gbulmer
commented
4 years ago If the values of the emitter and phototransistor become 'generic', and specific part numbers are in separate build information, then their appropriate resistor values could be treated in exactly the same way. Ie. the values of the appropriate emitter and phototransistor resistors could also be removed from schematic and PCB CAD, and maintained in the sensor board's separate build information.
Assuming the builder can cope with separate sensor board build information for alternative emitters and phototransistors, then they likely can also cope with different resistor values.
IMHO, removing specific emitter and phototransistor resistor values from the sensor board schematic and PCB, and making them 'generic' and hence resolved in separate build information would be helpful:
- It would explicitly relate resistor value to emitter and resistor value to phototransistor which could help any explanation of the relationship between these parts.
- It reduces confusion (which would need to be understood) when alternative emitter and phototransistor pairs are used because they would not be on the PCB or schematic. All the related part values would need to be extracted from the same separate sensor board emitter and phototransistor build information.
- Separate sensor board build information might eventually contain explanations of how the resistor values were derived, helping builders who might want to try alternative components.
This doesn't prevent their being multiple versions of the sensor boards schematic and PCB CAD. One set might be generic, and others (maybe only the PCB?) with specific values for everything to help builders who require the most straightforward build information.
The sensor boards support the use of many different LED emitters, phototransistors and switching device. It is expected that this will be a differentialting factor between robots.
The board schematics and silk screens for these parts should be changed from specific devices to generic device names with separate build information giving advice on possible devices. The reference build will determine the value of associated resistors and these values will be included in the schematic and on the silk screen. Builders using devices other than the reference build will need to substitute different value resistors where necessary.