12 bit serial data transmitted and received. 

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... order to design a good horse jump the mechanics of a horse jumping needed to be considered. When the horse is approaching an obstacle it needs to see, appraise and accept the jump. Therefore the jump needs to be simple and clearly outlined. As it is seen in Figure 4 , during takeoff and landing the horses forelimbs have potential to strike the top of the jump, therefore a collapsible jump pole is needed that will fall when hit with a horizontal force. Key jumping factors in horse training are: - The horse should be able to learn from its mistakes - The horse should be confident When the rider has to stop and alter the jump, the horse drops its momentum, with jump height alterations being made while riding, the horses momentum is not lost resulting in much more effective horse training. Horse jumps are made up of three main parts: Stands, Cups and Poles [4]. The stands are available in many different types of materials such as wood, aluminium and plastic. Figure 5 shows an example of a stand. The main design requirements in a stand are: - Can be easily transported by hand - Will not fall over in the weather - Have no sharp edges - Can withstand the weight of the poles The cups main purpose is to mount onto the stands and provide support for the poles. They are mostly made from various metals and plastics. Figure 6 shows the cups. Their design requirements are: - Can lock into place at desired height - Can hold poles stable but will release when knocked - Will fail at 135 kg of pressure (if a horse was to fall onto the poles) The RF link must be compliant with the Federal Com- munications Commission (FCC) [5] rules under Section 47, Chapter 1, Part 15, entitled “Radio Frequency De- vices”. This section lays out the rules and regulations involved with operating a radio controlled device without a license. The device must not cause harmful interference and it must accept any interference that may cause unde- sired operation. Part 15, 23 specifies that “home-built” devices need only be compliant with FCC regulations to the best of the builder’s extent, but does not have to comply otherwise. The horse jump must ideally have no sharp edges in- case the rider or horse shall collide with the stand or any other component. The poles must also collapse when a reasonable pressure is applied to prevent further injury to the horse. The key design constraints considered were: - Height (a variable jump pole from 50 cm to 1 m) - Lightweight (able to place in yard by one person) - Durable (can tolerate outdoors, curious horses and shock loads from jump poles being knocked around or undesirable collisions) - Can withstand the weight of the poles - Poles are held stable but release when knocked - Stand will comfortably hold load from pole of 100 N (10 Kg) Additional design parameters were: - Simple and affordable due to a low prototype budget - Locking mechanism to hold jump pole in place - Ease of manufacture With these parameters in mind 3 key concepts were developed. Figure 7 shows the first design concept. This design seems very ideal as both sides will remain horizontal. It was decided to disregard this concept due the larger number of mechanical components and potential elasticity in load-bearing components. Also with such a large frame, moving it around will be difficult. Also due to its sturdiness, if the horse or rider were to collide with the sides of the frame, injuries could be caused. The second concept design proposed is shown in Figure 8 . This concept proposed a large belt to rotate around the stand, Poles could then be attached to the rotating belt where desired. The major challenge with this design is that a motor brake needed to be incorporated into the design which results very inefficient operation. Also the large belt seemed hazardous and after consulting expe- rienced horse jumpers, more noticeable moving objects will be likely to spook their horse resulting in ineffective jumping. Figure 9 shows concept design 3. The third and final design is ideal. It conforms to all constraints and parameters proposed initially. The major advantage is that the screw style lift prevents the need for a motor brake. The next step of the design process was to simulate major points of fatigue while ensuring the prototype can be easily constructed with readily available materials. To do this a stress test using CosmosWorkTM [6] was conducted. Detail in [6] indicates major points of stress are expe- rienced at the nut where the cup is connected to the ver- tical shaft. An extra block was inserted to improve axial stress on the threaded rod as shown in Figure 10 . With the added block, the factor of safety was im- proved from 3.2 to 4.5. Both of these results are acceptable but because the threaded rod used is not purpose built, the threads are susceptible to fraying. Therefore the highest attainable factor of safety was sought after. With a finalized design, workshop staff proceeded to construct the jump. Small additional changes, such as a one piece aluminum casing, were made to improve ease of manufacture. The desired lifting speed of 1 cm/sec was aimed for. To achieve this, appropriate gearing and motor power needed to be considered [see Figure 11 ]. By using a gear ratio of 1:5, incline angle of 0.1 degrees and RPM of 300. The Torque needed at the motor was 0.2 Nm . From these results the desired power needed from the motor was calculated as 40 W. A cost effective PMDC gear motor [7] was selected and then tested in the lab for its characteristics. It produced easily 100 W at 24 VDC drawing 1.6 A at no load. With a simulated load it was noticed that there was almost no change in RPM (due to the gearing) and the motor was drawing 2.6 A. From these results the design constraints for the motor control module were set to be able to satisfy 4 A load at 24 VDC. According to a survey conducted to pony club attendants, the desired control of the horse jump was Up and Down control via portable remote control. Infra Red [8] was not ideal due to the rider would be uncomfortably pointing the remote constantly, Other means such as WiFi [9] and Bluetooth [10] were over excessive therefore RF control was ideal. The RF link consists of three modules; Transmitter, Receiver and Logic Control. The Transmitter design constraints were: - Transmit at least 2 channels of data - Powered by replaceable batteries - Small enough to meet expected aesthetics of a remote control Figure 12 shows the schematic of the transmitter which was developed in Altium DesignerTM [11]. The transmitter module was purchased from JayCar Electronics [12]. When a button is pressed the encoder is activated, producing serial data to be sent to the transmitter module for transmission. A specific 8 bit data ad- dress can be set to minimize any interference caused by any surrounding RF devices. This circuit is capable of transmitting another 2 channels of data. These channels can be used for upgrading the horse jump, such as re- motely activating a pickup sequence when a pole is knocked off. The Receiver design constraints were: - Receive at least 2 channels of data - Powered by 5 V Regulated supply - Produce logical outputs to be processed by the Logic Control module The schematic for the receiver which was developed in Altium DesignerTM is shown in Figure 13 . The receiver module was purchased from JayCar Electronics. When a data signal is received that corres- pond to the Data Address, The decoder then demodulates the signal and produces a Logic output to be processed by the Logic control module. The Logic Control design constraints were: - Process logic signals from receiver - Process logic signals from limit switches (two switches at each maximums of travel) - Powered by 5 V Regulated supply - Produce Desired outputs for Motor Control module A NAND gate equivalent schematic was formed in Altium DesignerTM as shown in Figure 14. The transmitter and receiver were tested running on bench supply. Data was successfully transmitted between modules. Figure 15 shows a 12 bit serial data being transmitted and received. The outputs of the receiver were measured using an oscilloscope to ensure data can be processed by the Logic Control module. The Motor Control design constraints were: - Process logic signals from Logic Control - Produces 5 V Regulated supply to power other modules and itself - Have forward and reverse motor control - Produce 24 V at 4 A for ...