Swagbadge2021 Newcomers - Revision history

AndyGelme: /* Electronic circuits */

2021-02-06T05:34:46Z

Electronic circuits

← Older revision		Revision as of 05:34, 6 February 2021
Line 141:		Line 141:
	'''More about resistors'''		'''More about resistors'''

	Resistors come in certain set values. If you can't get the exact value you need, just use the next highest one (don't go lower, or your resistor won't do the job and you'll fry your electronics). You can [https://www.electronics-tutorials.ws/resistor/res_3.html join them together in series] if you want to create a larger resistance (works just like a single resistor of the ~~same~~ value). You can [https://www.electronics-tutorials.ws/resistor/res_4.html join them together in parallel] if you want to create a smaller resistance (also works just like a single resistor of the ~~same~~ value).		Resistors come in certain set values. If you can't get the exact value you need, just use the next highest one (don't go lower, or your resistor won't do the job and you'll fry your electronics). You can [https://www.electronics-tutorials.ws/resistor/res_3.html join them together in series] if you want to create a larger resistance (works just like a single resistor of the equivalent value). You can [https://www.electronics-tutorials.ws/resistor/res_4.html join them together in parallel] if you want to create a smaller resistance (also works just like a single resistor of the equivalent value).

	[https://www.electronics-tutorials.ws/resistor/res_1.html Everything you wanted to know about resistors, but were afraid to ask !]		[https://www.electronics-tutorials.ws/resistor/res_1.html Everything you wanted to know about resistors, but were afraid to ask !]

AndyGelme: /* Electronic circuits */

2021-02-06T05:33:58Z

Electronic circuits

← Older revision		Revision as of 05:33, 6 February 2021
Line 141:		Line 141:
	'''More about resistors'''		'''More about resistors'''

	Resistors come in certain set values. If you can't get the exact value you need, just use the next highest one (don't go lower, or your resistor won't do the job and you'll fry your electronics). You can [https://www.electronics-tutorials.ws/resistor/res_3.html join them together in series] if you want to create a larger resistance (works just like a single resistor or the same value). You can [https://www.electronics-tutorials.ws/resistor/res_4.html join them together in parallel] if you want to create a smaller resistance (also works just like a single resistor of the same value).		Resistors come in certain set values. If you can't get the exact value you need, just use the next highest one (don't go lower, or your resistor won't do the job and you'll fry your electronics). You can [https://www.electronics-tutorials.ws/resistor/res_3.html join them together in series] if you want to create a larger resistance (works just like a single resistor of the same value). You can [https://www.electronics-tutorials.ws/resistor/res_4.html join them together in parallel] if you want to create a smaller resistance (also works just like a single resistor of the same value).

	[https://www.electronics-tutorials.ws/resistor/res_1.html Everything you wanted to know about resistors, but were afraid to ask !]		[https://www.electronics-tutorials.ws/resistor/res_1.html Everything you wanted to know about resistors, but were afraid to ask !]

AndyGelme: /* Electronic circuits */

2021-02-06T05:33:23Z

Electronic circuits

← Older revision		Revision as of 05:33, 6 February 2021
Line 128:		Line 128:

	LEDs have complicated behavior that affects our use of Ohm's Law, so we have to do a bit more to get the values right. For LEDs, the important thing is the voltage drop across the LED. This can also be known as the forward voltage.		LEDs have complicated behavior that affects our use of Ohm's Law, so we have to do a bit more to get the values right. For LEDs, the important thing is the voltage drop across the LED. This can also be known as the forward voltage.
	* ~~It's~~ still R = V / I, but ~~allowing~~ for how we calculate the ~~voltage~~ requirements for an LED: Required resistor = (~~battery source~~ voltage - LED voltage drop) / ~~desired~~ current		* LEDs have static resistance and our circuit will still obey R = V / I, but let's adjust for how we calculate the current limiting requirements for an LED as follows: Required resistor = (Power voltage - LED voltage drop) / Desired maximum current

	Quick example:		Quick example:

AndyGelme: /* Electronic circuits */

2021-02-06T05:30:37Z

Electronic circuits

← Older revision		Revision as of 05:30, 6 February 2021
Line 123:		Line 123:
	Note: Often the eThingy will have a voltage potential across them too, reducing the voltage potential across the resistor in the calculation above. See LEDs below		Note: Often the eThingy will have a voltage potential across them too, reducing the voltage potential across the resistor in the calculation above. See LEDs below

	Usually, the resistor can be placed on either side of the component ... either between power and the component ... or the ground and the component. In either case, the resistor is limiting the current flow just fine.		Usually, the resistor can be placed on either side of the component ... either between power and the component ... or the ground and the component. In either case, the resistor is limiting the current flow just fine. However, to keep things simple and consistent, it is recommended to make the "ground" our shared base for everything and achieve this by putting the current limiting resistor between power and the component.

	'''LEDs are special, because they do not act like pure resistors'''		'''LEDs are special, because they do not act like pure resistors'''

AndyGelme: /* Electronic circuits */

2021-02-06T05:26:17Z

Electronic circuits

← Older revision		Revision as of 05:26, 6 February 2021
Line 89:		Line 89:
	[[File:Lolin32_lite_schematic.gif\|480px]]		[[File:Lolin32_lite_schematic.gif\|480px]]

	In order for components to work, they need a power source (typically for the SwagBadge that's a USB cable providing 5 volts [https://en.wikipedia.org/wiki/Direct_current direct-current]), they need a [https://en.wikipedia.org/wiki/Ground_(electricity) ground] (also on the board), and the ~~component(s) sits~~ between the power and the ground. But you can't just plug in any old component into any old power source. Things can go wrong:		In order for components to work, they need a power source (typically for the SwagBadge that's a USB cable providing 5 volts [https://en.wikipedia.org/wiki/Direct_current direct-current]), they need a [https://en.wikipedia.org/wiki/Ground_(electricity) ground] (also on the board), and the components sit between the power and the ground. But you can't just plug in any old component into any old power source. Things can go wrong:
	* Too much power for a component can fry it and let out the [https://en.wikipedia.org/wiki/Magic_smoke magic smoke].		* Too much power for a component can fry it and let out the [https://en.wikipedia.org/wiki/Magic_smoke magic smoke].
	* Not enough power and your component just won't work. In an attempt to get enough power, it may even fry your badge's power source - if it's powered via USB to your laptop, this may mean doing Bad Things to your USB port or your laptop.		* Not enough power and your component just won't work. In an attempt to get enough power, it may even fry your badge's power source - if it's powered via USB to your laptop, this may mean doing Bad Things to your USB port or your laptop.

AndyGelme: /* Electronic circuits */

2021-02-06T05:25:36Z

Electronic circuits

← Older revision		Revision as of 05:25, 6 February 2021
Line 92:		Line 92:
	* Too much power for a component can fry it and let out the [https://en.wikipedia.org/wiki/Magic_smoke magic smoke].		* Too much power for a component can fry it and let out the [https://en.wikipedia.org/wiki/Magic_smoke magic smoke].
	* Not enough power and your component just won't work. In an attempt to get enough power, it may even fry your badge's power source - if it's powered via USB to your laptop, this may mean doing Bad Things to your USB port or your laptop.		* Not enough power and your component just won't work. In an attempt to get enough power, it may even fry your badge's power source - if it's powered via USB to your laptop, this may mean doing Bad Things to your USB port or your laptop.

	You can think of electronics components as analogous to software functions ... there are input(s), output(s) and some shenanigans occur in-between ! This is great, because you can largely forget about the whole SwagBadge circuit and focus on just the SAO connector's inputs and outputs, e.g 3.3V power, ground, I2C (clock and data pins) and two General Purpose Input / Output (GPIO) pins. Too easy !

	Whilst the USB cable provides 5 volts (and an optional LiPo battery provides around 3.7 volts), everything (including the SAOs) beyond the USB cable and voltage regulator is '''powered by 3.3 volts'''. Many of the components may be damaged by exposing them to greater than 3.6 volts (3.3 volt rating plus 10%). It is also very important to not accidentally swap power and ground (connect ground to the power lines and the power to the ground lines), which may also damage components.		Whilst the USB cable provides 5 volts (and an optional LiPo battery provides around 3.7 volts), everything (including the SAOs) beyond the USB cable and voltage regulator is '''powered by 3.3 volts'''. Many of the components may be damaged by exposing them to greater than 3.6 volts (3.3 volt rating plus 10%). It is also very important to not accidentally swap power and ground (connect ground to the power lines and the power to the ground lines), which may also damage components.

	The role of the voltage regulator is to reduce the power supply voltage (from 5 volts) to the 3.3 volts required by the SwagBadge circuitry and components. Looking closely at the schematic diagram at '''''U4: ME6211''''' (top, middle), you can see that the inputs are <VBUS> (USB cable power), <VBAT> (LiPo battery power) and <GND> (the ground) ... and that the outputs are <+3V3> (3.3 volts) and <GND> (not strictly an output, but for the sake of modularity, let's pretend). Throughout the schematic, many components have an "arrow" pointing towards <+3V3>, which simply means "connected to", in this schematic diagram the arrow does not indicate "flow of elections" or anything like that.		The role of the voltage regulator is to reduce the power supply voltage (from 5 volts) to the 3.3 volts required by the SwagBadge circuitry and components. Looking closely at the schematic diagram at '''''U4: ME6211''''' (top, middle), you can see that the inputs are <VBUS> (USB cable power), <VBAT> (LiPo battery power) and <GND> (the ground) ... and that the outputs are <+3V3> (3.3 volts) and <GND> (not strictly an output, but for the sake of modularity, let's pretend). Throughout the schematic, many components have an "arrow" pointing towards <+3V3>, which simply means "connected to", in this schematic diagram the arrow does not indicate "flow of elections" or anything like that.

			You can think of electronics components as analogous to software functions ... there are input(s), output(s) and some shenanigans occur in-between ! This is great, because you can largely forget about the whole SwagBadge circuit and focus on just the SAO connector's inputs and outputs, e.g 3.3V power, ground, I2C (clock and data pins) and two General Purpose Input / Output (GPIO) pins. Too easy !

	'''Getting the power requirements right'''		'''Getting the power requirements right'''

AndyGelme: /* Electronic circuits */

2021-02-06T05:24:53Z

Electronic circuits

← Older revision		Revision as of 05:24, 6 February 2021
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	* Not enough power and your component just won't work. In an attempt to get enough power, it may even fry your badge's power source - if it's powered via USB to your laptop, this may mean doing Bad Things to your USB port or your laptop.		* Not enough power and your component just won't work. In an attempt to get enough power, it may even fry your badge's power source - if it's powered via USB to your laptop, this may mean doing Bad Things to your USB port or your laptop.

	You can think of electronics components as analogous to software functions ... there are input(s), output(s) and some shenanigans occur in-between !		You can think of electronics components as analogous to software functions ... there are input(s), output(s) and some shenanigans occur in-between ! This is great, because you can largely forget about the whole SwagBadge circuit and focus on just the SAO connector's inputs and outputs, e.g 3.3V power, ground, I2C (clock and data pins) and two General Purpose Input / Output (GPIO) pins. Too easy !

	Whilst the USB cable provides 5 volts (and an optional LiPo battery provides around 3.7 volts), everything (including the SAOs) beyond the USB cable and voltage regulator is '''powered by 3.3 volts'''. Many of the components may be damaged by exposing them to greater than 3.6 volts (3.3 volt rating plus 10%). It is also very important to not accidentally swap power and ground (connect ground to the power lines and the power to the ground lines), which may also damage components.		Whilst the USB cable provides 5 volts (and an optional LiPo battery provides around 3.7 volts), everything (including the SAOs) beyond the USB cable and voltage regulator is '''powered by 3.3 volts'''. Many of the components may be damaged by exposing them to greater than 3.6 volts (3.3 volt rating plus 10%). It is also very important to not accidentally swap power and ground (connect ground to the power lines and the power to the ground lines), which may also damage components.

AndyGelme: /* Electronic circuits */

2021-02-06T05:11:44Z

Electronic circuits

← Older revision		Revision as of 05:11, 6 February 2021
Line 125:		Line 125:
	Usually, the resistor can be placed on either side of the component ... either between power and the component ... or the ground and the component. In either case, the resistor is limiting the current flow just fine.		Usually, the resistor can be placed on either side of the component ... either between power and the component ... or the ground and the component. In either case, the resistor is limiting the current flow just fine.

	'''LEDs are special, because they ~~are active (~~not ~~passive) components~~'''		'''LEDs are special, because they do not act like pure resistors'''

	LEDs have ~~a twist~~ that affects our use of Ohm's Law, so we have to do a bit more to get the values right. For LEDs the important thing is the voltage drop across the LED. This can also be known as the forward voltage.		LEDs have complicated behavior that affects our use of Ohm's Law, so we have to do a bit more to get the values right. For LEDs, the important thing is the voltage drop across the LED. This can also be known as the forward voltage.
	* It's still R = V / I, but allowing for how we calculate the voltage requirements for ~~a led~~: R = (battery source voltage - LED voltage drop) / current		* It's still R = V / I, but allowing for how we calculate the voltage requirements for an LED: Required resistor = (battery source voltage - LED voltage drop) / desired current

	Quick example:		Quick example:
	* If you have a ''red'' LED with a voltage drop/forward voltage of 2V, and maximum current requirement of 20 mA (milliamps)		* If you have a ''red'' LED with a voltage drop/forward voltage of 2V, and maximum current requirement of 20 mA (milliamps)
	* ~~Voltage off~~ the badge is 5V		* Power voltage on the badge is 3.3V
	* R = (3.3 - 2) / .02 = 65		* R = (3.3 - 2) / .02 = 65
	* We need a 65 ohm resistor		* We need a 65 ohm resistor
	* A 65 ohm resistor will provide maximum brightness, larger resistor values, e.g 1,000 ohms will limit the current further and delivery a dimmer LED experience		* A 65 ohm resistor will provide maximum brightness and larger resistor values, e.g 1,000 ohms will limit the current further and delivery a dimmer LED experience

	Note: Different colour LEDs will have different forward voltage drops. For a given colour, e.g red, there will be a small range of forward voltage drops, e.g 1.7V to 2.0V.		Note: Different colour LEDs will have different forward voltage drops. For a given colour, e.g red, there will be a small range of forward voltage drops, e.g 1.7V to 2.0V.

AndyGelme: Electronics circuits: Review, corrections (3.3V) and updates

2021-02-06T04:40:47Z

Electronics circuits: Review, corrections (3.3V) and updates

← Older revision		Revision as of 04:40, 6 February 2021
Line 77:		Line 77:
	=== Electronic circuits ===		=== Electronic circuits ===

	Itching to add some blinky lights to a SAO~~, whip~~ out that soldering iron and ~~get~~ to work? Let's first talk about circuitry.		Itching to add some blinky lights to a SAO ... by whipping out that soldering iron and getting to work ? Let's first talk about [https://en.wikipedia.org/wiki/Electronic_circuit circuitry].

	In order for components to work, they need a power source (~~in our case,~~ that's a 5 ~~Volt DC feed off the badge, coming through the SAO headers and onto our protoboard~~), they need a ground (also on the board), and the component(s) sits between the power and the ground. But you can't just plug in any old component into any old power source. Things can go wrong:		It is very difficult to think about, design, repair or discuss something unless you have a clear picture (model) in your mind. This is especially true of electronics, because without tools (a simple LED, multimeter, oscilloscope, logic analyzer or scanning tunneling microscope) we just can't see electrons. Knowing how the electrons flow through circuits within your SwagBadge is one of the crucial keys to understanding. Fortunately, you can approach this problem in simple steps ... well, ''"simple"'' if you have good guidance. [https://spectrum.chat/lca2021-swagbadge/hardware?tab=posts Please feel free to ask the OHMC team on the SwagBadge Spectrum forum] !

			''<ToDo: Start with high-level diagram before diving in deeper !>''

			Let's dive in the deep end by briefly checking out a '''''[https://en.wikipedia.org/wiki/Schematic schematic diagram] (pictured below)'''''. There are lots of unfamiliar symbols and terminology, but in essence it is like a map. A map that shows what components exist in the circuit and how they are connected together, from which we can determine how electricity (electrons) flows to encode data and changes to that data.

			''Note: The [https://en.wikipedia.org/wiki/Voltage_regulator voltage regulator] discussed soon is in the top-middle of the diagram with a part labelled '''U4: ME6211'''''

			[[File:Lolin32_lite_schematic.gif\|480px]]

			In order for components to work, they need a power source (typically for the SwagBadge that's a USB cable providing 5 volts [https://en.wikipedia.org/wiki/Direct_current direct-current]), they need a [https://en.wikipedia.org/wiki/Ground_(electricity) ground] (also on the board), and the component(s) sits between the power and the ground. But you can't just plug in any old component into any old power source. Things can go wrong:
	* Too much power for a component can fry it and let out the [https://en.wikipedia.org/wiki/Magic_smoke magic smoke].		* Too much power for a component can fry it and let out the [https://en.wikipedia.org/wiki/Magic_smoke magic smoke].
	* Not enough power and your component just won't work. In an attempt to get enough power, it may even fry your badge's power source - if it's powered via USB to your laptop, this may mean doing Bad Things to your USB port or your laptop.		* Not enough power and your component just won't work. In an attempt to get enough power, it may even fry your badge's power source - if it's powered via USB to your laptop, this may mean doing Bad Things to your USB port or your laptop.

			You can think of electronics components as analogous to software functions ... there are input(s), output(s) and some shenanigans occur in-between !

			Whilst the USB cable provides 5 volts (and an optional LiPo battery provides around 3.7 volts), everything (including the SAOs) beyond the USB cable and voltage regulator is '''powered by 3.3 volts'''. Many of the components may be damaged by exposing them to greater than 3.6 volts (3.3 volt rating plus 10%). It is also very important to not accidentally swap power and ground (connect ground to the power lines and the power to the ground lines), which may also damage components.

			The role of the voltage regulator is to reduce the power supply voltage (from 5 volts) to the 3.3 volts required by the SwagBadge circuitry and components. Looking closely at the schematic diagram at '''''U4: ME6211''''' (top, middle), you can see that the inputs are <VBUS> (USB cable power), <VBAT> (LiPo battery power) and <GND> (the ground) ... and that the outputs are <+3V3> (3.3 volts) and <GND> (not strictly an output, but for the sake of modularity, let's pretend). Throughout the schematic, many components have an "arrow" pointing towards <+3V3>, which simply means "connected to", in this schematic diagram the arrow does not indicate "flow of elections" or anything like that.

	'''Getting the power requirements right'''		'''Getting the power requirements right'''

	# ~~work~~ out what the power consumption requirements are for your components		# Work out what the power consumption requirements are for your components, for both voltage and current
	# If it's more than what your power source provides, you'd better get a bigger power source/battery and hook up the power to that, and not to the badge.		# If it's more than what your power source provides, you'd better get a bigger power source/battery and hook up the power to that, and not to the badge
	# If it's less than what your power source provides, you'll need some resistors to reduce the load going through your components.		# If it's less than what your power source provides, you'll need some resistors* to reduce the load going through your components

			Note: Using resistors works for [https://www.power-and-beyond.com/introduction-to-electronic-compontents-active-vs-passive-components-a-893768/ passive components, however some active components] may need a different approach to limiting current through them

	'''It's just maths'''		'''It's just maths'''
Line 93:		Line 111:
	[https://learn.sparkfun.com/tutorials/voltage-current-resistance-and-ohms-law/all Ohm's Law] is our guide. V = I x R. Voltage (V) = Current in amps (I) x Resistance in ohms (R).		[https://learn.sparkfun.com/tutorials/voltage-current-resistance-and-ohms-law/all Ohm's Law] is our guide. V = I x R. Voltage (V) = Current in amps (I) x Resistance in ohms (R).

	We know our badge gives you 5V.		'''We know our badge gives you 3.3V'''

	You can determine the current requirements of your components by looking at their data sheets. Some will have a maximum current rating (you must stay below this!) and a recommended current rating (what you're aiming to meet).		You can determine the current requirements of your components by looking at their data sheets. Some will have a maximum current rating (you must stay below this !) and a recommended current rating (what you're aiming to meet).

	Quick example:		Quick example:
	* Let's say you have an eThingy that has a recommended current rating of 5 milliamps.		* Let's say you have an eThingy that has a recommended current rating of 20 milliamps
	* Voltage off the badge is 5V		* Voltage off the badge is 3.3V
	* We use Ohm's ~~law~~ to calculate the resistance (R = V / I), in our case, V=5, I = 0.05. So R= 5 / 0.05 = ~~100~~		* We use Ohm's Law to calculate the resistance (R = V / I), in our case, V = 3.3, I = 0.02 ... so R = 3.3 / 0.02 = 165
	* We need to use a ~~100~~ ohm resistor.		* We need to use a 165 ohm resistor

			Note: Often the eThingy will have a voltage potential across them too, reducing the voltage potential across the resistor in the calculation above. See LEDs below

	~~The~~ resistor ~~always goes~~ between ~~the~~ power ~~source~~ and the component. ~~(don't put it between~~ component ~~and ground: it's too late by then!)~~		Usually, the resistor can be placed on either side of the component ... either between power and the component ... or the ground and the component. In either case, the resistor is limiting the current flow just fine.

	'''LEDs are special.'''		'''LEDs are special, because they are active (not passive) components'''

	LEDs ~~break~~ Ohm's ~~law~~, so we have to do a bit more to get the values right. For LEDs the important thing is the voltage drop across the LED. This can also be known as the forward voltage.		LEDs have a twist that affects our use of Ohm's Law, so we have to do a bit more to get the values right. For LEDs the important thing is the voltage drop across the LED. This can also be known as the forward voltage.
	* It's still R = V / I, but allowing for how we calculate the voltage requirements for a led: R = (battery source voltage - LED voltage drop) / current		* It's still R = V / I, but allowing for how we calculate the voltage requirements for a led: R = (battery source voltage - LED voltage drop) / current

	Quick example:		Quick example:
	* If you have a LED with a voltage drop/forward voltage of 2V, and current requirement of ~~20mA~~ (milliamps)		* If you have a ''red'' LED with a voltage drop/forward voltage of 2V, and maximum current requirement of 20 mA (milliamps)
	* Voltage off the badge is 5V		* Voltage off the badge is 5V
	* R = (5 - 2) / .02 = ~~150~~		* R = (3.3 - 2) / .02 = 65
	* We need a ~~150~~ ohm resistor.		* We need a 65 ohm resistor
			* A 65 ohm resistor will provide maximum brightness, larger resistor values, e.g 1,000 ohms will limit the current further and delivery a dimmer LED experience

			Note: Different colour LEDs will have different forward voltage drops. For a given colour, e.g red, there will be a small range of forward voltage drops, e.g 1.7V to 2.0V.

	'''More about resistors'''		'''More about resistors'''

	Resistors come in certain set values. If you can't get the exact value you need, just use the next highest one (don't go lower, or your resistor won't do the job and you'll fry your electronics). You can join them together in series if you ~~have~~ to.		Resistors come in certain set values. If you can't get the exact value you need, just use the next highest one (don't go lower, or your resistor won't do the job and you'll fry your electronics). You can [https://www.electronics-tutorials.ws/resistor/res_3.html join them together in series] if you want to create a larger resistance (works just like a single resistor or the same value). You can [https://www.electronics-tutorials.ws/resistor/res_4.html join them together in parallel] if you want to create a smaller resistance (also works just like a single resistor of the same value).

			[https://www.electronics-tutorials.ws/resistor/res_1.html Everything you wanted to know about resistors, but were afraid to ask !]

	'''Series vs parallel'''		'''Series vs parallel'''

Nicola: /* All about SAOs: Simple Add Ons */

2021-02-05T01:46:23Z

All about SAOs: Simple Add Ons

@@ Line 79: / Line 79: @@
 Itching to add some blinky lights to a SAO, whip out that soldering iron and get to work? Let's first talk about circuitry.
-In order for components to work, they need a power source (in our case, that's a 3.3 volt DC feed off the badge, coming through the SAO headers and onto our protoboard), they need a ground (also on the board), and the component(s) sits between the power and the ground. But you can't just plug in any old component into any old power source. Things can go wrong:
+In order for components to work, they need a power source (in our case, that's a 5 Volt DC feed off the badge, coming through the SAO headers and onto our protoboard), they need a ground (also on the board), and the component(s) sits between the power and the ground. But you can't just plug in any old component into any old power source. Things can go wrong:
 * Too much power for a component can fry it and let out the [https://en.wikipedia.org/wiki/Magic_smoke magic smoke].
 * Not enough power and your component just won't work. In an attempt to get enough power, it may even fry your badge's power source - if it's powered via USB to your laptop, this may mean doing Bad Things to your USB port or your laptop.