http://forums.pelicanparts.com/uploa...1477334420.jpg Microcontroller / Arduino Uno with USB power cord http://forums.pelicanparts.com/uploa...1477333195.jpg Waterproof temp sensor / one-wire compatible http://forums.pelicanparts.com/uploa...1477333082.jpg Temp & humidity sensors http://forums.pelicanparts.com/uploa...1477333263.jpg Potentiometers & screen contrast control knob. ("Set Temp" knob is stock Porsche. Compression ring is removed from knob in order to to fit knob on potentiometer's shaft.) http://forums.pelicanparts.com/uploa...1477333352.jpg Relay http://forums.pelicanparts.com/uploa...1477333393.jpg |
EDIT: Forgot to include step down in parts list and cannot add it above as character count is max'd out... so adding it here.
Step Down & Noise Suppressor DC-DC Converter Regulator 12V-5V Step Down Power Module USB Output Perfect #02859812 Source: Mini In The Box / $4.99 --- Did not know this was shipping from China when ordered. Took 9 days USPS. Good online tracking. DC-DC Converter Regulator 12V-5V Step Down Power Module USB Output Perfect 2859812 2016 – $4.99 For: Steps car's 12 volt down to 5v power for Arduino. (Do not like that input wires---12v---are close to 26 gauge.) USB with this unit plugs into USB cable connected to Arduino. See website for pic. Finished clay mold. Leather will cover final resin-casted panel. http://forums.pelicanparts.com/uploa...1477409067.jpg Two-part silicone putty used for 2nd casting. Stuff gets kneaded together. Then 3 minute working time. http://forums.pelicanparts.com/uploa...1477409176.jpg http://forums.pelicanparts.com/uploa...1477409205.jpg In 10 minutes, putty turns to rubber---cured enough to release. Packaging advises 24 hour cure before making resin contact. http://forums.pelicanparts.com/uploa...1477409377.jpg http://forums.pelicanparts.com/uploa...1477409402.jpg Window and mounting ledges for Nextion display need to be sorted into final resin-casted panel. Hacksaw'ing window out and dremeling ledges is one way to go. Less messy and perhaps more direct path is to make second silicone mold that joins existing mold. When resin is poured, display window and ledges will be in place. Gona do a java and think this through. . |
Mold for display's window. Will let both parts cure overnight. Tomorrow will bolt them together... then pour resin. Notch at sides of window mold will be ledge on which display mounts. (If you see window mold being off center on panel mold... it is. Is because display screen is off center on it's backing platform.)
http://forums.pelicanparts.com/uploa...1477439480.jpg |
This is fantastic to watch. Thanks to Karl for posting such a great step by step custom project. I really appreciate the ingenuity and generosity of the people on this forum.
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^^^ Apprciate note... TY Hasti!
John's making killer progress on IT side. Believe he'll be posting soon. I'm continuing progress on display panel. Just went through final casting process. Rubber mold was sprayed with a release conditioner. Special attention was given to leveling perimeter of rubber mold all around. (Rubber is sitting on clay feet.) http://forums.pelicanparts.com/uploa...1477516137.jpg http://forums.pelicanparts.com/uploa...1477516151.jpg 4 screws through display area into face panel makes for tighter joint between these parts. Thin mylar is glued to mold's inside walls. Mylar was also sprayed with release conditioner---whether mylar will release poly has to be seen! No worries if not. Fiberglass went in with poly as "rebar." (Mold was created so Nextion 2.8" display should "just" fit into finished panel. This is a mistake. Should have provided some mounting adjustment up/down. This would have enabled easy fine tuning of display/bezel's final position. Should bezel's position need tuning... will now have to Dremel adjust.) With such small parts having to collaborate, 32nds make a difference. http://forums.pelicanparts.com/uploa...1477516350.jpg Mixed 16 fl ozs poly with 80 drops catalyst. Poured approx. 9 fl ozs. Remainder is used to check cure. http://forums.pelicanparts.com/uploa...1477516625.jpg |
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