Creating a Open-Source Horse Riding Simulator

Having worked out that I need to add cheek pressure sensors to detect open reins, and that the motion of the head when asking for the horse to turn the head affects the felt pressure on the reins, I am now turning to allowing the head rotate in a more robust manner.  At the same time, I want to make a detached head setup, so that I can easily test the reins interaction from on the ground, without having to mount the "horse". The first step was to think about what I was going to do for the hinge.  So I went out to CBC Bearings at Regency Park and had a chat to the nice folks there, complete with wooden horse head on their counter.  They were very helpful, and we settled on using some nice heavy-duty bearings that take a 20mm steel shaft, to make sure that the weight and forces of the heavy horse head moving are easily accommodated without risk of self-damage etc. The steel shaft I purchased from METALCORP on Grand Junction Road, who were also really helpful.  It turns...

While my goal is to build a complete open-source horse riding simulator, this doesn't mean that I have to wait until I have everything working before I have anything.   Based on conversations with my friendly equestrian experts, I believe that there is potential value in a simple reins pressure trainer, that helps new riders learn to provide smooth and appropriate pressure to the horse's mouth through the reins, as well as be able to practice various activities and techniques with the reins. This is an attractive mile-stone, because it doesn't require any movement of the machine, and I already have the mouth sensors more or less working. A few other pieces fell into place for this today, while I was talking with some colleagues: First, for making a horse head, it's quite likely I can just use those latex costume horse head masks that can be bought quite cheaply as the basis for the exterior, and build a simple structure to hold it.  They already have a hollow mouth, so...

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...