arduinoinfraredphotodiode
I'd like to use 50 ir photodiodes.
But, I'm not sure about it because I want it to be read only on one analog pin of an arduino.
My idea is to wire parallel like in this picture.
But, I'm just not sure if all photodiodes will work if I wire like this…
So, is my schematic right or wrong?
If it is OK, what value should I use for the resistors?
Or do I need another component to connect all the photodiodes to one pin on an arduino?
Thanks
Yes.
using RC servo signals
This looks like it will work great with the DIP switches set to "servo" mode. The documentation at that link implies that motor driver accepts 2 independent standard "R/C servo" inputs to drive 2 independent motors, and its output to those motors appears to be compatible with your 12 V 4 A DC motors (I'm assuming you have 2-wire DC motors, rather than 3-wire, 4-wire, or 5-wire motors).
The Arduino Servo library claims it can control 12 independent RC (hobby) servo motors on most Arduino boards, driving them from 12 independent digital output pins.
using analog 0 to 5 V signals
I'm not sure this will work for you with the DIP switches set to "analog" mode. The Arduino analogWrite() library appears to only support controlling 6 independent motors on most Arduino boards. As long as you are fine with independently controlling at most 6 motors per Arduino board, the "generate PWM and filter to get analog" approach looks like it would work just fine, also.
The problem with hobby related solutions is documentation is limited and not spec'd like commercial components or modules.
It is possible that it may work but make a block wiring diagram and consult with the OEM is advised. Mind you I don't know if they have adequate support for your question as these are built in China.
Hobby Services 3002 N. Apollo Dr. Suite 1 Champaign, IL 61822 (217) 398-0007 E-Mail: hobbyservices@hobbico.com Internet Address: www.supertigre.com
It appears that your ultrasonic load is TTL so there is no problem switching 5 at the same time with a BEC, but I wonder if you have considered the effects of crosstalk on firing all at the same time. They indicate a 15deg detection angle but this would depend on the reflection angle of objects you wish to detect. There may be phasing issues with reflection cancellations like having 5 tweeters directed in a room. Reading the response of each echo in parallel with a time interval count won't be a simple textbook result with non-smooth objects with 5 senders.
YOu can test your orthogonal array design with any signal pulse generator and look at the signal on a parallel port logic analyzer or scope to ensure what you are design will work.
Power drive is the least of your concerns from these low power devices. Noise avoidance from conducted and radiated sources will be paramount and design of the transponder array must come first. I would spend some time on testing this part 1st to identify all the electrical, physical, acoustic, EMI, thermal, vibration both conducted and radiated sources of interference and how each affects your SONAR expectations with different objects. Will it be microphonic with vibration or loud pulse noises. How well does it reject other ultrasound sources of noise? Will the TTL Echo output change in pulse width with signal strength or just the delay time.
Will you get echos from the wrong sender due to corner refection effects.
Best Answer
I'm afraid that doing it the simple way simply will not work. Let's say that your diodes are drawing 1 mA each. With 50 in parallel, that will be a total of 50 mA. Assuming a resistor of about 50 ohms, your nominal voltage will be $$V= 5 - iR = 5 - .05\times 50 = 5 - 2.5 = 2.5 \text{ volts} $$ and if a bug blocks all of the light to one diode the current will drop by 1 mA, and the voltage will increase by $$\Delta V = .001\times 50 = 50\text{ millivolts} $$ While this is detectable with an Arduino, it overlooks something important. If the overall illumination level changes by 2%, the current will also change by 1 mA, and the voltage change will be impossible to distinguish from a bug.
What you need to do is to sample each diode in series, and fast enough not to miss a bug, and at your apparent level of knowledge I haven't the faintest idea how to do that.
Sorry.