Changes for page Sensor Module
Last modified by Heimir Thordarson on 2026/07/05 12:56
From version 60.1
edited by Heimir Thordarson
on 2026/02/18 12:06
on 2026/02/18 12:06
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To version 57.3
edited by Heimir Thordarson
on 2026/02/09 19:55
on 2026/02/09 19:55
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... ... @@ -24,7 +24,7 @@ 24 24 25 25 The Sensor module is designed to measure any extra analog signals rear of the firewall. For AR26, the module is designed to measure two suspension displacement sensors, two oil temperature, four water pressure, four water temperature, and one air temperature sensor. All of the measurements are then transmitted to a CAN network, which there are two of. 26 26 27 -= D esign=27 += Wiring Diagram = 28 28 29 29 In the following section, how the sensor module is connected will be covered. The connector for the sensor module is a [[High-Density d'sub-44>>https://www.te.com/en/product-2311770-1.html]] which is directly solderen onto the circuit board. The plug needed for this system is the [[204517-3>>doc:Sandbox.TestPage3]], which uses crimps instead of solder cups which is common for the dsub connectors 30 30 ... ... @@ -86,10 +86,10 @@ 86 86 87 87 Where: 88 88 89 -* {{mathjax}}\(R_f\){{/mathjax}}= The upper resistor in the voltage divider which stays fixed, which in this case is 4.7k {{mathjax}}\(\Omega\){{/mathjax}} 90 -* {{mathjax}}\(V_{out}\){{/mathjax}}= The voltage over the thermistor, and the voltage that the microcontroller will measure. 91 -* {{mathjax}}\(V_{in}\){{/mathjax}}= The supply voltage of the voltage divider, which in this case is a constant 3.3 {{mathjax}}\(V\){{/mathjax}} 92 -* {{mathjax}}\(R_T\){{/mathjax}}= Resistance of the thermistor 89 +* {{mathjax}}\(R_f\){{/mathjax}} = The upper resistor in the voltage divider which stays fixed, which in this case is 4.7k {{mathjax}}\(\Omega\){{/mathjax}} 90 +* {{mathjax}}\(V_{out}\){{/mathjax}} = The voltage over the thermistor, and the voltage that the microcontroller will measure. 91 +* {{mathjax}}\(V_{in}\){{/mathjax}} = The supply voltage of the voltage divider, which in this case is a constant 3.3 {{mathjax}}\(V\){{/mathjax}} 92 +* {{mathjax}}\(R_T\){{/mathjax}} = Resistance of the thermistor 93 93 94 94 Knowing this, the resistance of the thermistor can be added into the following equation. This will determine the temperature of the thermistor based on the known resistance and the beta value of the thermistor. 95 95 ... ... @@ -104,10 +104,10 @@ 104 104 105 105 where: 106 106 107 -* {{mathjax}}\(\beta\){{/mathjax}}= material constant that defines the steepness of its resistance-temperature curve between two temperature points, usually 25/85 degrees celsius. In this case it is 3694 //**K.**// 108 -* {{mathjax}}\(T_0\){{/mathjax}}= The test temperature at which the thermistor is 10k {{mathjax}}\(\Omega\){{/mathjax}}, which in this case is 25 degrees celsius. 109 -* {{mathjax}}\(R_0\){{/mathjax}}= The resistance of the thermistor when it is 25 degrees celsius. 110 -* {{mathjax}}\(R_T\){{/mathjax}}= The live resistance of the thermistor.107 +* {{mathjax}}\(\beta\){{/mathjax}} = material constant that defines the steepness of its resistance-temperature curve between two temperature points, usually 25/85 degrees celsius. In this case it is 3694 //**K.**// 108 +* {{mathjax}}\(T_0\){{/mathjax}} = The test temperature at which the thermistor is 10k {{mathjax}}\(\Omega\){{/mathjax}}, which in this case is 25 degrees celsius. 109 +* {{mathjax}}\(R_0\){{/mathjax}} = The resistance of the thermistor when it is 25 degrees celsius. 110 +* {{mathjax}}\(R_T\){{/mathjax}} = The current resistance of the thermistor. 111 111 112 112 === Filtering === 113 113 ... ... @@ -124,9 +124,9 @@ 124 124 125 125 Where: 126 126 127 -* {{mathjax}}\(F_c\){{/mathjax}}= Cut-off frequency of the filter. Any noise with a frequency above this will be filtered out. 128 -* {{mathjax}}\(R\){{/mathjax}}= Resistance of the resistor in low-pass filter. 129 -* {{mathjax}}\(C\){{/mathjax}}= Capacitance of the capacitor in the low-pass filter. 127 +* {{mathjax}}\(F_c\){{/mathjax}} = Cut-off frequency of the filter. Any noise with a frequency above this will be filtered out. 128 +* {{mathjax}}\(R\){{/mathjax}} = Resistance of the resistor in low-pass filter. 129 +* {{mathjax}}\(C\){{/mathjax}} = Capacitance of the capacitor in the low-pass filter. 130 130 131 131 Using a resistor with 1k {{mathjax}}\(\Omega\){{/mathjax}} and a capacitor with 100 **nF **in capacitance, the cut-off frequency will be 1592 **Hz.** 132 132 ... ... @@ -153,9 +153,9 @@ 153 153 154 154 where: 155 155 156 -* {{mathjax}}\(x\){{/mathjax}} = The mechanical placement excluding the dead length (178mm). 157 -* {{mathjax}}\(V_s\){{/mathjax}}= The supply voltage of the linear potentiometer, in this case it is 3.3 {{mathjax}}\(V\){{/mathjax}}. 158 -* {{mathjax}}\(V_{out}\){{/mathjax}} = The output voltage of the linear potentiometer. ranging from 0.033{{mathjax}}\(V\){{/mathjax}} to 3.267{{mathjax}}\(V\){{/mathjax}}. 156 +* {{mathjax}}\(x\){{/mathjax}} = The mechanical placement excluding the dead length (178mm). 157 +* {{mathjax}}\(V_s\){{/mathjax}} = The supply voltage of the linear potentiometer, in this case it is 3.3 {{mathjax}}\(V\){{/mathjax}}. 158 +* {{mathjax}}\(V_{out}\){{/mathjax}} = The output voltage of the linear potentiometer. ranging from 0.033{{mathjax}}\(V\){{/mathjax}} to 3.267{{mathjax}}\(V\){{/mathjax}}. 159 159 160 160 === Filtering === 161 161 ... ... @@ -165,7 +165,7 @@ 165 165 166 166 The gearbox Temperature Sensor for AR26 will be the [[GAG10K3976B1>>https://www.te.com/en/product-GAG10K3976B1.html]], a NTC temperature probe which will be installed into a generic M5 bolt which is mounted on the upright in the wheel assembly. The thermistor will be connected in a voltage divider configuration where the thermistor is in the lower position so that the voltage lowers when the temperature increases. 167 167 168 -[[image:Oil_Temp_schematic.png||height="2 08" width="486"]]168 +[[image:Oil_Temp_schematic.png||height="271" width="632"]] 169 169 170 170 Knowing the beta constant of the thermistor, the equation for the temperature based on the voltage measured by the ADC inside microcontroller can be derived. 171 171 ... ... @@ -180,10 +180,10 @@ 180 180 181 181 Where: 182 182 183 -* {{mathjax}}\(R_f\){{/mathjax}}= The upper resistor in the voltage divider which stays fixed, which in this case is 1k {{mathjax}}\(\Omega\){{/mathjax}} 184 -* {{mathjax}}\(V_{out}\){{/mathjax}}= The voltage over the thermistor, and the voltage that the microcontroller will measure. 185 -* {{mathjax}}\(V_{in}\){{/mathjax}}= The supply voltage of the voltage divider, which in this case is a constant 3.3 {{mathjax}}\(V\){{/mathjax}} 186 -* {{mathjax}}\(R_T\){{/mathjax}}= Resistance of the thermistor 183 +* {{mathjax}}\(R_f\){{/mathjax}} = The upper resistor in the voltage divider which stays fixed, which in this case is 1k {{mathjax}}\(\Omega\){{/mathjax}} 184 +* {{mathjax}}\(V_{out}\){{/mathjax}} = The voltage over the thermistor, and the voltage that the microcontroller will measure. 185 +* {{mathjax}}\(V_{in}\){{/mathjax}} = The supply voltage of the voltage divider, which in this case is a constant 3.3 {{mathjax}}\(V\){{/mathjax}} 186 +* {{mathjax}}\(R_T\){{/mathjax}} = Resistance of the thermistor 187 187 188 188 Knowing this, the resistance of the thermistor can be added into the following equation. This will determine the temperature of the thermistor based on the known resistance and the beta value of the thermistor. 189 189 ... ... @@ -198,21 +198,7 @@ 198 198 199 199 where: 200 200 201 -* {{mathjax}}\(\beta\){{/mathjax}}= material constant that defines the steepness of its resistance-temperature curve between two temperature points, usually 25/85 degrees celsius. In this case it is 3976 //**K.**// 202 -* {{mathjax}}\(T_0\){{/mathjax}}= The test temperature at which the thermistor is 10k {{mathjax}}\(\Omega\){{/mathjax}}, which in this case is 25 degrees celsius. 203 -* {{mathjax}}\(R_0\){{/mathjax}}= The resistance of the thermistor when it is 25 degrees celsius. 204 -* {{mathjax}}\(R_T\){{/mathjax}}= The live resistance of the thermistor. 205 - 206 -=== Filtering === 207 - 208 -The sensors output latency can be expected to be a lot shorter than the oil temperature sensor as the sensor is just a variable sensor based on placement. The limiting factor for the system which uses this information is the CAN-BUS messages from the inverters which send the information each 6.25 milliseconds. This means that the cut-off frequency cannot be any lower than 160 Hz, which will make the same type of low pass filter from the oil temperature sensor acceptable with a cut-off frequency of 1591 Hz. 209 - 210 -= Bill of Materials = 211 - 212 -== Circuit Board == 213 - 214 -== Wiring Harness == 215 - 216 -== Sensors == 217 - 218 - 201 +* {{mathjax}}\(\beta\){{/mathjax}} = material constant that defines the steepness of its resistance-temperature curve between two temperature points, usually 25/85 degrees celsius. In this case it is 3976 //**K.**// 202 +* {{mathjax}}\(T_0\){{/mathjax}} = The test temperature at which the thermistor is 10k {{mathjax}}\(\Omega\){{/mathjax}}, which in this case is 25 degrees celsius. 203 +* {{mathjax}}\(R_0\){{/mathjax}} = The resistance of the thermistor when it is 25 degrees celsius. 204 +* {{mathjax}}\(R_T\){{/mathjax}} = The live resistance of the thermistor.