Dirt Rally is a great game, even while it is early access. If you are playing Dirt Rally, then you will want to have a handbrake. Buttons on the wheel don’t work very well in my opinion, they’re hard to press while you’re turning the wheel trying to initiate a slide.
So, I built a handbrake (and sequential shifter) to attach to my rig. I was using a G27 wheel initially, but I’ve since moved to an OSW direct drive. The e-brake and sequential shifter are connected to my G27 shifter at the moment, but I’m planning on selling the whole G27 setup in the near future. The handbrake and shifter work by activating simple momentary switches, which can be soldered into the buttons on any controller you are using. When the G27 is gone, I’ll wire the e-brake and sequential shifter through a MCP23s17 chip connected to the Disco board in my direct drive servo steering wheel. Here’s the shifter sitting alongside my new OSW direct drive.
I used two sealed cartridge bearings for the main pivot in each lever to make it smooth and solid, and I shaped some nice hardwood for the levers themselves. The handbrake is the long lever, and it has a single tactile switch which the bottom of the lever pushes into. The stumpy sequential shifter has two tactile switches mounted just above and below the pivot point for the lever to push into. Having a separate sequential shifter means I can use it to replace paddle shifters with my OpenSimWheel direct drive wheel.
Instead of using coil springs, I’m using EVA foam which I cut from the midsole of an old pair of good quality running shoes. The high quality EVA foam gives it a nice feel, with the right amount of spring and a damped quality that you don’t get with a coil spring (unless you have a damper). I cut squares of foam from the shoe midsole, and drilled a 6mm hole so that I could mount them on a long bolt, and then used a sanding disc on my angle grinder to carefully shape them into a round shape. I’m really happy with how it turned out, I’ve used it a lot and it feels great. I had build a load cell setup for the handbrake, but when I thought about I only want the handbrake on or off for rally. Rally car e-brakes are hydraulic so that they work on/off, you want to definitely lock the rear wheels rather than just slow the car down.
Chillicoke has a great guide on how to disassemble your G27/G25 shifter so that you can wire in a handbrake. Here’s the link.
In comparison to the chillicoke wiring method, there is actually a simpler location for soldering the wires onto your G27 shifter circuit, on the same side of the circuit as shown below. This means you don’t have to unscrew the button panel circuit board and solder to both sides of it. Connect your handbrake switch to these wires. Note the black wire connected to the pad on the left side of C45 (just above the C), which means you don’t need to remove this board and have all the buttons fall onto your workbench. If you want to add a sequential shifter as I did, you can solder two more wires to another couple of buttons – such as R92 and R93 below (and share the wire that goes to the ground connection at C45).