Sourcing Parts

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Encoder

I used an OMRON Rotary Encoder Incremental E6B2-CWZ6C 2000P/R found on ebay for $40 delivered from China. I noticed these seem to range in price from under $40 to $200+ and also the encoder ppr count varied so look for a good deal. These encoders also have an index output which is ideal for the MMos controller software to detect when the wheel is centered.

You don't have to use the above encoder. The requirements are basically for a 2000ppr quadrature encoder that you can somehow mount to the stepper motor (accurately). Yes it has to be 2000ppr (8000cpr) to use the current Sim Wheel Stepper Motor Controller, this may change in future but for now is mandatory. 2000ppr or pulses per revolution means that each of the encoder signals output 2000 pulses in a single revolution. Using quadrature encoding it is then possible to detect each rising and falling edge of these pulses on both signals giving a resolution of 8000cpr or counts per revolution.

Encoder Mount

Stepper Motor

I bought the Nema 34 13Nm Stepper Motor from australian ebay store au.stepperonline but they shouldn't be too difficult to find elsewhere. For example http://www.omc-stepperonline.com/ The points to look out for are Nema 34 size, 13Nm holding torque, 5A per phase, although this isn't even that important for example you could use an 8Nm motor for less torque or a Nema 23 size etc. just be aware if they are reated with a lower phase current the controller could burn out the windings. You must be able to access the shaft from the back of the motor (to mount the encoder) and it really helps if the shaft has a center tap because you need to drill the back of the shaft and it must be accurate.

Sim Wheel Stepper Motor Controller

Purchased from this site here: Purchase

Power Supply

A single 24V power supply is required for the stepper sim wheel. A 10A switch mode power supply or greater is recommended. The ones sold on ebay as supplies for LED strip lighting work well.

STM32 Discovery

The Discovery board is the one that holds the PC FFB Wheel Controller interface firmware specifically that developed by MMos. This is the firmware used in most OSW (Open Sim Wheel) projects. OSW and MMos are arguably the projects that kicked off the DIY direct drive sim wheel era based around Servo Motors.

The Discovery board is a "development board" that was used by MMos to develop the pc ffb wheel controller. This board is needed to interface the stepper sim wheel motor driver to the computer. The board model I used is a STM32F4DISCOVERY (pictured below).

It seems to have been replaced by an upgraded version the STMF407G-DISC1. Some sources include:

More recently I have noticed others using the STM32F407CORE which I understand has a different layout but operates equally well - however I have not tried this board myself.

Steering Wheel

Steering wheels come in many styles and range in price considerably depending on quality. Choose one that suits your own needs. The cheapest I have found in Australia is $40. A 320mm diameter is a good size for a sim wheel. Most come with standard 6 point mounting on a 70mm PCD (Pitch Circle Diameter - the diameter the bolt centers lie. Sometimes called BCD - Bolt Center Diameter). You will need an adaptor to mount the wheel to the motor shaft.

Steering Wheel to Motor Shaft Adaptor

Motor Mount

Can easily be made out of wood or steel depending on tools available. They are also available for purchase by motor suppliers or even specifically designed as adjustable sim wheel mounts from some of the OSW part suppliers.

Optional Parts

Connectors

I find the following round metal connectors to be excellent for the connection between motor to case and encoder to case. Searching for metal aviation connectors panel mount on ebay should find plenty of suppliers. They are of good quality for a relatively low cost. You need a 4-pin for the motor and a 5-pin for the encoder.

They are also available from Jaycar part PP2017, PS2018, PP2010, PS2012 and other suppliers.

If you use these connectors be very careful that the wire/solder joints don't touch and short to the metal case - it will likely damage the motor control board!

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