The 48mm board for the 52mm gauge is taking shape, A few features has been dropped because of the extremely tight space. There are three buttons on the front panel, they will probably be used for +,- and select. The main board now only have the wideband lambda, voltage output, displays and three buttons. I'm designing it to take an add-on board with additional features like communication RPM input, MAP sensor and the drivers for the boost control.
I finally remembered to measure one of the Autometer 52mm gauges, the housing has 52mm outer diameter just like expected. The bezels outside diameter is 56mm and the bezel extend 11mm from the mounting surface. While I was at it I destroyed a cheap water temp meter from the Swedish company Biltema, I hoped to find the name of the company who makes it for Biltema, but no such luck. But just like I suspected the enclusure is very well suited for our application.
The cup is 48.5mm internally, 51.5 externally, the nylon ring that hold the glass (real glass!) is 46mm internally.
We have discussed building the AfreshTiny in a 52mm gauge enclosure; the rendered 3d drawings look very nice. It looks like the front end will be CNC machined aluminium. The sixteen led’s will be arranged around the perimeter of the face, the led display will probably be in the middle of the face.
I will try to make room for a MAP sensor in the enclosure; a lambda log is almost useless without rpm and load signals. The MAP sensor makes it possible to build a boost control using the same hardware; if we add a second high current driver we will be able to have boost control and wbo2 at the same time. MAP sensor and boost control will probably be an option. It’s not impossible that this will be on a sandwiched board, but I will try to avoid it.
The RPM input makes it easy to implement a sequential shift light. We only need a four additional LED’s to implement that. Flashing ALL 20 LED’s on the meter when it’s time to shift is probably a good idea since we are after the ‘startle effect’.
Most of the buttons will be used for the boost controller. We will have an external boost curve select button. This will only work if the boost curves have been set through with a PC. If the boost curve select button is held the ‘scramble boost’ function is activated. After trying it you will not want to be without it, it can transform an almost undrivable car to a comfortable daily driver. There will also be a + and a – button for adjustments to the boost level or for use as an offset of the active boost curve. A display mode button will be there, this will also be used to enter setup mode if it’s held for 2seconds.
The four buttons will be: + ,- , display/setup and boost curve select.
The Wbo2 will only need a button that switch between AFR and Lambda. The display/setup button will work well for that. A way to initiate free air calibration is also needed, I think that holding all four buttons for five seconds is a good way to do this.
I have been thinking about the standalone wbo2 a bit this morning. While working on the Wbo2 it’s evident that the design is a bit unbalanced, what I mean to say is that the incredible four-channel wbo2 specification deserves to be backed up with additional features.
The current specification has a 16led bar and a three-digit LED display and it’s only possible to present data from one of the sensors on the display. There are also two voltage outputs and a serial output that will be very useful. It’s possible to add an external character LCD where all the sensors can be displayed. There are also two EGT inputs that are only populated on special order because of the price of the chips, it will also be possible to add an internal MAP sensor. With the LCD, EGT and MAP added it’s a very nice logger package but it will be a bit expensive for a standard model. The options to have MAP and external LCD makes it a bit big. To big for the internal LED display to very useful, it would work best used as a hide away unit.
I would really want the unit to be smaller, removing the connector for the external LCD makes a huge difference on the size but the MAP sensor alone does not make much of a difference. Removing the possibility to use a whole bunch of sensors also make a difference because of the removed connector space, a unit like this would also only need seven cables going to it. The serial interface would remain but it’s only a 3.5mm plug. We could step down to a smaller processor for a unit like this and we would probably sell quite a few units and with around 9euro lower cost per unit on the mcu alone it may be worth the time porting to a smaller Mega processor.
If we branch to two entirely different units we would be freer when designing the top end model. If we remove the displays from the hide away box we save tons of board space. Removing the displays also make the size less critical and it allow us to make more connections to the box. Better connectors can also be used.
I came up with something that look very much like the AfreshBoard, however built to be as code compatible with the GenBoard/VerThree as possible. It could feature 4xWbo2 channels, 4-8xEGT’s, RPM input, intake air temp, coolant temp, oil temp and pressure, fuel pressure, manifold air pressure, exhaust back pressure. It would also feature a MMC cardholder to act like a standalone logger. The interface would consist of a few buttons on the separate display unit, the LCD display, the RS232 interface, at least four voltage outputs, PS/2 keyboard interface. This would be a pretty hard unit to design and it will take some time to do it but with the entry-level unit already out there I don’t see that as a problem.
Image test Mini-Dash