I presume the work @bitbank has been doing would be reusable in all or part - just you’d be using the computer itself computer as one endpoint instead of two devices. Right now I’m looking at other Arduino Zigbee options just to get the ball rolling.
I bought a ZigBee/ZWave USB dongle and the issue seems to be that it doesn’t let you read/write raw packets, but forces you to conform to the protocol. This presents a problem because it would require a lot more software on the ATmega128RFA1 to support the protocol. I’m still looking for a simple way to connect a raw 802.15.4 transceiver to the PC. Sacrificing an XE unit is a lot cheaper option than buying one of those USB dongles.
Does that look right? I need to look up the software library though for the XBee and see what all is there. It sounds like the Series 1 chips are a lot simpler to work with and support 802.15.4… but is that the “protocol” you are referring vs raw packets? From the quick reading I did it made it sound like 802.15.4 describe a way to “encode” a packet… not necessarily a super heavy protocol. But I could have it all wrong.
The protocol involves doing device discovery across the channels and establishing a connection from a master to a slave device. Atmel published some software to run on the AVR that implements the protocol. Both of those devices are a lot more expensive than a sacrificial XE unit.
But the XE units are worthless for talking to my computer if I’m not really wanting to solder a serial port onto them. Vs something that comes ready to go out of the box.
Another idea is to use an ARM SBC since it has SPI exposed and use it to talk to an XE through the pogo pins.
Actually it’d need to be cheap to make it viable for a lot of people. I was imagining what if you found a way to acquire a large number of these (from a large school system or something)… AND had a cheap/easy way to program them (wirelessly)… AND wrote a custom firmware/dev library… and did something like a Kickstarter or IndieGoGo to make it more “mainstream”… we already know the units themselves are inexpensive… I presume if you found a mass source of them you’d get them even cheaper… the unsolved part for me would be where to get a bunch and how to reprogram them easily.
And would anyone be interested in that?
The pogopin adapter @is0-mick sent me is pretty awesome but kind of hard to hold into place just right… I don’t know if that would be a great answer if you were doing this “in-mass” and wanted the units to be easily programable… obviously wireless is the next thing you think of… but now you need some sort of cheap wireless gizmo to provide along with the XE, hence my wondering about this.
Obviously what I linked to isn’t that (the cheap solution)…
Regarding a nice official library I think the keyboard/flash/graphics stuff is well within my grasp (@bitbank has gotten us off to a great start with a workable foundatiion). I wrote/rewrote half of the graphics stuff for Arduboy at least. If we wanted to have a kick-ass network stack that might or might not be within my grasp. But hopefully if people were interested they would also contribute - since the units themselves are easy to get and already out in the wild.
Two battery elimination ideas -
Single battery plus tiny 3.3v boost converter:
Or two batteries with shunt to remove 2 (it runs fine on 3v):
What purpose would requiring 4 even serve?
The 4 batteries’ output (6v) is sent to a 3.3v buck converter. Energy is wasted stepping down the voltage (a little), but the 4 batteries have more total energy than 1 or 2 and will keep the device running even when the voltage on each drops below 1V. This will allow it to run for a long time, but tends to cause acid leakage because the devices are left for long periods of time with a slow draining of the batteries. The boost converter in the photo above can operate down to 0.8V, so it can make 1 battery last a pretty long time too.
Getting a CC2531 based USB dongle “might” be a solution. I believe the MCU allows working with the raw packets in a similar fashion to these ATmega128RFA1 MCUs. But, it requires learning yet another microcontroller architecture and compiler (SDCC potentially) and buying another proprietary programmer (cheapest I have found is the SmartRF04EB)
- CC2531 module: https://www.aliexpress.com/store/product/p/1829717_32769663830.html
- SmartRF04EB USB downloader: https://www.aliexpress.com/store/product/p/2180007_32673666126.html
- Adapter cable: https://www.aliexpress.com/store/product/p/2180007_32916575492.html
I bought one of the SmartRF04EB USB downloaders so I could mess around with the Smart Response PE devices, but am still waiting for it to arrive.
Why not just use a small lipo or cell phone battery?
They provide a good voltage range and great capacity vs. volume/weight. Micro USB charge/protection modules are super cheap too (search for TP4056).
For cost and fire hazard reasons, I wanted to stay away from LiPo, but that’s just my feeling about it. There’s also a certain benefit to being able to just drop a AAA or AA battery into something and have it work.
To each his own I guess.
I personally much prefer LiPo (or more accurately Li-Ion) cells. At these small sizes they aren’t really all that hazardous, and are actually pretty inexpensive. I mainly like being able to just plug in a micro USB cable and charge it up without having to remove AA cells to replace them or recharge externally.
The newer low self-discharge Ni-Mh AA cells (i.e. Eneloops) are pretty good, but are fairly costly themselves. I detest the older Ni-Mh AA cells that never seem to have much charge left when I go to use them. And, I’m done with non-rechargeable cells as much as possible.
Just got the hands on the Smart Response XE. It seems that U6 (next to the RS232 header) was planned for the MAX3221 (and the surrounding caps should be ~0.1uF).
I plan to solder it and aleady installed a RS232 Socket behind into the case. Any Idea what “U5” could be (near the ISP header)? Seems to be some kind of I2C peripheral.
I’ve published my wireless bootloader code and uploader sketch to Github here:
My blog post with details about the wireless bootloader:
Hackaday published it:
Received my set of 36 XE’s today. Random inspection shows that they’re clean and working! Anyone who still wants some (in the USA) hit me up and I’ll give you a good deal.
Working on a new project today with a Bosch BMI160 IMU and DS3231 RTC
How many do you have now? Must be quite a pile.
Suddenly I have to think about marbles