Showing posts from November, 2020

Challenges and decisions ahead!

 So, a few weeks ago Pycom announced this- Aside from the implications this has for the case (eeeek!!!!) this may have positive ramifications. Firstly, it looks like an RTC will be onboard. Secondly (and I'm really hoping) the tetchy (technical term) IO expander will be sorted. Thirdly, we could change up a gear and fit the more powerful PN532 NFC reader. There's already a circuit python library available so it won't take much to adapt it to micropython. Watch this space.... I really hope it fits in the current casing though....

Mesh networking works!

 So, one of the key features I wanted to implement in this project was mesh networking. Pycom have their own implementation of it, called Pymesh, so I figured it would be ok. One look at the docs was quite confusing for a novice like me, however on closer inspection it was integrated in the Pybytes (Pycom's online dashboard/gateway). I am already using the release feature in Pybytes to push code to the devices over wifi, which means the USB post does not need to be accessible, so using Pymesh that way made sense. The benefits of Pymesh- Mesh networking over LoRa Self healing Allows cheaper no LTE devices to be easily incorporated The downsides of Pymesh- Not sure if I can use the things network at the same time - need to check this! Longer boot time Greater load on the microcontroller processing capacity

Getting Organised

 So after finishing prototype one and two, it was apparent some internal organisation was needed. Whenever the case open and closed, care was needed to stop wires getting caught in the hinge. Now obviously I could do a much neater job with a ribbon cable, but that's very fiddly and I don't have ribbon cables to hand. But I do have cable ties, and they did the job. Very annoyingly the switch on the final device (ironically Timer001) is soldered the opposite way to the other two. My fault but still annoying and I didn't realise until the switch was glued in. Also, this was the first time I used hot glue to reinforce the connections. it doesn't seem to have caused any issues so I'll make it feature of the rest. Pycom have also said they will be releasing a new LTE antenna soon, which should have greater gain than the current antenna, which is positive. In other news, the three prototypes now have their own flightcase, which is great! 

Like blu-tac, only stronger

 A brief update - following my left arm being rendered useless for a short period of time I now have some use coming back to it. Not full range and definitely nowhere near full strength, but enough to support bits and pieces, hold solder etc. Which means I've had chance to test out my new glue -  JB PlasticWeld Epoxy Putty - and it's great*! It comes in a tube, you cut of an amount (not much is required) mix between your fingers until a uniform consistency and colour is achieved, and then mould into the required shape. I used it to create mounts for the standoffs (new shorter ones - see the next post) on the ABS casing. Something standard epoxy just hadn't done well. To make sure they held, I coated them in PlasticWeld Epoxy .  You can see the standoffs in the photo below, just to the left of the power switch- *I'm not being sponsored for this and am in no way connected with JB Weld, their product just did what I needed to, really well