- Mon Mar 27, 2017 12:21 pm
#64284
After successfully prototyping some stuff on NodeMCU devkits, I'm ready to produce something a bit more "final".
I picked the ESP-07 because of the possibility of the external antenna, even though it means more work (soldering to a breakout board, etc.) I am lazy and would have preferred a WeMos style, ready-to-go chip, with built-in USB, but didn't want to lose the antenna*.
Anyway, I got the chips and the breakout boards, and even managed to solder them without incident (my first ever SMD soldering
) using paste but with an iron, as I don't have a hot-air gun. No problem, all fine, and I flashed the the chips with the "cloud build" I wanted without incident.
Now what I want to know is:
1) The ESP-07 has two antennae, the on-board ceramic one and the receptacle for the external one. Are these two DESIGNED to work together?
In other words, will it work better with the external antenna if I remove the ceramic, or will it make no difference? Perhaps it might even be detrimental to the chip, especially if at some stage it finds itself working with no antenna at all (by mistake).
My knowledge of such RF technicalities in next to zero, hope someone can pitch in here.
2) The breakout board I used (pretty standard from the various auction sites) has a solder pad on the back for a 5V to 3.3V converter/regulator. There is also a short-circuit (0 ohm res) on the board. If this is not removed, the 3.3V chip pin goes directly to the VCC breakout pin. If that happens to be 5V there may well be a problem. If it's removed the 3.3v passes through the converter first. This is what I'd like to do, as the rest of the project is working at 5V, and it will save me from having an external converter (as I do at the moment). So I ordered a few AMS1117s, since that is what I've seen being used everywhere else.
However, when I checked I found that not only are these chips WAY too wide for the pad (about double) they also have the wrong pin-outs. The pads on the breakout board are: left-GND; center-5V; right 3.3V -- whereas the 1117s are left-GND; center 3.3V; right 5V.
Does anyone know if there is another regulator that will fit on this pad, or is this just an example of the bad design that occasionally finds its way into cheap products from the Orient? Any suggestions appreciated. I mean, no big deal to have the regulator external but if there is a better, on-board solution so much the better (Basically a regulator with the right pin-out),
Many thanks!
Below is a pic of the reverse of the breakout board. I'm not even sure it's the right scale, but seems reasonably similar to mine:
* PS. I just saw that there is a WeMos board available with an external antenna, the so-called "Pro", but it costs more than double the price of an ESP-07 and has no RF screening. It does claim to have 16M flash though, which is cool but not something I need.
I picked the ESP-07 because of the possibility of the external antenna, even though it means more work (soldering to a breakout board, etc.) I am lazy and would have preferred a WeMos style, ready-to-go chip, with built-in USB, but didn't want to lose the antenna*.
Anyway, I got the chips and the breakout boards, and even managed to solder them without incident (my first ever SMD soldering
) using paste but with an iron, as I don't have a hot-air gun. No problem, all fine, and I flashed the the chips with the "cloud build" I wanted without incident.Now what I want to know is:
1) The ESP-07 has two antennae, the on-board ceramic one and the receptacle for the external one. Are these two DESIGNED to work together?
In other words, will it work better with the external antenna if I remove the ceramic, or will it make no difference? Perhaps it might even be detrimental to the chip, especially if at some stage it finds itself working with no antenna at all (by mistake).
My knowledge of such RF technicalities in next to zero, hope someone can pitch in here.
2) The breakout board I used (pretty standard from the various auction sites) has a solder pad on the back for a 5V to 3.3V converter/regulator. There is also a short-circuit (0 ohm res) on the board. If this is not removed, the 3.3V chip pin goes directly to the VCC breakout pin. If that happens to be 5V there may well be a problem. If it's removed the 3.3v passes through the converter first. This is what I'd like to do, as the rest of the project is working at 5V, and it will save me from having an external converter (as I do at the moment). So I ordered a few AMS1117s, since that is what I've seen being used everywhere else.
However, when I checked I found that not only are these chips WAY too wide for the pad (about double) they also have the wrong pin-outs. The pads on the breakout board are: left-GND; center-5V; right 3.3V -- whereas the 1117s are left-GND; center 3.3V; right 5V.
Does anyone know if there is another regulator that will fit on this pad, or is this just an example of the bad design that occasionally finds its way into cheap products from the Orient? Any suggestions appreciated. I mean, no big deal to have the regulator external but if there is a better, on-board solution so much the better (Basically a regulator with the right pin-out),
Many thanks!
Below is a pic of the reverse of the breakout board. I'm not even sure it's the right scale, but seems reasonably similar to mine:
* PS. I just saw that there is a WeMos board available with an external antenna, the so-called "Pro", but it costs more than double the price of an ESP-07 and has no RF screening. It does claim to have 16M flash though, which is cool but not something I need.
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Last edited by alex_g on Tue Mar 28, 2017 2:33 am, edited 1 time in total.
