In today’s world of over-the-air firmware upgrades in everything from cars to phones to refrigerators, it’s common for manufacturers of various things to lock out features in software and force you to pay for the upgrades. Even if the hardware is the same across all the models, you can still be on the hook if you want to unlock anything extra. And, it seems as though Suzuki might be following this trend as well, as [Sebastian] found out when he opened up his 2011 Vstrom motorcycle.

The main feature that was lacking on this bike was a gear indicator. Even though all the hardware was available in the gearbox, and the ECU was able to know the current gear in use, there was no indicator on the gauge cluster. By using an Arduino paired with an OBD reading tool (even motorcycles make use of OBD these days), [Sebastian] was able to wire an LED ring into the gauge cluster to show the current gear while he’s riding.

The build is very professionally done and is so well blended into the gauge cluster that even we had a hard time spotting it at first. While this feature might require some additional lighting on the gauge cluster for Suzuki to be able to offer this feature, we have seen other “missing” features in devices that could be unlocked with a laughably small amount of effort.

It is getting difficult to find a desktop or laptop computer with only a single CPU. Even a typical ARM-based computer now probably has multiple cores. Of course, there’s nothing to stop you from using multiple microcontrollers — like the Arduino — together. To make the process neater, [Dimitris Platis] put together Moltoduino, essentially an Arduino on a shield made to plug into another Arduino. And, yes, they will stack. You can see a video about the open source boards, below.

The key is how the board brings the pins out to connections that are easy to jumper between boards. There are several obvious use cases, but one that [Dimitris] is particularly interested in is hardware-in-the-loop testing. The idea is that you can use a simulated I/O device in one computer to exchange fake data with the software under test.

For example, you might be working on a sous vide cooker that reads a temperature and controls a heater. A second computer could stand in for the temperature sensor and heater. You could log outputs and also control the inputs. This is really nice when you want to set up repeatable test cases.

Of course, you don’t have to stack the boards to make that work. In fact, you don’t have to use another Arduino. A PC or some other controller could be the surrogate test device. But having it all in a stack is handy. There are several examples of doing testing using simulated hardware on the project’s GitHub page. The test subjects are a robot car and an ultrasonic device.

One neat feature is that each board has a switch to enable the master Arduino to ISP program it. So while you might not need to stack boards to use any of the proposed techniques, it does make for a nice and compact package.

Usually, when we see a cluster it uses Raspberry Pis. Or, sometimes, PCs.