Another possible board - ATMega328, nRF socket, DHT22 socket, MOSFET, Uno pinout

[Zeph]

I just ran across this; might be useful for our projects:

http://www.ebay.com/itm/331453072996

[RJ_Make]

Nice 1.25a MOSFET

[gregl]

Yes nice well thought out board.

Interestingly has ESP8266 port too....

[obstler42]

I just ordered a couple of those boards, sick of the mess wiring up the nrf24 modules ;)

will report once I have them working...

[EasyIoT]

ebay item location - not in China but in my city - wow :)

[obstler42]

I'm only 200km to the northeast, another reason why I ordered. shipped today, should arrive sometime this week instead of the 3-4w from china ;)

[pete1450]

Very nice board; almost seems like it was made for mysensors. I'm still too cheap though.

[obstler42]

I received my boards and already started taking the first one apart ;)

The board itself is nice, the problem is when you want to power it from a battery: the voltage regulator draws about 3-4 mA minimum, even when powering directly through VCC with 3V3. So sleep mode is useless. Removing the voltage regulator, it gets down to a standard 20 uA. So I will desolder the regulators and replace them with more efficient MCP1700 (which is a bit of a hassle since pinout is different)

[Mrlynx]

What regulator were the boards supplied with?

[bjornhallberg]

@Mrlynx I think it is an AMS1117. Quiescent current is probably higher I think? The spec say something like 5-13mA.

I wish we could all sit down and come up with a battery powered board or something. In the meantime I plan to try and make my own regulator add-on boards that can hang off of the boards I already have (despite being complete crap at Eagle cad). But it is hard to know how to design them to the plug and play so to speak. It'd be great if we could agree on some pinout. Perhaps we could all use the same pinout as the AMS1117, i.e. VIN-VOUT-GND?

[Mrlynx]

Basic problem is small LDO regulators in SOT-23 is power dissipation. Even if they are specified to give 250 ma they only can do that on small Vdiff (Vin-Vout).
On this particular board that hosts a esp8266 socket you need at least 215 ma@3,3 V just for the esp.
That means using beefier regulator and I am thinking about using torex xc6210 for my next project.

[bjornhallberg]

@Mrlynx Didn't know the esp8266 was such a power hog. I'm still going to go for Linear LTC3525-3.3 initially though.

The xc6210 looks promising though! What's the catch here?

Not sure about the part designation but it seems to be pretty cheap on AliExpress. In 50 or 100 pcs though ...

[AWI]

@obstler42 Got mine also

Beautiful boards! I "assembled" all 4 of them and will transform them into Sensors this weekend. At this moment I am powering the boards as shown. Measurement: 4 mA active, < 15uA when in MySensors "Sleep" mode.... nothing removed.. So I don't see any need for replacing/ removing the LDO..

Looks like a very good candidate for future expansion..

[korttoma]

@AWI Intresting radio module you got there! is it without PA but still with external antenna? Where did you get it?

[AWI]

http://www.ebay.nl/usr/alice1101983
http://stores.ebay.nl/txhangelectronic/

Not sure if i'am happy with these. The range does not seem to be much better that with the naked modules.

[axillent]

@bjornhallberg said:

The xc6210 looks promising though! What's the catch here?

I'm using for a long time xc206, it s one of the best to power NRF24
xc6210 should be also good. Any good proposals on pricing?

xc6206 i was purchased $5 per 100pcs

for esp it can be also reasonable to use DC-DC, it will be much more efficient
for example NCP1529 if you need 5V -> 3.3V conversion (1.7A)
or MP2359 if you need to convert any up to 24V (1.2A)
both requires just a few components and a very small SOT23 package
MP2359 costs about $20 per 100pcs and can be used widely
i use them for example to light up and dim strip leds

[RJ_Make]

@AWI Do you have an enclosure in mind?

[AWI]

@ServiceXp Not sure yet, probably a cheap ABS box. The enclosure suggested by the seller of this module looks like the perfect fit.. ! with an external antenna.

It can be found on on e-bay (name of the seller in the logo)

[RJ_Make]

@AWI I guess this would count as reason #18 to purchase a 3D Printer..... Yeah Like I need a reason to buy tech gear...

[therik]

@axillent said:

@bjornhallberg said:

The xc6210 looks promising though! What's the catch here?

I'm using for a long time xc206, it s one of the best to power NRF24
xc6210 should be also good. Any good proposals on pricing?

xc6206 i was purchased $5 per 100pcs

Just to add another option...I've been using the Fremont Micro Devices USA FT531JA. It has higher ripple rejection ratio than either of the above and is ~$20 for 100. Not as cheap as the xc6206, but much, much better ripple rejection. So, just another option that I found, it also has the same pin-out as the xc6210!! So, we can try them both with the same PCB design, cool.