CrisisTech Blog

Sometimes you need to check a remote control but you have no time or instruments to check it.
The most common failures are damaged buttons or a dead crystal oscillator.
These remote devices are very sensitive, f.e. common human habits such as drinks and food are not healthy for buttons or
an accidental short flight on the floor is not a good idea either..lol.
There are several ways to test a remote control but if you need a cheap & easy probe i have a solution for you.
BPW41N is a high speed and high sensitive PIN photodiode in a flat side view plastic package.
The epoxy package itself is an IR filter, spectrally matched to GaAs or GaAs on GaAlAs IR emitters
(Lp = 950 nm).
The large active area combined with a flat case gives a high sensitivity at a wide viewing angle.
In this project we need the top of the photodiode as the sensor area so you must leave it uncovered.
At this point we can work with the output signal of this photodiode which is quite enough to see
with an oscilloscope if your remote control works!!!
You can find the specifications for BPW41N at http://www.vishay.com/docs/81522/bpw41n.pdf
You need only 3 elements to make the remote tester & an oscilloscope to have a function view.
1. A good quality Male Metallic Rca
2. A Bnc Male to RCA Female adapter.
3. A BPW41N Photodiode.
Also you must use
A soldering gun less than 40W,
Soldering wire about 0.5” or 12mm,
A small cutter,
A small piece of cable (the cover) to use it as an isolator for the cathode of the photodiode.
You can solder the cathode to the main pin of the RCA & the anode on the ground body (coaxial), look at the picture.
Use the isolator included in the rca to isolate all the photodiode from the main ground,
plug the RCA to the BNC Adapter & put it to the oscilloscope input.
Turn on the Oscilloscope & place a good working remote control at 1-3 inches from the uncovered photodiode top.
Press any button and if your oscilloscope is a modern one use the auto range for the vertical & horizontal functions
at this point you can see a small signal for a few seconds when you press the button, this probably means that
your remote control works at least the button you pressed before, follow the procedure with other buttons.
Next step is to check a faulty remote control.
I wish you happy constructions.
Thank you.