Tony Cox

My dentist is getting into the festive spirit! 😬

And with your lightsaber, apparently. :)

You have to admire the tenacity of this old ash tree.

Nice. I see what you mean about the two C/E amps - I was trying to picture what that looked like. A lot of switched caps!

Ah, hence the tripler and doubler :)

Franklin oscillator?

Oh no, I feel a weekend-shaped rabbit hole approaching…

Assume that was the intention? - or just happy side outcomes? 😉😄

More or less complete. Added auto-cal and (after a couple of dead ends) I got Tx back-off working using LoRa’s channel activity detector (CAD) system. Packet Tx will delay up to a limit and if still stuck they are dropped. Reduces collisions dramatically when traffic is high.

They pulled a similar rentware-only trick when they swallowed Eagle. But it turned out to be a good thing because it prompted me to ditch Eagle and move to Kicad. Never looked back (bonus: it imports old Eagle projects pretty well).

Writing to an EEPROM *safely* via I2C and avoiding bus lockup during frequent hardware interrupts triggered by LoRa network packets arriving is REALLY hard!

In fact, most time was not getting it to work - but making it work reliably. Finding all the edge cases, checking call returns, validating data packets and types - generally coping with a system that mangles data regularly.

The tricky part was not getting data down, but sending a periodic timestamp up to each sensor and storing it. It took several tries with different approaches before I found a model that worked.

After several weeks of learning about LoRa networks my sensor network is finally running. Custom sensors based on a RAK3172 broadcast to a Heltec LoRaV3 receiver which filters and aggregates data. This sends the data via a high speed (wired) UART to a NodeMCU. This bridges data to WiFi and MQTT.

Floral theft! This bee is far too big to crawl into the Hosta flower - so it heads up to the neck of the flower, cuts a neat hole and “steals” the nectar. Crafty 🐝

I see Greater Anglia Trains don’t have Ticket Inspectors any more - they have Revenue Protection Officers. Jeez.

While you are contemplating that, spare a thought for those who are struggling with a 9 letter word that clearly doesn’t have enough vowels… 😉😄

assigns, against all people forever. In witness whereof I have affixed my seal to this my present charter. Given on the tenth day of January in the nineteenth year of the reign of King Henry the Fourth after the conquest of England.

to hold the said tenement with appurtenances to the said John, his heirs and assigns forever. And I, the said William, and my heirs will warrant the said tenement with appurtenances to the said John, his heirs and

formerly belonged to Henry le Walshe and afterward to Thomas, son of the said Henry le Walshe, and afterward passed to the said John by the gift and feoffment of the said Thomas, as is more fully contained in certain charters made thereof. To have and

ChatGPT suggests:

Let those present and future know that William of Cheltenham, clerk, has demised, granted, and by this present charter confirmed to John Tacyne one tenement with appurtenances in Westherdecote, which said tenement

Stinker! #RIFA

The ‘shop stinks now - a RIFA cap in my HP436A power meter decided randomly to give up the ghost after being plugged (but not turned on) for an hour. 👃🤷‍♂️

Constant current circuit test

Constant current source is working well. Stable 250uA with a diode to add temperature stability.

RAK3172 IC

RAK3172 footprint

This is definitely going to be a soldering challenge. It may be time to invest in a hot air station.

These Heltec LoRa V3 dev boards are really good for learning/testing ideas but with only 36 pins (many performing overlapping, incompatible functions) you rapidly hit limitations (eg external SPI conflicts with SX1262 radio chip). The docs are a bit limited too. So it’s Kicad time.

(And I need to work out how to turn off that orange LED which sucks 4.5mA continuously).

What I need now is a small 250uA constant current source for the RTD. I’m thinking a diode-compensated LM334…

My LoRa cryo-freezer monitor is coming on nicely. Doesn’t look much but PT100 RTD, battery monitor and door open sensor are all working. Power to RTD only switched on while reading. “Power is everything”, as they said on Apollo 11.

Help please! Can anybody identify this pcb-mounted wire press/clamp connector?

Experimenting with a couple of LoRa sensors. The Heltec LoRa ESP32 v3 boards seem capable and easy to set up in the Arduino IDE. They come with neat 3D printed cases. The ESP32 ADC is not great - but with careful calibration it’s ok. Will be interested to see how long the 1100mAh LiPo lasts.