$5 Wemos D1 mini Pro ESP8266 Board includes 16MB Flash

Wemos D1 mini is one of my favorite ESP8266 development boards thanks to its small size, shield support, and low $4 price tag. There’s now a new version of the board – dubbed Wemos D1 mini Pro – with 16MB flash instead of 4MB for the original version, and a few other modifications.

Wemos_D1_mini_ProWemos D1 mini Pro specifications:

  • WiFi 802.11 b/g/n module based on ESP8266EX with 16 MB flash, chip antenna and external antenna connector
  • Expansion – Through holes with
    • 11x digital input/output pins (3.3V) supporting interrupt/PWM/I2C/one-wire (except D0 pin)
    • 1x analog input (3.3V max input)
    • Reset and power signals (5V, 3.3V, GND)
  • USB – micro USB port
  • Misc – Reset button
  • Power – 5V via micro USB or 5V pin
  • Dimensions – 34.2 x 25.6 mm
  • Weight – 2.5 grams

Wemos-D1-mini-Pro-ESP8266-BoardBeside the larger flash,  the main differences are listed in a Wemos forum post:

  • External antenna connector – switch by re-soldering resistor 0(zero) ohm
  • Built-in ceramic antenna – good!
  • New CP2104 USB-TO-UART IC – why? more stable?
  • Same size as D1 mini, but more light (3.9g -> 2.5g) – for flying devices? 🙂

Wemos D1 mini had a PCB antenna for WiFi, which may explain the lighter weight too, and CH340G instead of CP2104. The Pro board can run both NodeMCU or Arduino firmware like the original D1 mini board, and I understand the shields are still compatible.

Wemos D1 mini Pro is sold on Aliexpress for $5 plus shipping ($1.36 in my case) with male and female headers. The product is not listed on Wemos.cc website yet, but soon should be.

Thanks to Zoobab for the tip.

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zoobab
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CP2104, they could have at least exposed the GPIO pins of that chip:

https://github.com/ondrej1024/crelay
https://github.com/GBert/CP2104_GPIO

Occ
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Occ

These I/0 are controlled by the USB right? If so how would they be useful to the board?

Demetris
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Demetris

I didn’t get one point:
– switch by re-soldering resistor 0(zero) ohm
You need to remove 0 ohm to use external antenna or remove it so you can use the internal ceramic one?
And whats the problem keep the build-in antenna and use both(int+ext)?

Occ
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Occ

You move the 0 ohm resistor to connect the external antenna connector instead on onboard chip antenna. Using both would create impedance mismatch and result in poor performance

paul
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paul

Can anyone remind me of the type of External antenna plug required to fit that socket ? (and perhaps an online seller of good hi-gain antenna with that plug to save buying adaptor with associated loss)

@cnx Do the Shields for the previous wemos Di mini version fit the Di mini pro ?

Jeremy Therin
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Demetris :
And whats the problem keep the build-in antenna and use both(int+ext)?

The signal would be poor or may not work because impedance will not match specifications.

paul
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paul

@cnxsoft
Thanks for that reply. While waiting for it I did some googling which agreed with your advice, so added a number of shields to aliexpress basket and sent their ‘Ou Chen’ the following questions on aliexpress message:
1) Is the Ext Ant socket u.fl/IPEX ?
2) Are the shields for your previous ‘Di mini’ compatible with the new ‘Pro’
3) Will the D1 mino Pro work ok with many Di mini shields stacked ?
4) I am looking to add 2 channel 12bit ADC and a photodetector to cound LED pulses from a Mains Power Utility Meter
do you have a D1 mini shield for that ? – or if not, any suggestions ?
I am travelling out of UK soon so appreciate quick answer thanks.
That was some hours ago but as yet no response

paul
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paul

@paul
I got a reply from Wemos this morning confirming points 1, 2, 3

paul
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paul

@cnx the day after your article saying Wemos D1 mini was one of your favourites , I clicked on your link to Aliexpress for the D1 mini Pro and purchased it, plus some D1 mini Shields, about 12 items. Confirmation of my orders arrived promptly 20-40 day delivery to UK. I have not used Aliexpress before, and as timing is tight before I go to Brazil, thought to ask them if I can continue purchasing items on my UK creditcard for delivery to Brazil (which their site shows they deliver to) once I Add my Brazil address to my account. I was surprised not find a contact email/phone anywhere on the website. There is a ‘Chat’ button, but it is always greyed out, even during the Chinese daytime. All other retailers I have bought from eg Amazon, Abebooks) are contactable.

Do you know how to contact them as I feel nervous buying goods from a company that is uncontactable.

paul
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paul

@cnxsoft
Yes, I sent enquiries to Sellers via Aliexpress. Wemos replied 7 September. However, it may be uncommon for customers to alter their Delivery Address to different country without changing creditcard. I thought only Ali may know the answer, as payments go thru Ali, ‘sellers’ may not know where customers cards registered.

As I found no contact method for Ali itself, I sent above enquiry to seller Excellence Electronic where I placed most recent order (12 Nov) but their reply simply “Sorry, parcels can only be sent to the registered address”, just states the obvious, doesn’t say if Ali payments system still works when Delivery address changes to a different country to the registered card. Amazon & Abebooks do allow, but some UK etailers won’t. I successfully Added Brazil address to my account, however, that does not prove an order will be accepted on existing UK card for delivery to registered Brazil address. Reason want to know now, is would rather not buy more until after I arrive in Brazil.
An exception is rechargeable battery for the D1 Battery Shield best bought from AmazonUK to take with as I read rechargeables can cause postal problems. I asked Wemos via Aliexpress mail system which type Li-Ion OR LiPo they recommend for a D1 mini system, but as yet no reply.

You ask when I ordered. With time being short before departure I didnt wait for Wemos reply and ordered 4 items from Wemos on 6 Nov, remaining I2C sensor items etc from 5 other Ali sellers.

I later realised the pairs of 8 pin DIL male connector strips supplied with the D1 mini shields do not allow unpluggable shields without de-soldering, hence my late order to Excellence Electronic for ’20pcs Stackable Long Legs Female Header For Arduino Shield £2.51′. I only need 6 or 8 pcs, but saw no seller of 10. As Arduino & Wemos D1 completely new to me, am a little unsure about physical connection standard. I hope I am right in thinking Wemos pins, Arduino pins, Breadboard sockets, and ‘solderless jumper wires’ eg ‘fitTek 65 Pcs … Solderless Breadboard Jumper Wires [ASIN: B0087ZRVES]’ frm amazonUK, all connect to each other ?

Amazon also quote long delivery times on ChinaPost, but normally arrive about 2 weeks later, so I hope it is the same with Aliexpress ?

paul
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paul

@cnxsoft
UK Postal redirection to Brazil even for letters is astronomic, many 100 of times more than the value of goods ordered, and would of course destroy the all-important guarantee of ‘no receipt, no payment’ offered by all payment processor I have used. FYI UK post to Brazil typ 3 to 4 weeks unless paying extra. Guaranteed delivery is important: 2 items I ordered recently thru Amazon never arrived. Not all items from China are tracked post. (The Di Mini Pro & Shields have arrived)

Reason I revisited this thread, is you said Aliexpress should be contactable this week due to holidays last week. As they publish no email I tried their ‘Chat’ – Monday, Tuesday, and today – but no success, still greyed out. I know lots of companies demand you install multiple browsers. I keep my pc minimal, use only Chrome & for security, no Adobe flash, so that could be the reason Chat is greyed out ?

Might you have a moment to paste my question “Can a UK customer continue purchasing items on their UK creditcard for delivery to Brazil (which their site shows they deliver to) once they Add a Brazil address to their Aliexpress account. ? ”

That would test if the entity debiting my creditcard is contactable, and give some idea if I can buy from them in Brazil. If you visit their Contact us>Chat page and also find it unavailable, what other way can they be contacted ?
Amazon UK have multiple ways of being contacted, including standard email.

On 14 Sept I sent above query to an email on the parent company Alibaba site but no reply yet.