SolarBatLight - Revision history

Bertrik Sikken: Update project status

2014-08-08T13:01:19Z

Update project status

← Older revision		Revision as of 13:01, 8 August 2014
Line 1:		Line 1:
	{{Project		{{Project
	\|Name=SolarBatLight		\|Name=SolarBatLight
	\|Status=~~In progress~~		\|Status=Stalled
	\|Contact=bertrik		\|Contact=bertrik
	}}		}}

			Status: need to design a pre-amplifier and detection circuit, not entirely convinced that enough power can be supplied for a good light effect.

	== Introduction ==		== Introduction ==

Bertrik Sikken at 15:15, 16 June 2014

2014-06-16T15:15:00Z

← Older revision		Revision as of 15:15, 16 June 2014
Line 60:		Line 60:

	Garden light measurement results:		Garden light measurement results:
			* I've tried various other LEDs, the original one is pretty bright already.
	* The LED gets about 3.1V peak		* The LED gets about 3.1V peak
	* the step-up frequency (with the LED connected) is about 145 kHz		* the step-up frequency (with the LED connected) is about 145 kHz
Line 65:		Line 66:
	* the boost circuit appears to work in continuous mode, the 40%/60% charge/discharge times correspond nicely with the 1.2V charge and 1.8V discharge voltages.		* the boost circuit appears to work in continuous mode, the 40%/60% charge/discharge times correspond nicely with the 1.2V charge and 1.8V discharge voltages.
	* it is estimated that on average, the LED receives half the peak coil current, or about 7.5 mA. At 3V average voltage, this means an average power of 9 mW.		* it is estimated that on average, the LED receives half the peak coil current, or about 7.5 mA. At 3V average voltage, this means an average power of 9 mW.


	[[File:IMAG0525.jpg\|right\|300px]]		[[File:IMAG0525.jpg\|right\|300px]]
	HC-SR04 measurement results:		HC-SR04 measurement results:
	* I've tried various other LEDs, the original one is pretty bright already.
	* At the output of the final amplification stage (at pin 7 of the LM324/TL074, just before comparison with the reference level), the signal output is about 100 mV (keys rattling in front of the microphone).		* At the output of the final amplification stage (at pin 7 of the LM324/TL074, just before comparison with the reference level), the signal output is about 100 mV (keys rattling in front of the microphone).
	* From looking at the comparator part of the schematic, I derive that the final reference level sits at 2.41V. Compared to the average signal level of 2.5V (1/2Vcc), this means that a signal of about 88 mV amplitude causes a signal to go to the microcontroller.		* From looking at the comparator part of the schematic, I derive that the final reference level sits at 2.41V. Compared to the average signal level of 2.5V (1/2Vcc), this means that a signal of about 88 mV amplitude causes a signal to go to the microcontroller.

Bertrik Sikken at 15:13, 16 June 2014

2014-06-16T15:13:49Z

← Older revision		Revision as of 15:13, 16 June 2014
Line 22:		Line 22:
	* detect day or night by looking at the output of the solar array		* detect day or night by looking at the output of the solar array
	* during the day, charge a battery (typically single cell AA NiMH) from the solar array		* during the day, charge a battery (typically single cell AA NiMH) from the solar array
	* during the night, step-up the voltage of the battery (about 1.3V) to a voltage that the LED needs (about ~~3.5V~~)		* during the night, step-up the voltage of the battery (about 1.2V) to a voltage that the LED needs (about 3V)

	It does this using a surprisingly simple circuit, similar to a so-called joule-thief.		It does this using a surprisingly simple circuit, similar to a so-called joule-thief.
Line 62:		Line 62:
	* The LED gets about 3.1V peak		* The LED gets about 3.1V peak
	* the step-up frequency (with the LED connected) is about 145 kHz		* the step-up frequency (with the LED connected) is about 145 kHz
			* the coil is charged for approximately 4.1 us, with an inductance of about 330 uH, this means about 15 mA peak through the coil.
			* the boost circuit appears to work in continuous mode, the 40%/60% charge/discharge times correspond nicely with the 1.2V charge and 1.8V discharge voltages.
			* it is estimated that on average, the LED receives half the peak coil current, or about 7.5 mA. At 3V average voltage, this means an average power of 9 mW.

	[[File:IMAG0525.jpg\|right\|300px]]		[[File:IMAG0525.jpg\|right\|300px]]

Bertrik Sikken: plaatje van elektronica in tuinlampje

2014-06-07T12:06:26Z

plaatje van elektronica in tuinlampje

← Older revision		Revision as of 12:06, 7 June 2014
Line 17:		Line 17:

	== Inside a garden light ==		== Inside a garden light ==
			[[File:cl0116.jpg\|right\|200px]]

	A typical inexpensive (3 EUR) garden light combines the following functions:		A typical inexpensive (3 EUR) garden light combines the following functions:
	* detect day or night by looking at the output of the solar array		* detect day or night by looking at the output of the solar array

Bertrik Sikken: Update project status

2014-06-01T22:18:07Z

Update project status

← Older revision		Revision as of 22:18, 1 June 2014
Line 1:		Line 1:
	{{Project		{{Project
	\|Name=SolarBatLight		\|Name=SolarBatLight
	\|Status=~~Initializing~~		\|Status=In progress
	\|Contact=bertrik		\|Contact=bertrik
	}}		}}

Bertrik Sikken at 22:17, 1 June 2014

2014-06-01T22:17:24Z

← Older revision		Revision as of 22:17, 1 June 2014
Line 48:		Line 48:
	== Experimentation ==		== Experimentation ==
	[[File:IMAG0524.jpg\|right\|300px]]		[[File:IMAG0524.jpg\|right\|300px]]

	I should find out the following things:		I should find out the following things:
	* How much voltage/current can the step-up circuit of the garden light deliver?		* How much voltage/current can the step-up circuit of the garden light deliver?
Line 57:		Line 56:
	* Does the whole thing actually work on real bats? (like pipistrellus pipistrellus or "dwergvleermuis" in the netherlands).		* Does the whole thing actually work on real bats? (like pipistrellus pipistrellus or "dwergvleermuis" in the netherlands).

	~~[[File:IMAG0525.jpg\|right\|300px]]~~
	~~Results~~:		Garden light measurement results:
	* The LED gets about 3.1V peak		* The LED gets about 3.1V peak
	* the step-up frequency (with the LED connected) is about 145 kHz		* the step-up frequency (with the LED connected) is about 145 kHz


			[[File:IMAG0525.jpg\|right\|300px]]
			HC-SR04 measurement results:
	* I've tried various other LEDs, the original one is pretty bright already.		* I've tried various other LEDs, the original one is pretty bright already.
	* At the output of the final amplification stage (at pin 7 of the LM324/TL074, just before comparison with the reference level), the signal output is about 100 mV (keys rattling in front of the microphone).		* At the output of the final amplification stage (at pin 7 of the LM324/TL074, just before comparison with the reference level), the signal output is about 100 mV (keys rattling in front of the microphone).
Line 75:		Line 78:

	== Silly ideas ==		== Silly ideas ==
	~~Some silly ideas~~
	=== Triangulation ===		=== Triangulation ===
	* put an arduino (like the pro mini, 3 EUR) + inexpensive wireless receiver (like the NRF24L01+, 1 EUR) in each of the garden lights and make it run an ad-hoc wireless network		* put an arduino (like the pro mini, 3 EUR) + inexpensive wireless receiver (like the NRF24L01+, 1 EUR) in each of the garden lights and make it run an ad-hoc wireless network

Bertrik Sikken at 22:13, 1 June 2014

2014-06-01T22:13:32Z

← Older revision		Revision as of 22:13, 1 June 2014
Line 46:		Line 46:
	* use the existing digital output to drive a LED		* use the existing digital output to drive a LED

	== ~~Experiment~~ ==		== Experimentation ==
	[[File:IMAG0524.jpg\|right\|300px]]		[[File:IMAG0524.jpg\|right\|300px]]

Line 57:		Line 57:
	* Does the whole thing actually work on real bats? (like pipistrellus pipistrellus or "dwergvleermuis" in the netherlands).		* Does the whole thing actually work on real bats? (like pipistrellus pipistrellus or "dwergvleermuis" in the netherlands).

			[[File:IMAG0525.jpg\|right\|300px]]
	Results:		Results:
	* The LED gets about 3.1V peak		* The LED gets about 3.1V peak
Line 63:		Line 64:
	* At the output of the final amplification stage (at pin 7 of the LM324/TL074, just before comparison with the reference level), the signal output is about 100 mV (keys rattling in front of the microphone).		* At the output of the final amplification stage (at pin 7 of the LM324/TL074, just before comparison with the reference level), the signal output is about 100 mV (keys rattling in front of the microphone).
	* From looking at the comparator part of the schematic, I derive that the final reference level sits at 2.41V. Compared to the average signal level of 2.5V (1/2Vcc), this means that a signal of about 88 mV amplitude causes a signal to go to the microcontroller.		* From looking at the comparator part of the schematic, I derive that the final reference level sits at 2.41V. Compared to the average signal level of 2.5V (1/2Vcc), this means that a signal of about 88 mV amplitude causes a signal to go to the microcontroller.
			* The scope image on the right shows the signal going into the microcontroller, with the reference level at its most sensitive setting (pin 10 cut). They're rather short positive spikes, one for each time the signal crosses the reference level.

	=== LED power ===		=== LED power ===

Bertrik Sikken at 21:56, 1 June 2014

2014-06-01T21:56:16Z

← Older revision		Revision as of 21:56, 1 June 2014
Line 61:		Line 61:
	* the step-up frequency (with the LED connected) is about 145 kHz		* the step-up frequency (with the LED connected) is about 145 kHz
	* I've tried various other LEDs, the original one is pretty bright already.		* I've tried various other LEDs, the original one is pretty bright already.
			* At the output of the final amplification stage (at pin 7 of the LM324/TL074, just before comparison with the reference level), the signal output is about 100 mV (keys rattling in front of the microphone).
			* From looking at the comparator part of the schematic, I derive that the final reference level sits at 2.41V. Compared to the average signal level of 2.5V (1/2Vcc), this means that a signal of about 88 mV amplitude causes a signal to go to the microcontroller.

	=== LED power ===		=== LED power ===

Bertrik Sikken at 16:37, 1 June 2014

2014-06-01T16:37:49Z

← Older revision		Revision as of 16:37, 1 June 2014
Line 37:		Line 37:
	* on the receive side, a TL074/LM324 quad opamp is used to amplify the received echo signal		* on the receive side, a TL074/LM324 quad opamp is used to amplify the received echo signal
	* the first three opamp stages are used to amplify, band-pass filter, amplify respectively		* the first three opamp stages are used to amplify, band-pass filter, amplify respectively
	* the first two stages of the TL074 amplify the signal by about 5x and 10x respectively
	* the last stage compares the received signal to a reference level to determine when an echo is actually received (doing a clever trick, making it more sensitive as time goes by and no echo has been received yet)		* the last stage compares the received signal to a reference level to determine when an echo is actually received (doing a clever trick, making it more sensitive as time goes by and no echo has been received yet)

Bertrik Sikken at 09:47, 1 June 2014

2014-06-01T09:47:29Z

← Older revision		Revision as of 09:47, 1 June 2014
Line 35:		Line 35:
	* a small microcontroller on the module controls the timing of the pulse that is sent		* a small microcontroller on the module controls the timing of the pulse that is sent
	* an RS232 level-converter boosts the pulse waveform to about +10 and -10V for a strong signal into the transmitter transducer		* an RS232 level-converter boosts the pulse waveform to about +10 and -10V for a strong signal into the transmitter transducer
	* on the receive side, a TL074 quad opamp is used to amplify the received echo signal		* on the receive side, a TL074/LM324 quad opamp is used to amplify the received echo signal
			* the first three opamp stages are used to amplify, band-pass filter, amplify respectively
	* the first two stages of the TL074 amplify the signal by about 5x and 10x respectively		* the first two stages of the TL074 amplify the signal by about 5x and 10x respectively
	* the last ~~two stages compare~~ the received signal to a reference level to determine when an echo is actually received (doing a clever trick, making it more sensitive as time goes by and no echo has been received yet)		* the last stage compares the received signal to a reference level to determine when an echo is actually received (doing a clever trick, making it more sensitive as time goes by and no echo has been received yet)

	The ~~mod~~ to the module will probably consist of the following:		There's a very nice analysis and schematic of the circuit at [http://uglyduck.ath.cx/ep/archive/2014/01/Making_a_better_HC_SR04_Echo_Locator.html Emil's projects].

			The modifications to the module will probably consist of the following:
	* to save power, disable (or remove) the transmit logic, i.e. the microcontroller and the RS232 level converter		* to save power, disable (or remove) the transmit logic, i.e. the microcontroller and the RS232 level converter
	* set a fixed reference level instead of one that is variable with time		* set a fixed reference level instead of one that is variable with time