Because we don't want the precision of the sensors or the efficiency of the steering part of the robot influanced by a decreasing voltage from the batteries, a constant voltage to feed the sensors and the microcontroller is desired.
In order to obtain this we have several options.
Steering part with 3.3V obtained with a voltage regulator:
The voltage we intended to work with was 5V coming from four AA batteries. The main problem is that when the batteries approach their expiration, the voltage will sink under 5V and the risk of deranging the sensors and the matching program is probable. cover iphone 6 plus custodia That's why it's designated to regulate the voltage to a lower voltage, 3.3V, and adapt the steering part and the sensors to this voltage in order not to be exposed to that kind of problems again.
Up to now we always tested with a voltage of 5V. samsung custodia outlet Ofcourse multiple changes are to be made when the voltage over the sensors and the microcontroller is changed. For instance the resistance to go with the sensors will be changed to get the optimum result.
The resistors replacing 10kΩ resistors, placed together with the photodiodes, will now hold a value of 5.6 kΩ. cover iphone custodia outlet With this resistance again clear differences will be measured.
Also the resistance to go with the LEDs of the sensors will change because now a lower voltage is available. custodia huawei shop Because those LEDs have a forward voltage from 3.2V to 4V no resistor is needed.
The IR emitter and the green LED have together a forward voltage of ± 3.3V. custodia samsung s7 edge Also here the resister can be left out.
Fortunately all the features are working when 3.3V is used, this makes a voltage of 3.3V for the steering of our robot a reasonable solution.
Steering part with 5V coming from 9V and a voltage regulator:
By using a battery holder fit for six AA batteries a voltage of 9 Volt is obtained. iphone cover original The voltage will never sink under 5V. cover iphone 8 plus custodia outlet So by using a voltage regulator the voltage can be set on a constant 5V voltage.
An inconvenient disadavantage is that a big battery holder is harder to install on our rather small robot.
On the other hand earlier tests showed that all features work perfectly with 5V.
Steering part with 5V coming from 6V and a DC-to-DC converter:
Some DC-to-DC converters, like the SEPIC or the buck-boost converter, can convert a voltage up or down. These converters are used to convert voltages to a constant voltage, like the voltage coming from a battery which can be set on a constant voltage even though the input voltage drops beneath the wanted output.
This means using this kind of converters it would be possible to work with a constant 5V voltage when using four AA batteries (6V) without the functionality of the robot endangered near the expiration point of the batteries.
These converters are quite expensive and are not really necessary when we're going with one of the previous options.
Because the robot we are constructing ought to be small, we want to use a small battery holder. We opt for the simplest and the most inexpensive posibility.