The DIYPNP has two proto areas on the main board, and some versions have additional proto space on the adapter board. The holes in these proto areas are interconnected to make building circuits easier; connected holes are indicated by white dots in between the holes. These proto areas give you room to build model specific circuits your application may need, or just to get creative and try out new circuits. Here, we’ll show you a couple examples of circuits you may find useful on certain cars. It’s also possible to make circuits in the proto area for applications such as nitrous control, EGT logging, speed sensor inputs – the possibilities are only limited by the code and your imagination.
This picture shows the connections on the proto area on the main board in blue-green lines. The N42 board has similar, extra proto areas on it for even more circuitry if you should happen to need it. Here are two examples of circuits that some users might find handy. Click on the images for a larger view.
First circuit is a 3 wire IAC driver circuit. This one uses a pair of TIP120s to drive the opening and closing coils of a 3 wire idle air control valve. While the B55 board has this built in, some cars that use the N76 board (particularly Toyota and Subaru products) also use versions of the 3 wire IAC valve. This circuit takes the IAC signal and splits it into two opposite signals. The IAC_Open output is grounded when the input is grounded, and the IAC_Close output is grounded when the input is not grounded.
The above circuit is one we designed for controlling a VTEC solenoid. While normal relay control circuits work by switching the ground to a relay, Honda used their ECU to supply 12 volt power to the VTEC solenoid. This circuit uses a TIP125 PNP Darlington transistor to power a solenoid with a current limit of up to 5 amps. The part marked “To MS CPU” can be connected to any of the logic level on/off outputs: PT6, PT7, or PA0.
This alternate VTEC control circuit uses WLED or ALED as an input. Which one to use depends on what outputs you have available. It could also use the IAC output as an input, but normally you would be using that for idle control.