I have been looking at spinning my own April board and can probably get the cost down to below 10Euros. Would anyone be interested in purchasing one at this kind of cost ? Would only probably ship within the EU to keep things simple.
Anand, yes I’m based in the UK.
Will you be charging VAT?
I will be paying VAT, so yes… I’m pricing up exactly now but the total cost inc VAT will be around 10Euros. I’m not setup to operate as a business, so not VAT registered. Will this be an issue ?
if you can keep them at 10 euro’s count me in for one or two
VAT not issue so count me in for 5 to 10
Any chance you could choose a better DCDC regulator so that the board can be powered from a Lithium battery at 3.6V but still get those 6uA in deep sleep? Alternatively, make it so that the voltage regulator can be completely disconnected from the circuit so that the voltage from the battery goes directly into the Imp without leaking into the regulator?
I would get a few if I knew I could safely power the Imp with a 3.6V battery and get really low currents in deep sleep mode.
@drazvan: try a CR123. These are nominally about 3.0v. We are running some tests now and will be adding sw support to drop the minimum voltage required by the imp to about 2.5v which fits well with the CR123 discharge profile.
1500mAh, no PSU required and pretty cheap too.
hmmm… the lead time on PCBs is about 20 days, plus about a week to populate. Would this still be interesting ?, as it looks like coolcomponents will be shipping pretty soon in the UK.
The plan was to get about 100 made to make the cost worthwhile, but don’t want to be lumbered with too many
nigma CC have the imps but no boards, Adafruit will have boards v.soon.
I’m looking to for a Combi monitor/controller impee, battery &| line powered. It will have digital in, a Sensirion Humidity/Temp sensor along with a relay output.
So given the developments Hugo has posted above using a CR123 would be of real interest to me. Are you an electronics Eng? I’m not, so can’t tell what changes to an April base would be needed to support a 2.5/3v future?
Yes I am an electronics Eng and work at ARM so have a reasonable amount of experience in developing low power designs. I’ll draw up a design - but Hugo, if you have any reference designs available with the new voltages in mind, then that may be useful.
Looks like switching out the regulator with a TPS62170 might work. It’s basically the same, but with a variable output between 0.9v - 6v.
Anand, thanks for the heads up. I’m solutions designer working in building automation so I’m used to working with wired & wireless sensor & actuators that control lighting, HVAC (heating & cooling) systems. I’m building an impee that controls my radiator valves at home using a thermoelectric valves. I’m seeing if can cut my heating bills!
To make an april work with a CR123 you’d just need to not stuff the PSU chip at all. It’d just be the SD socket and ID chip.
Really for a production solution you’d want a UVLO too, but the most simplistic approach is just battery + socket + id chip
If you added a Max1555 you could run the board from usb/5v wall socket, and include the running-from and charging-of a li-ion battery
You would still need the TPS62170 or similar to take you down from 3.7v to 3.3v, but the ability to charge/run from li-ion would be handy.