WizFi250?

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jimmayhugh

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In my on-going search for a relatively inexpensive wifi solution for my TeensyNet project, Ive stumbled across this.

A quick google search of this site didn't reveal anything, so I thought I'd throw it out there for comments.
 
I ordered some ESP8266 chips from Aliexpress and am designing a simple Teensy 3.1 add-on with this soft-AP wifi capable chip. I have an NDA with espressif now and am getting good info about the chip from them. I expect to have a tested OSH Park board design with a pcb antenna that should be rather easily assembled with low temperature solder paste and a hot plate, include 128 Mbit SPI flash memory chip and mount either at the non-USB end of the Teensy 3.1 or standalone on a breadboard. I expect to sell them at Tindie for about $20, starting in May. If you can wait a few weeks, you can just order the boards from OSH Park and assemble your own wifi-capable Teensy 3.1!
 
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I ordered some ESP8266 chips from Aliexpress and am designing a simple Teensy 3.1 add-on with this soft-AP wifi capable chip. I have an NDA with espressif now and am getting good info about the chip from them. I expect to have a tested OSH Park board design with a pcb antenna that should be rather easily assembled with low temperature solder paste and a hot plate, include 128 Mbit SPI flash memory chip and mount either at the non-USB end of the Teensy 3.1 or standalone on a breadboard. I expect to sell them at Tindie for about $20, starting in May. If you can wait a few weeks, you can just order the boards from OSH Park and assemble your own wifi-capable Teensy 3.1!

I use UDP with my setup. I'll keep it in mind.
 
Oh...so many things are new to me!

So the application jimmayhugh has in mind is voice or video or some other realtime transmission, not wifi AP. I think I get it.

Still not sure that the ESP8266 isn't useable here...

For example from the ESP8266 brochure-

3. Features
▪ 802.11 b/g/n protocol
▪ Wi-Fi Direct (P2P), soft-AP
▪ Integrated TCP/IP protocol stack
▪ Integrated TR switch, balun, LNA, power amplifier and matching network
▪ Integrated PLL, regulators, and power management units
▪ +19.5dBm output power in 802.11b mode
▪ Supports antenna diversity
▪ Power down leakage current of < 10uA
▪ Integrated low power 32-bit MCU
▪ SDIO 2.0, SPI, UART
▪ STBC, 1x1 MIMO, 2x1 MIMO
▪ A-MPDU & A-MSDU aggregation & 0.4μs guard interval
▪ Wake up and transmit packets in < 2ms
▪ Standby power consumption of < 1.0mW (DTIM3)

In fact, if the Teensy 3.1 can be programmed via its hardware serial port (say, port 3) then this kind of chip could allow Teensy program upload via wifi, an advantage that the Edison now enjoys.
 
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I posted here a little while ago re ESP8266. The photo shows a ESP-01 attached underneath a Teensy 3.1 with the antenna protruding, I made a small adapter board (just a 3v3 regulator and a couple of caps) as Teensy can't provide enough current on its 3v3 output. I also have an adapter for the ESP-11, it's not quite as tight between the pins but it's harder to solder
There is an Arduino IDE for ESP8266 which works much like Teensy so I have both devices in the same IDE. I can program the Teensy as normal, then load a serial 'pass through' program to Teensy, switch to the ESP8266 in the IDE & program the ESP8266.
@jimmayhugh, the ESP8266 supports UDP. I've not used it but believe it's not entirely bug free...
@onehorse, at $20 you might not sell many :( I pay £2 for the ESP8266 and my adapter costs about £1

teensy_wifi.jpg
 
@onehorse, at $20 you might not sell many :( I pay £2 for the ESP8266 and my adapter costs about £1

I suspect some folks would like a plug and play option, especially if onehorse can furnish working drivers/sample programs.

Jim.
 
Hi Jim, there are no 'drivers' as such for the ESP8266, it uses a serial interface. I connect it to Serial1 in the above photo. I've tried to make it as plug & play as possible because it's for students to use.
There's quite a bit of useful info on these devices on the forum: http://www.esp8266.com/
I'm happy to share the design if anyone is interested, there are only three components on the board, they're surface mounted but easily hand soldered even with my eyesight!

Ian
 
at $20 you might not sell many

Perhaps, but I make them for myself first. If others find value that's icing.

Also, your adapter is not appallingly small; that is value subtracted in my view!

I note that I didn't expect to sell many of my nRF24L01+ radio teensy add-ons at $15 since the Chinese seem to be able to sell these at $2-3 each. But in fact these have proven to be popular and I have enjoyed such good sales that I have had to assemble new ones in batches of 8-10 every month or two. Next batch this weekend!

working drivers/sample programs

There is a nice website with a lot of info on this chip. I've never used the ESP8266 but I expect to at least write a Teensiduino sketch to exercise some of the chips functions. The Arduino IDE allowing programming of many of its functions just like any ordinary AVR processor will be very useful. I suspect there will be more capability added as the chip gains in popularity.

I can program the Teensy as normal, then load a serial 'pass through' program to Teensy, switch to the ESP8266 in the IDE & program the ESP8266.

Can we go in reverse? I would like to send programming through the ESP8266 wifi, store the program on the on-board flash, then pass the program to the Teensy via the hardware serial connection on serial 2 or 3. Perhaps there is a way to use the ESP8266 to allow wireless uploading of Teensy hex files? Does any of this make sense?
 
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Hiya Onehorse,
I didn't mean to question your motive. Maybe I should sell my adapter too?
Also, your adapter is not appallingly small; that is value subtracted in my view!
My adapter IS appallingly small! It's SO small that it's invisible to the naked eye! ;) That's an antenna you see in the photo, not the adapter :)
There is a nice website with a lot of info on this chip.
That's a very old page :( NOT a good starting point
Can we go in reverse?
I guess that's down to Paul. I don't see an obvious way to do this & it's not something I really need.
 
I didn't mean to question your motive.

Don't worry, no offense taken.

I expect to make my ESP8266 0.7 " wide (to fit on the Teensy) by ~0.8" tall including the antenna and breakout most of the useful pins.

Very interesting lecture notes, I am studying them in preparation for learning how to make use of this device.

Do you happen to know the size of the SPI flash on most of these modules?
 
Thanks for the info.

I am planning on feeding the board via Teensy VIN with a small 3V3 regulator; that way I can power the ESP826 with either USB or LiPo battery attached to my LiPo charger add-on.

I found a nice and small (2 x 3 mm) 4 Mbit SPI flash made by Macronix which I will use.

Ceramic antennas have poor (narrow) directionality; I prefer a copper wire AKA pcb antenna.

I looked at the Olimex board design. There seems to be a lot of options in configuring the pins for different functions, just like any microcontroller. I will have to get the detailed data sheet from espressif to decide how to design a full-featured board. The first iteration will likely just use RX/TX and break out a few other GPIO pins just to see if I can get something to work.

BTW, your attachment link is broken for me...
 
Sorry about the link, it was meant to be a jpeg - the board wouldn't accept my post without reloading... Try again...41horse.JPG
Sounds good - the ESP8266 CAN use a lot of current but it doesn't always. The MQTT example I cited idles at around 10mA (a chunk of this is for the LED)
Use it as a server, hit it regularly, & it gets hot!
I hate to say it on this forum, but the best way to save space is to leave out the Teensy :(
 
leave out the Teensy

The whole point is to use the ESP8266 to wirelessly interface to the Teensy, which is so much more capable as a microcontroller than the ESP8266 can be and has much better libraries and support.

Teensy for the work, ESP28266 for the commo link. That's the ticket!
 
I've just started looking into this chip. I think it should be straightforward to use it to talk wirelessly to the Teensy. I mean enable wireless data to/from the laptop and the Teensy, of course. That is my goal. I think if others want to use this as a general purpose micrcontroller, they have a tough row to hoe.

Although the advent of an Arduino-like IDE for the ESP8266 is promising.
 
@Onehorse - we have very different objectives. Mine is to educate aspiring engineers & show them different ways of doing things. I agree with you, the Xtensa CPU is no match for Teensy in most areas! I can remotely program Arduinos & not Teensys but that's not a big problem for me.
@stevech - This thing is flakey, but it's reached a point that I can use it with students :)

Ian
 
I'd like to learn more details about how you program Arduinos remotely. Do you have a link to your "class" materials?
 
I program Arduinos remotely using RadioHead protocols and compatible radios, plus my own bootloader and PC app.
 
My immediate goal is to get streaming data to a laptop from a remote Teensy with sensors on board. I do this now with the nRF24L01+ but I have to go through an intermediary (another nRF24L01+ receiver and UART from the attached Teensy).

I could use bluetooth for this purpose and it is on my list of things to do (using the nRF51822 chip, which I know works well). But developing blue tooth protocols is somewhat tedious and new to me. So...

I hoped it would be easier to design a simple, small breakout for the ESP8266 attached to the Teensy, then have data from various sensor add-ons streamed via wifi directly to the laptop to keep track of "stuff" remotely.

The next logical step is to not only receive data, but send re-programming to the Teensy as appropriate. Thus my (albeitlonger term) interest in remote Teensy programming via wifi or bluetooth. Wifi has some advantages over bluetooth. But i am no expert with either. I do know that we currently program our Edison applications exclusively via wifi as well as receive data from Edison managed sensors, etc. And this is very convenient.

Why can't we do the same with the Teensy?
 
ian / onehorse : not sure if this (4/21/15) will make a good 'partner to the Teensy' as a smart IOT radio module/co-processor but this ESP8266 based device is a stand alone Arduino programmable unit. It will have a working OTA/Cloud/Online programming - in addition to the direct IDE.

https://twitter.com/digistump/status/588069184669622272

It looks to support Serial / i2c / SPI. USB connector labeled 'for power'. So like a bare module you could connect to it serially from a Teensy, feed it data or offload a display for it as creativity allows.

If I heard right it will be somewhere between $9 and $13. At .92"x1.18" it won't be insanely small - I see a ceramic antenna or it would be bigger. And like his other work is has 500 mA of regulated power from 4.5 to 12v - so it could power the Teensy (given over 5.5v supply heat dissip. allowing) and have more than enough power to provide radio power too - the converse may not be true esp over 5.5v.
 
will make a good 'partner to the Teensy'

Of course, this is one solution. But my goal is to provide most of the same capability without the clunky Chinese module in order to make the add-on appallingly (0.7" x 0.5") small. I have already scoped the design.

It will fit on top of the USB connector with a 5 x 2 pinout and break out RX/TX on Serial 0. It will have a 300 mA LDO regulator on board feeding the ESP8266 directly from VIN. VIN can be powered by a LiPo connected to the separate LiPo battery charger add-on. The Teensy is powered by VIN (battery) also. I will use a pcb antenna of the same design as the one that works well on the nRF24L01+ radio add-on. It will have a super small 4 Mbit SPI flash chip. I will breakout as many of the GPIO pins as possible, but start wth just two or four to make it easier and smallest. If it works, I ought to be able to spew data from I2C sensors attached to the Teensy 3.1 directly to the ESP8266 via Serial 0 and then have the ESP8266 send the data wirelessly to a serial monitor (putty) on a laptop.

Now that would be cool!

The components are relatively inexpensive so that the Tindie price will be well under $20, but I have to get it designed, assembled, and working before I even consider trying to sell any.

Still not quite sure if the bare chips I ordered come loaded with firmware or if I have to load the flash with the firmware somehow. Still a lot to learn...
 
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