- Tue Feb 17, 2015 3:17 pm
#10050
Then try also adding a small cap at the 433MHz module power pins. The 0.1uF is for power glitches. Try an additional 1nF or below to handle the noise.
- Tue Feb 17, 2015 3:21 pm
#10051
Ok, I'll try that tomorrow, because I don't have such small capactor at home. (You suggest 1nF, so 100x smaller than the 0.1µF I already have added, correct?) Can I solder both in parallel to the 433MHz power pins?
- Tue Feb 17, 2015 6:25 pm
#10066
Yes, in parallel. And you might have to do some experimenting here, with the value of the capacitor (it should be small though). You might also try putting the small cap at the ESP power pins.
They should always have linked grounds. It shouldn't work when they don't have linked grounds.
A picture of your setup might enlighten us, too. If you've got long leads for power they can certainly pickup noise.
Furthermore I think that it's no problem with WiFi/radio because if I power the 433MHz receiver by an external powersource and not by the Arduino, everything is fine. Only if the ESP and the 433MHz receiver are powered by the same supply (or atleast have linked grounds) the problem occurs.
They should always have linked grounds. It shouldn't work when they don't have linked grounds.
A picture of your setup might enlighten us, too. If you've got long leads for power they can certainly pickup noise.
- Wed Feb 18, 2015 3:12 am
#10085
Decoupling capacitors should not be made small on purpose. When using two capacitors, the point is to use two different technologies. Electrolytic capacitors are slow, and take good care of buffering power supply glitches or short time high demands (such as when the ESP transmits), while ceramic capacitors has a better high frequency response, filtering higher frequencies more efficiently.
The last paragraph in this Wikipedia article http://en.wikipedia.org/wiki/Decoupling_capacitor is a good general recommendation:
The last paragraph in this Wikipedia article http://en.wikipedia.org/wiki/Decoupling_capacitor is a good general recommendation:
Since capacitors differ in their high-frequency characteristics (and capacitors with good high-frequency properties are often types with small capacity, while large capacitors usually have worse high-frequency response), decoupling often involves the use of a combination of capacitors. For example in logic circuits, a common arrangement is ~100 nF ceramic per logic IC (multiple ones for complex ICs), combined with electrolytic or tantalum capacitor(s) up to a few hundred μF per board / board section.
