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Looking for a circiut board Genius!

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  • Looking for a circiut board Genius!

    I am working on a project and I am needing someone with circiut board design experience. I have a circiut I have put together in expressPCB and need someone to go over it and make it perfect. Let me know if you can help me out. It's worth a few dollars for the job. SNO

  • #2
    Well here is the first phase completed. I am sure there are a few do's and dont's here but I feel pretty good being my first attempt at board design. The goal of this project is to incorporate a few off the shelf items into 1 box and have the option of connecting to a dumb unit, or a PC either via 1 usb cable or multiple serial cables or a combo of both. This box will be around 5x4x1.5 inches and will include OBD2 using the obd200 chip, Phidget 1010 8/8/8 controller, TPMS 433mhz reciever and GPS with external antenna. The GPS unit has ftdi usb/serial/bluetooth. I will be needing about 65 to start with so it should get costs down if anyone might have an interest in a product like this. SNO Click image for larger version

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    • #3
      I'm no pcb expert, but would'nt you want to make all those individual grounds be solid copper instead of traces? My electronics design was in the mid 70's, but they taught us to keep as much copper solid as possible on ground.


      • #4
        If you look at the tips page for the software you are using there are some decent tips there for you.
        And rray's suggestion is in there too..

        Since I am looking to do something similar I would love to hear about your experience.

        How big is your board?

        I will likely go a different route, bread boarding things first to see if they work and going from there.
        Although using "chips" such as the ODB200 and PHIDGET 1010 will save a lot of time.

        Also, you may want to consider in circuit fuses or optical isolation for the inputs and outputs. Unless you are going to make your PHIDGET socketed so it can be replaced.

        Unless they are for specific objects or are fused/isolated elsewhere people WILL hook those to things you don't expect and will blow them...

        Ps, I am a newbie too but have had some "interesting" experiences in the past as I was one of those people that tried to hook up things the designer didn't expect and blew parts up.. Luckily those designers put in circuit fuses that looked like resisters and I was OK... Swapped out a $.02 fuse and was on my way..
        Last edited by redheadedrod; 12-24-2012, 08:06 AM.


        • #5
          Thanks for the tips guy's. I should sort of clarify a few things, rray you are correct in having the grounds together. I blame it on my limited knowledge of the design app, but it will be a more unified mass of ground not traces of grounds in the final product. Board size will be 4.5x3.25 inches. This is the bottom board of a 2 board set. The top board will attach on to the bottom and will include the fuses/resistors/caps/led's as needed. I am working on the top board now. SNO


          • #6
            I was a PCB designer man in my last job !
            What do you need to do exactly ?


            • #7
              First thing i see into your pcb that you use wires the GROUND and not a shape GROUND and that is a very bad thing !!!!
              Second thing would be to add capacitors between the 5V and the ground for the ODB and PHIDGET chips (47nF/16v and perhaps a 1uf/16v)!!!
              Last edited by pierrotm777; 12-31-2012, 06:40 AM.


              • #8
                SNO; Take a look here at samples for how to design a proper input circuit for the phidget chip:
                It might be wise as stated above to include some kind of design that will allow for some abuse by the user. A mosfet/transistor or a fully isolated input is to be preferred.
                Failure is not an option...
                __________________________________________________ ______________________________
                The only full multizone / multiscreen cross platform open source Front End -> OpenMobile


                • #9
                  Thanks for all the suggestions. I realized my limitations and had a pro finish it off. It's now 4 layer with good planes in the middle. Everything is working perfectly on the board but a couple of small mods need to be done on the next version (diode holes too small, 1 analog input not inline with rest) as well as the 433mhz circuit will be replaced with something alittle more user friendly. It also now has a built-in self powered 4 port hub based on the gl850g chip.
                  Click image for larger version

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                  data from simulator reporting nicely
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                  • #10
                    Very better with ground shape no ?


                    • #11
                      What all do you have working in there Sno? GPS, OBDII, TPMS, and an 8-8-8 Phidget?


                      • #12
                        Right now the current board has scantool's micro obd200, phidgets 8-8-8, 4 pin connector on bottom right is for GPS and a 433mhz receiver. The receiver is for something different from TPMS and I thought it might do 2 things in one but will not happen that way. Also a powered 4 port hub. I am on version 1.3 being designed now with the circuit for the TPMS sold on the mp3 store in place of the wicked device's 433mhz board. Also will be adding a board on top (optional) that will have another 4 port hub with 2 Parking distance circuits (same as the kit designed by robby) and a usb port for camera/printer/scanner/whatever. The gps port will be the uplink port for the addon board and the addon board will have the new GPS port on it. The goal is to get as many of the seperate components used into 1 box with 1 usb cable out, powered by obd2 port. So far so good as it's all working as is. SNO


                        • #13
                          Small update here and it sure has changed from version 1.0 this is version 1.3 and currently gone to PCB fab house should have in a week or so. Next level is being designed now and should be finished by tomorrow. Hopefully I will be assembling and testing both boards next weekend. SNO
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                          • #14
                            Nice progress! I think I might be up for one of these when available, or offered, as I would like to put a carputer in my Ranger next.


                            • #15
                              These are the final design's for the add-on boards. They are made to be stacked on top of each other depending on the option's needed. One board has 2 Parking Distance systems based on the kit from robby either wired or wireless as well as a usb port for camera. The other board is more for the trucking industry that use reefer's. Most use XBee for the communication between the reefer and driver controls and also another TPMS to get the 10 tires on a rig and another usb port... they never have enough it seems.
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