Creating a Open-Source Horse Riding Simulator

Before we get onto the topic at hand, following on from the previous post, a few more thoughts on how the pressure can be measured for the mechanical horse: 1. Measure the deflection of the horse body as an alternative method of measuring the pressure, e.g., using ultrasonic range measurements or LIDAR to map the deformation of the body to determine the location and magnitude of applied pressure. 2. Use a sock or similar pre-made (or partially pre-made) container/sleeve into which the sensor(s) can be inserted for safety/holding together and/or ease of attachment. 3. Use a single resistor in-line with the sensor, to increase the range of measurement.  4. Switch between different values of in-line resistor to improve the sensitivity at different pressure ranges.  This is because the sensor is effectively being used as a voltage dividor made of the sensor and another resistor. The greatest change in voltage occurs when the other resistor is of similar resistance to the sensor. I...

One of the challenges in an open-source project compared with a commercial approach, is that you don't have budget for lawyers to defend against (often frivolous) patent claims.  However, this can be more than offset by using a basic knowledge of patent law. Specifically, if you talk publically about something, no one can go and patent that, or anything that can be obviously inferred from that in any jursidiction thereafter. This is because the public discussion forms part of the "prior art" once it is made public, e.g., by being described in this blog post.  Unlike when you want to file a patent, this disclosure doesn't even need to be "reduced to practice".  There are a lot of names for this approach, but let's just call it Patent Spoiling. The idea is to make sure that you have plenty of freedom of movement in innovation, rather than have someone come and patent all the way around you, so that you can't change or improve anything. So the purpose ...

In a recent post, I described the work so far on making low-cost pressure sensors.  One of the key components in that was a MAX406 Operational Amplifier (Op-Amp) chip to handle the high resistance of the sensors.  However, when I went to design a PCB around this, I discovered to my extreme inconvenience that the IC is actually obsolete, and there is just some dregs of stock around.  So I need an alternative. While thinking about alternatives to the MAX406, it occurred to me that the impedance of my sensors might not be too high for the Arduino's analog to digital converters (ADCs).  This would not only save the cost of the op-amp chip, but would save me having to find a suitable one :) The ADCs basically need a voltage that varies with the resistance of the sensor.  I could just connect one pin of the sensor to the ADC, and the other pin of the sensor to either ground or +3.3V, but it would be relying on the current leakage of the ADC to provide it with a refere...

To detect rider aids we need pressure sensors, for example to detect leg position and pressure, as well as the weight distribution of the rider in the saddle. I first looked at this article that suggests that conductive fabric and static bags can be used to detect pressure.  The paper claims that the resistance of static bags is in the 10K to 1M Ohm range.  However, elsewhere I see that the resistance is actually in the 1G - 10G Ohm range, making it impractical. I simply can't get my multi-meter to register any resistance, even when pressing probes hard into the static bags. This is annoying, because the idea is simple and great, and can be further simplified and cost-reduced by using conductive electric fence ribbon in place of the expensive conductive fabric layers.  Some brands of electric fence ribbon even have multiple metal threads that don't touch each other along the length of the ribbon, which would allow a single length of ribbon to sense pressure a different r...