Requirements

Project requirement document

Requirements ESP32 Boards shared spreadsheet

Requirements Overview

	Requirement	Discord username	Category
1	Support different ESP modules	wassfila	uC
2	power cut-off circuit + RTC Timer	Informatic0re	power
4	3v3 Output	Andreas Spiess	power
5	5V Output	Andreas Spiess	feature
6	USB charging	Andreas Spiess	charging
7	Solar charging	Andreas Spiess	charging
8	Charging while powering	Andreas Spiess	charging
9	Replacable batteries	Andreas Spiess	battery
11	Low voltage signal/alarm/interrupt	Andreas Spiess	power
12	Battery low voltage protection	Andreas Spiess	battery
13	Over charge and discharge protection	Andreas Spiess	battery
14	charge indicator	Andreas Spiess	charging
25	Charger control (enable/disable)	tealbrains	charging
26	Li-Ion Chemistry as 18650, 16340 and FlatPack	tealbrains	battery
28	Hysterisis between battery low and battery ready.	metimmee	feature
32	Modular architecture with optional components	wassfila	organisation
33	Test Points	Informatic0re	feature
34	Expose ESP32 Serial pinouts for flashing	wassfila	uC
35	LOW power consumption (of the regulator board itself)
37	Usb C	fabrifer020	feature
38	Reverse voltage protection	fabrifer020	safety
40	Controllable 3v3 Output	leven
43	Expose Battery pins (post protection)	tealbrains	feature
46	Having Both Holder And Connecter	Trance_Paradox	feature
50	Short Circuit Protection on the output	johnheuk	safety
53	Barrel Jack / Screw Terminals	johnheuk	feature
63	Expose unused ESP32 GPIO Pins	wassfila	uC
88	Open Hardware License	Noki

All Initial Requirements

	status	Requirement	Discord username	Category	Why ?
1		Support different ESP modules	wassfila	uC	ESP32 WROOM, WROVER, S2
2		power cut-off circuit + RTC Timer	Informatic0re	power	Cutting off the power lowers the current draw to <1mA
3	rejected	Actionable documentation	LEMD49	organisation	Containing: principles & block diagram, wiring diagram, BOM w all components and mechanical parts / connectors, Normal operations levels (can be notes on cct diagram), troubleshooting flow….
4		3v3 Output	Andreas Spiess	power	Power supply for MCU
5		5V Output	Andreas Spiess	feature	Usefull for sensors which need 5V but should have a on/off
6		USB charging	Andreas Spiess	charging
7		Solar charging	Andreas Spiess	charging	Power for the system when it is installed in locations where USB is not available and where swapping the battery every year or so is not desired
8		Charging while powering	Andreas Spiess	charging
9		Replacable batteries	Andreas Spiess	battery
11		Low voltage signal/alarm/interrupt	Andreas Spiess	power
12		Battery low voltage protection	Andreas Spiess	battery
13		Over charge and discharge protection	Andreas Spiess	battery
14		charge indicator	Andreas Spiess	charging
15	rejected	Maximum Battery life ( e.g. sensor mode current < 50uA, life 1 year)	wassfila	feature	Define the maximum achievable savings by the modular design, (e.g. short wake up, send ESP-NOW packet and back to sleep). I set 50 uA arbitrarily as suggested by tealbrains an anyone please feel free to vote or update
16	rejected	Minimum Battery life (e.g. performance mode current <200uA, life 3 Months)	wassfila	feature	Set a target for the least achievable performance of the modular design, e.g. when deprived from all external optional components. e.g. no external RTC.
17	rejected	Specify a maximum quiescent current	tealbrains	organisation	(Instead of 15. and 16.) Lifespan of device will be application dependent. The property of this circuit must be independent. For example, fix quiescent current to be < 50uA.
18	rejected	ESD security	RV3Dtech	safety
19	rejected	I2C Interface & Arduino Library	RV3Dtech	feature
20	rejected	Security of supply of the components + 5y	RV3Dtech	organisation
21	rejected	Breadboard friendy design	Informaticore	feature	you know why
22	rejected	Multi-chemistry	tealbrains		Some users may use Li-Ion, others may use LiFePO4. NiMH is broadly available
23	rejected	Temperature (over and under) protection	Thomas	safety	Safety (can’t charge battery at any temperature, there is a risk of damage), can be part of the charger IC
24	rejected	Battery heater	Thomas	feature	If used in cold areas there might be many weeks/months of continious battery temp too low for charging.
25		Charger control (enable/disable)	tealbrains	charging	Reduce the number of charging cycles (specially for solar applications, where we may not want to charge the battery constantly) in order to increase lifespan of battery. AND allow to measure the battery voltage accurately
26		Li-Ion Chemistry as 18650, 16340 and FlatPack	tealbrains	battery	Some users may use Li-Ion 18650 and 16340 or Flat Pack
27	rejected	LiFePO4 Chemistry	tealbrains	battery	Some users may use LiFePO4. The chemisty is better for cold climates.
28		Hysterisis between battery low and battery ready.	metimmee	feature	Solar devices in winter may bump along at minimum voltage for extended periods. For some applications, it may be better for the micro to go to sleep for an extended period to allow the battery to charge more than the minimum amount.
29	rejected	Optional OLED based small info display	Wajid	feature	can display self health and other parameters without being attached to target system
30	rejected	cascading option for increased power	Wajid		for example some project need more power then it can simply stack the power supplies to increase power
31	rejected	Designing a full featured (one or more) board and a standalone board for “any” application with the same requirements.	Vincent (inspired from Discord - I do not remember the name of the author…)	organisation	It allows to have a ready to go board. Or to have a module.
32		Modular architecture with optional components	wassfila	organisation	Although this might be the main idea already, I added it as requirement to refer to it and translate its impact on the design. This might have to be broken down into what is modular and what not ? RTC optioanl, ESP32 itself optional as mentionned in req_31 ? …
33		Test Points	Informatic0re	feature	We need test points at any usefull position for proper validating of the circuit
34		Expose ESP32 Serial pinouts for flashing	wassfila	uC	If we plan to have a module soldered on the PCB, we would need to flash it, a serial to usb converter might not be necessary to be on the pcb as it could be similar to the ESP32-cam with external serial to usb. Use https://randomnerdtutorials.com/esp32-pinout-reference-gpios/ as aa reference (very good) And do not expose GPIO36! Ask Informatic0re why
35		LOW power consumption (of the regulator board itself)			In Solar powered applications, the overhead power consumtion of chargers/regulators can be too much.
36	rejected	Wemos D1 mini shield			It is nice to have the power board directly fit on the Wemos D1 mini as many other shields
37		Usb C	fabrifer020	feature	This will make it more future-proof and its going to be nice to have the new usb standard while not having to worry about wich way you connect the usb
38		Reverse voltage protection	fabrifer020	safety	To not fry our Boards with a common mistake that could be prevented with just a few components and negligible current loss for saving our boards
39	rejected	Adjustable output voltage (buck/boost)	davidfet	feature	To allow the board to be used for multiple projects which may have varying power requirements
40		Controllable 3v3 Output	leven		A 3.3V Output which can be tunred on and off by the MCU to power sensors and other things
41	rejected	Create (1+) standard slots for expansions	tealbrains		Some features are “nice to have” such as additional buck / boosts, or power bus controls. Ultra-low power modes such as using an RTC + SRAM. These features are not “core features” so leaving the slots unpopulated by default will allow the team to develop some expansions and the users to also develop their own expansions if they need to.
42	rejected	Define maximum/minimum acceptable size	tealbrains	dimensions	This will limit the number of options, connectors, etc and requirements that can be met. Is having a connector for 18650 for example a good idea? Or 14500? etc
43		Expose Battery pins (post protection)	tealbrains	feature	This allows the user to power some modems or loads directly from the battery without extra losses that occur using a voltage regulator
44	rejected	Power on-off behaviour, similar to a mobile phone	Florian	feature	Possibility to power off via a button and via a MCU signal. If external power transitions from off to on while the board is powered off because of low battery, then power it on. But do not power it on if battery level is OK, indicating powering off was intentional (via power off button or MCU signal). This behaviour would be helpful when the external power is intermittent (solar pannels, mobile units similar to a phone). It would allow automatic restarts when external power is available after a powerdown because of low battery, while allowing for voluntary shutdown too.
45	rejected	Support For ESP 32 Modules	Trance_Paradox	uC	Support for different Modules like ESP32-Wrover, ESP32-Mini, ESP32-Wroom etc And providing breakouts for those also
46		Having Both Holder And Connecter	Trance_Paradox	feature	Having both 18650 Holder and connector terminals for li-po battery would provide grea flexibility
47	rejected	Toggle switch to turn on and off boost circuitry		feature	boost circuit takes considerable amount of stand by current (quicient Current). if the user have the option to turn off the boost circuitry by a toggle switch(or simply by a jumper) and use only the 3.3 V from a ldo would be beneficial when working with 3.3 V low power devices.
49	rejected	consider modularity; e.g. having additional boost / display options as hats	johnheuk	feature	to keep base price / complex of basic supply as low as possible. the hats need not physically sit on top of each other or require additional board space but could be connected via 2.54mm dupont pins to keep the basic board as compact as possible
50		Short Circuit Protection on the output	johnheuk	safety	we all know why…… :D
51	rejected	at least the outputs should have 2.54mm jumper pins for quick connection to a breadboard, ideally there should pins and pads for the input, battery and output	johnheuk	feature	pushing modules into a breadboard can be difficult / the user may not have one to hand / they use up a lot of space. for permanent installation, solder pads would be a good idea. this would also allow the user to monitor incoming / storage & outgoing voltages more easily. some people may want to tap into the battery supply itself as batteries typically offer much, much better noise performance
52	rejected	ideally there should be two or three such 2.54mm pins for the output and they should be positioned on opposite sides of the board, not adjacent to one another	johnheuk	feature	the user may want to connect one set to their micro and another to a different module. i have managed to exploderise a breadboard power supply 30 seconds after powering it up after i accidentally shorted the gnd and vcc output header pins checking the voltages with a meter probe - the pins where right next to each other
53		Barrel Jack / Screw Terminals	johnheuk	feature	not everyone has a soldering iron, or one that’s good enough to solder to via stitched ground planes, or may not have a spare usb lead. having a few different connection methods would be great
54	rejected	MPPT (power tracking) / scavange / harvest	johnheuk	power	if the device is trickle charging from a tiny solar cell, having an MPPT type charge controller may be a good idea. could also look into other harvesting methods, e.g. RF, although the power available is likely to be even lower (we can assume that many of these devices will be in range of a standard WiFi router though).
55	rejected	strain relief built into the board; e.g. holes drilled near connection points that the user can loop the wire through and perhaps add some epoxy glue to (not that epoxy really needs to be kept away from copper as it is acid catalysed and can begin to corrode exposed copper	johnheuk	feature	if a squirrel attacks a node the wiring will be less likely to be ripped from the board; fewer pads lifted etc
56	rejected	a hat option to measure Joules of energy consumed; this could be applied to both the esp and pi but would be particularly well suited to the pi	johnheuk	feature	a feature of Texas Instruments’ Code Composer is that it will suggest alterations to code; e.g. use a timer instead of a loop. their MSP430 demo boards go further and can actually monitor real world energy usage when running code, so the user can tune their code and get a better idea of how long the supply will last. this is a feature entirely missing from the esp hat would as far as I’m aware but could be very useful for checking deep sleep type operations. we need to start thinking in terms of Joules per operation / byte sent as opposed to mA
61	rejected	tracking solar panel; additional add on module	johnheuk	feature	if solar is being used, an additional ‘hat’ option could be to have the panel track. given the low power usage requirement, it would likely be better if this was achieved through a system that didn’t include RV servos or steppers being continually engaged. this could possibly be achieved via a 3d printed high gear ratio (so the panel doesn’t move in the breeze even with the power removed) or some form of solenoid like lock on the panel tilt that is normally engaged; so it only energises to move. it may not need to continually track, just point in roughly the right direction at the right time of day (e.g. east in the morning, half way in between at lunch time, west in the evening) to reduce movement frequency. this could be also be achieved by rotating some form of cam or actuating some form of ratchet. this could be particularly useful for higher power applications; like the pi, or more continuous wifi usage via the esp. it should use readily available, generic motion components as opposed to end of line / stock clearance microsteppers
62	rejected	Smallest Board config size 4cm x 3cm	wassfila	dimensions	I input this as initial starting point as stated in the video in time 12:50. It is only to give a guideline for the moment not to deviate too much but given all other requirements this might have to be reconsidered in case some features are really attractive.
63		Expose unused ESP32 GPIO Pins	wassfila	uC	The reference board in the video shows gpio exposed on a header on the sides, and it makes sense that a maker that needs this PCB also wants to use the ESP32 gpios he paid for.
64	rejected	minimal config costs less than 10 €	wassfila	organisation	Given the market where charging modules cost 1 ~ 2€, and ESP boards 5 ~ 8 € including lcd screens : 10 € sounds attractive. Let us place ourself in the buyers side, and think what we would pay for it ? Let’s say this board is special and would be made on demand so maybe 15 €, but if it is 20€ or 30 € would you buy it ?
65	rejected	3d printed case	wassfila	organisation	If this is agreed, it could relax constraints on fitting PCB holes to existing housing standard format as discussed in discord. This could give more flexibility and is today a reasonable expectation from every maker or every one that has a maker as a friend.
66	rejected	Optional Battery format 16340 (16 mm x 34 mm)	wassfila	dimensions	This is mentioned by Andreas in the video time 12:50 and because 18650 is much bigger than an ESP32 module and 16340 fits quite good and matches the size req 62
67	rejected	Operating Temperature range -20° 70°	wassfila	specification	The ESP32 operating range is -40° 125°, but the batteries have more restricted range, so we might save on other compoenents as we don’t need the full range.
68	rejected	Charging Temperature range 0° 45°	wassfila	specification	Charging between 0°-5° might be possible but below 0° might damage the battery. I tool Li-Ion as reference. These could be configurable if it is LifePo.
69	rejected	The design has to be Open source	wassfila	organisation	As stated in the video timing 14:15, I take these requirements here so that they’re visible to everyone even to those who do not remember every word of the video.
70	rejected	It can be manufactured by JLCPCB	wassfila	organisation	same, from the video 14:15
71	rejected	Parts should be availabe from LCSC	wassfila	organisation	same, from the video 14:15
72	rejected	battery ampere meter	wassfila	feature	This would allow used capacity calculation and is different than overcurrent protection. Also stated in the video 15:52 as one reference board had this function, so even if it is hardly feasible, it is worth putting this on the table.
73	rejected	Optional flat battery pack connector	Informatic0re	feature	allows an even more compact size than the 16340 so gives more flexibility
74	rejected	Super Capacitors	Noki		Sensors that don’t require frequent updates could easily be powered from supercaps instead of batteries. Even frequent measurements are not a problem if you store them and only transmit multiple collected measurements together from time to time. Supercaps are easy to charge, are not subject to overcharge and have a good low-temperature charge and discharge performance which makes them great for outdoor usage in cold environements. Supercapacitors don’t require a battery heater, but might require a larger panel to compensate for the higher self discharge.
75	rejected	Parts can be hand soldered	himynameisbuzz		for user who opt not to use a specific function in the board can choose not to solder the parts and to reduce the board’s cost. BGA is a no no
76	rejected	Add PTC Resetable Fuse in design	veilands		Preserve other components due mistakes in assembly and operations, increase reliability of new design
77	rejected	Inclusion of LORA Option	mtroyer	feature	Provision of a low power option for a LORA board such as an RFM95 or the like.
88		Open Hardware License	Noki		We might need to choose a license to open source our hardware properly