A lot wasn’t known but they went anyway

Armstrong and Aldrin did their own test. Just a moment after he became the first human being to step onto the Moon, Armstrong had scooped a bit of lunar dirt into a sample bag and put it in a pocket of his spacesuit—a contingency sample, in the event the astronauts had to leave suddenly without collecting rocks. Back inside the lunar module the duo opened the bag and spread the lunar soil on top of the ascent engine. As they repressurized the cabin, they watched to see if the dirt started to smolder. “If it did, we’d stop pressurization, open the hatch and toss it out,” Aldrin explained. “But nothing happened.”

Watch App Design

Winning strategies for wearables. If you’re considering a move into wearables, here are a few recommendations:

  • Tech fit for the real world – Consider how to best marry amazing technical capabilities with people’s real-world habits and desires.
  • Understand needs – Ensure you know who you’re designing the wearables for, and what their needs and desires are.
  • Sharp focus – Prioritize ruthlessly around your core service and its core benefit, your wearable device will inevitably die if it contracts featuritis.
  • Segment functionality – As wearables should be small, carefully consider what’s best done and seen on the device itself, and what can be “delegated” to a smartphone.
  • Make the experience desirable and stylish – As Bill Geiser of MetaWatch says, “we carry devices but we wear fashion.”
  • Know the data core – Obsess about the hardware, but obsess even more about the smart data service enabled by the technology. The gadget is merely the keyhole into a kingdom of interconnected data.
  • Data fluidity – Allow users’ data to move fluidly between devices and be freely exported and aggregated, as users will get more benefit from solutions that can be compared and mashed up.
  • Design for the glance – Ensure a simple glance at the device can provide information and value.
  • Have fun inventing – The category needs leadership. Follow the advice of legendary inventor and designer Buckminster Fuller, who said “The best way to predict the future is to design it.”
  • _________________________________
  • Elegance and simplicity are core attributes of the quarter-sized activity tracker Misfit Shine, yet it can be used flexibly for several different activities and situations.
  • Scales by Withings piggyback cleverly on an existing daily ritual – weighing oneself – rather than trying to introduce completely new digital rituals.
  • The Fjord-designed smartphone app Macaw aggregates data from several sources in one experience, allowing users to get an overview of various things they track.
  • Category pioneers FitBit have long been known for reliable and accurate data, which is a foundation for trust.
  • Excellent design drivers around glanceability and “hands freedom” guide smart watch pioneers MetaWatch.

ESP32 Sample Service

        // SampleBuffferInitI2S
	// Do the initial setup required if we're going to capture the audio with I2S

	//i2s number
	#define EXAMPLE_I2S_NUM           (I2S_NUM_0)
	//i2s sample rate
	//enable display buffer for debug
	#define EXAMPLE_I2S_BUF_DEBUG     (0)
	//I2S read buffer length
	//I2S built-in ADC unit
	#define I2S_ADC_UNIT              ADC_UNIT_1
	//I2S built-in ADC channel
	#define I2S_ADC_CHANNEL           ADC1_CHANNEL_0

	//flash record size, for recording 5 second
	void SampleBufferInitI2S()
		i2s_config_t i2s_config;
		i2s_config.mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX | I2S_MODE_ADC_BUILT_IN);
    	        i2s_config.sample_rate = SAMPLING_FREQUENCY;            
    	        i2s_config.dma_buf_len = MAX_SAMPLES;                   
    	        i2s_config.bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT;
    	        i2s_config.channel_format = I2S_CHANNEL_FMT_ONLY_LEFT;  
    	        i2s_config.use_apll = false,
    	        i2s_config.communication_format = I2S_COMM_FORMAT_I2S_MSB;
    	        i2s_config.intr_alloc_flags = ESP_INTR_FLAG_LEVEL1;
    	        i2s_config.dma_buf_count = 2;

		//install and start i2s driver

		ESP_ERROR_CHECK( adc_gpio_init(ADC_UNIT_1, ADC_CHANNEL_0) );
		ESP_ERROR_CHECK( i2s_driver_install(EXAMPLE_I2S_NUM, &i2s_config,  0, NULL) );
		ESP_ERROR_CHECK( i2s_set_adc_mode(I2S_ADC_UNIT, I2S_ADC_CHANNEL) );		


	void FillBufferI2S()
		uint16_t byteBuffer[MAX_SAMPLES];

		if (IsBufferFull())
			Serial.printf("BUG: FillBUfferI2S found buffer already full.");
		size_t bytesRead = 0;
    	        ESP_ERROR_CHECK( i2s_adc_enable(EXAMPLE_I2S_NUM) );
                ESP_ERROR_CHECK( i2s_read(EXAMPLE_I2S_NUM, (void*) byteBuffer, sizeof(byteBuffer), &bytesRead, portMAX_DELAY) );
	        ESP_ERROR_CHECK( i2s_adc_disable(EXAMPLE_I2S_NUM) );

		_cSamples = _MaxSamples;
		if (bytesRead != sizeof(byteBuffer))
			Serial.printf("Could only read %u byttes of %u in FillBufferI2S()\n", bytesRead, sizeof(byteBuffer));

		for (int i = 0; i < ARRAYSIZE(byteBuffer); i++)
			_vReal[i] = byteBuffer[i];

		//for (int i = 0; i < 128; i++)
		//	Serial.printf("%d, %f\n", i, _vReal[i]);

		_cSamples = MAX_SAMPLES;


Need to try this (from Reddit): ADC configured as an I2S peripheral that writes directly to system memory (DMA). https://www.reddit.com/r/esp32/comments/bid08m/finally_got_audio_sampling_via_dma_with_no_cpu/


nRF52840 SoC

High-end nRF52 Series multiprotocol SoC for high-performance, feature-rich applications with best-in-class security.

64 MHz Cortex-M4F
1 MB Flash, 256 KB RAM
2.4 GHz Transceiver
2 Mbps, 1 Mbps, Long Range
Bluetooth 5, Bluetooth mesh
ANT, 802.15.4, Thread, Zigbee
+8 dBm TX Power
128-bit AES CCM, ARM CryptoCell
12-bit ADC
USB 2.0