uAmp 08M2 Idle


New Member
A bit of a scenario but... I have been setting up ultra low power long distance IoT Penguin nest box thermal telemetry based on DS18B20 remoting over bare 433MHz ASK into Raspberry Pi and uploading to Cayenne free IoT dashboard... Great fun if you have not used this sort of idea as it brings your picaxe up on a free / public share-able dashboard / phone Ap with free txt and e-mail message alerts etc. I have developed a kind of uData protocol called 'Cicadacom' - separate topic...

To get each penguin coloney of 4x DS18B20 nesting boxes connected to one 08M2 lasting long enough (one year + off 3x AA Alkaline ) I have found this works nicely:
'Select uPower Sleep mode
pokesfr %01110111,%00000011
'VREGCOn register low power sleep mode
'Normal = %01110111,%00000001
'PIC12(L)F1840 Data Sheet'

IF you connect pin 3 Hi or Low then this can cut idle current massively from several 100 to decimal uAmps
IF you used DISABLEBOD then you can drop into the single digit uAmps
Shed bench I have managed 0.6uAmps in the sleep / nap mode
An interesting calculation to take a CR3012 and divide the above idle current into it's nominal 240 mAh capacity.
Try it !!!

Beware of effeects of serial programming leads when getting right down the bottom. Un plug to test 'actual' uAmps. I note the AXE-027 nicely less effects things but ancient XP UARTS (shed here) can affect things big time...

Tip... DS18B20 work nicely using internal WPU so you can save on those pull up resistors and all that extra soldering. This reduces the project complexity and system to 1 battery + chip + the ASK RF Tx module + 4x temperature sensors

~ Andrew


Senior Member
Nice. You don't appear to have any antennas on the ASC Tx modules--is that the case? And you get 100m well enough? Which modules?

It looks like I'm seeing photo sensors on some of them--are you using those as well?

To get 4 DS18B20s on one 0M2, are you using one-wire? How far between nesting boxes? Star wiring? Is the whole project written up somewhere?


New Member
Apologies for being a little cryptic...

>>> You don't appear to have any antennas on the ASC Tx modules--is that the case?
I find the nice rock solid Dorki Simple ASK is best. I can get these to work easily around the classroom / house with Zero antennae. The Dorji small ASK TF Tx module has a practical 4th pin antennae that can hook onto any bit or wire / metal. This soldered into one of Stan's antennae ideas when tuned up has worked up to 900m LOS from an up stairs window.

>>> And you get 100m well enough? Which modules?
With an approx Stan calculation + an end factor = total length of up to 15cm 'bit of wire /1/4 L I find I can get a few blocks well past 100m and in beach / rural setups 300m is not uncommon. A super efficient radio data packet that is designed around RF Rx module bit slicer makes all the difference + a check sum = 99.99% reliability. and doubles range

>>> It looks like I'm seeing photo sensors on some of them--are you using those as well?
As above this is my general working concept. The breadboards are for demonstration of the general 'Cicadacom' concept. I have a concept going called 'Data catchers' where students (pre school and up) count decadic blinks (or beeps) Long = 10's and short = 1's Kids rush about measuring Temp, Lux, moisture (readadc or Touch) condctivity) and mm water level ( = bit of wire + touche sense) The RF Tx module here is an optional bolt on that transmits school ground data to a Pi that MQTT Posts data into www.cayenne.mydevices for free. See following images.

>>>To get 4 DS18B20s on one 0M2, are you using one-wire?
I am using a trick on pin 5 + the Disconnect command. Pin5 is perfectly ready and waiting usable general purpose DI / Readtemp pin. The WPU command means you can do this with NO components at all. Just the chip and a battery :)
(perhaps we make this a sep topic if you want the code...) Just to be a complete tease... Pin0 works with WPU and readtemp command also so you can read up to 5x DS18B20 + one chip and a battery and no method of doing anything useful with the information ! I store the data into internal 08M2 spare EEPROM.

>>> How far between nesting boxes? Star wiring? Is the whole project written up somewhere?
Maps to follow...
So one 'Node' and multi 'Data Catchers' = star I guesse. This is made up of one RF Rx Raspberry Pi with the matching Dorji RF Rx ASK module high on a window sill somewhere. This listens to ad hock Cicada 'Cirrrups' that look like
85,85,85.:01,A,data,CS = to about 10 bytes total.

Any number of data catchers typically a few dozen can be multi hardware sensors or multi channel light, temp water mm from stand alone chips or mixes or real hybrids:
Channel A = value
Channel B = MIN + C MAX (reset when sun passes overhead and resets the solar RTC)
Channel Z = Battery mV using calibadc completely internal calc as a battery check

Cicada chirrup looks like:
85,85,85.:01,A,data,CS = about 10 bytes total. with a big fat nap 10 between chirrrups.
Preamble of50% ones and zeros + 'NodeID' + Channel Number + Data (byte or word) + XOR byte of all the preceding.
The RF Rx Pi listens to the filtered, check summed 'clean chirrups with the long body Dorkji ( the RF Rx ASK module = best sensitivity I have found ) Again a simple 'stick of wire' 1/4 L on breadboard works just fine. The Cicadacom concept is super dumb. RF Rx module one chip and 10 bytes into a breadboard powered by the Pi. It is super lite weight, simple ad hoc, zero handshaking. Yes collisions occur ( < a few percent ) but these are simply thrown aside. The temperature of a penguin water level / climate does not change that much in a minute or two.

The Pi takes the cleaned up re packages data as txt based CSV into ttyAMA0 of a Pi0w ($25) that is registered with cayenne mydevices. 12 lines of python in the Pi forward via their secure and stable data handling platoform. In my case the cayenne forwards vanilla analogue float blob numbers with anon units. Cayenne Can recognises 100+ key word SI Units and values = seriously nice.

When the data hits the com port of the Pi the value is time and date stamped and is available to 'all mankind the whole world over' in the cloud immediately. Even nicer... When a NEW channel appears by a kid turning on a picaxe a new channel is set up and data starts to be stored with time and date stamp in front of you on a www page without having to do Anything. Data can be filtered, SQL?, plotted, operate a big pointer widget, plot with a 'downlaod to xl button on it for m h d w m y or any custom time frame.

AO / DI / DO is all there too
Lots of fun

~ Andrew
(Pix coming up)


New Member
University of Shed ground level (roof of car 1/4 L isotropic proporator)

YEPT Otago Peninsula.jpg
Yellow Eyed Penguin Trust preliminary field test Dunedin Sth NZ