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Published: Thursday, 07 March 2024 03:50

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Audio Bus interface

This section talks about communication i/f to xfer audio data. The audio genrating source are microphones, while speakers deliver that audio. In the past, microphones and speakers used to be analog sensing device, and their chip output was analog signal. However, analog signals being iprone to interference on PCB are never a preferred solution. So, now these microhones/speakers have a lot of analog logic on these chips itself, along with digital circuitry that can drive out these audio signals in digital binary format(string of 1's and 0's).

There are many different standards for transmitting digital audio data from one place to another. Some formats, such as I2S, TDM, and PDM are typically used for inter-IC communication on the same PC board. Others, such as S/PDIF and Ethernet AVB are primarily used for data connections from one PCB to another through cabling.

Audio BandWidth: Typical Audio data is sampled at 8KHz to 192KHz. It has 8bit to 32 bit resolution. For 8Khz and 8 bit resolution, we need 8k*8=64kHz bus frequency, or as high as 192k*32=6Mhz. As such, a lot of these interfaces don't need to run faster than few MHz.

Techincal doc by Analog Devices about I2C, TDM and PDM => https://www.analog.com/media/en/technical-documentation/technical-articles/MS-2275.pdf

I2S:

I2S is called Inter IC sound, and is the most common  digital audio format used for audio data transfer between ICs. The I2S standard was introduced by Philips Semiconductors (now NXP) in 1986 and was revised in 1996

Philips was bought NXP, and so bty he spec is mainatined y them here: https://www.nxp.com/docs/en/user-manual/UM11732.pdf

The attached diagram shows the waveform/connections.

FIXME ATTACH DIAGRAM --

I2S devices can either be in Master or slave mode. Master always drives Clock and Channel Select. Data can be driven either by Master or slave. There are 3 wires for I2S:

1. Clock => SCK (serial Clk) or BCLK (Bit clk). Master drives SCK.
2. Channel Select => WS (Word select) or LRCK (Left Right clk) or FS (Frame Sync). I2S can carry 1 or 2 channels of data. That channel is selected via this line, and it also serves to synchronize the frame (i.e it indicates start/end of current frame). 0= Left channel, 1=Right channel. It's better to think of WS as "Frame sync", as when you have > 2 channels, then WS will be a pulse, and in that case, it will indicate start of new frame. Master drives WS.
3. Data => SD (serial Data) or SDATA, SDIN, SDOUT. Either Master or slave may drive SD. However, SD is unidirectional - either master or slave drives it, but has to be configured beforehand as an i/p or o/p.

Apart from 3 wires, it may have variations where following lines are added. These signals are not part of spec, but added by certain companies for their product (and commonly supported).

1. Master clock => MCK (typically 256 x LRCLK) = commonly included for synchronizing the internal operation of the analog/digital converters. Master drives MCK along with WS.
2. Multiplexed data line for upload => Having dedicated SDAT lines for i/p and o/p. So, instead of 1 SD pin, we have 2 separate data pins with fixed direction => SDIN and SDOUT.

TDM:

When we talk about I2S, we are usually talking about legacy mode I2S as explained above. I2S can also operate in a Time Division Multiplexing (TDM) mode. We use this when we want to xfer more than 2 channels of data. That is not supported by legacy I2S. We can have multiple data i/p or o/p pin with 1 set of SCK and WS (might need multiple WS?). This will solve our problem of transmitting multiple channels. But that will increase the number of pins in system. Instead we want to use single data line for transferring audio signals from all channels. This is where TDM spec comes in. There is no standard for TDM interfaces, so ICs have their own slightly-different flavor of a TDM implementation. Since TDM has no spec, a common implementation includes all 5 signals used in I2C above: BCLK, LRCK, SDIN, SDOUT and optional MCK.

A TDM data stream can carry as many as sixteen channels of data and has a data/clock configuration similar to that of I2S. Each channel of data uses a slot on the data bus that is 1/Nth the width of the frame, where N is the number of channels being transferred. A TDM frame clock is often implemented as a single bit-wide pulse (rather than I2S’s alternating High and low for left and right channels). So, at start of WS pulse, we send fixed width of data for all N channels one after the other (called a frame), and then start of next WS pulse, we send next bits of data for all N channels and so on. Thus we avoid having multiple Data Lines. Clock rates are higher here at multi MHz (although < 25MHz) as multiple channels are supported on a single data line, so higher BW needed.

TDM is commonly used for a system with multiple sources feeding one input, or one source driving multiple devices. In the former case, each TDM source shares a common data bus. The source must be configured to drive the bus only during its appropriate channel, and tri-state its driver while the other devices are driving the other channels.

PDM:

PDM is another variation of I2S, where 2 channels are supported by using only 2 wires => Clk and Data. 2 PDM sources drive a common Data Out (DOUT) line which feeds into the PDM receiver's DIN line. A clock generated by the system master can be used by two slave devices, which use alternate edges of the clock to output their data on a common signal line.

PDM basics:PDM is Pulse Density Modulation. Here Audio data amplitude is represented via only 1 data line, by modulating the density of 1's and 0's to indicate higher or lower amplitude. When more 1's aretransmitted, then it's indicating a higher amplitude, and when more 0's are transmitted, it's indicating a low amplitude.

https://users.ece.utexas.edu/~bevans/courses/rtdsp/lectures/10_Data_Conversion/AP_Understanding_PDM_Digital_Audio.pdf

A PDM-based architecture differs from I2S and TDM in that the decimation filter is in the receiving IC, rather than the transmitting IC. The output of the source is the raw high sample rate modulated data, such as the output of a Sigma-Delta modulator, rather than a decimated data, as it is in I2S.

MEMS Microphone:

MEMS (Micro-Electro-Mechanical Systems) microphones come in a package (just like other chips). There may be analog or digital MEMS microphone. Analog ones produce an output voltage that is proportional to the instantaneous air pressure level. They have just 3 pins => VDD, Gnd and Output Voltage pin. This output pin is connected to a microcontroller on a PCB, which processes this analog o/p and produces bits. AIn a digital microphone, the whole circuitry to process the analog o/p and produce digital bitstream is put in a single package. So, it's lot better performance in terms of noise immunity.

Basic intro: https://www.edn.com/basic-principles-of-mems-microphones/

Digital Microphone Teardown: https://www.signalessence.com/blog/mems-microphone-teardown

There are 2 separate dies inside a digital mems microphone:

1. Microphone die: This die has the microphone accoustic sensor. This is made using same semiconductor production lines that is used for making transistors. Layers of different materials are deposited on top of a silicon wafer and the unwanted material is then etched away, creating a moveable membrane and a fixed backplate over a cavity in the base wafer.  The sensor backplate is a stiff perforated structure that allows air to move easily through it, while the membrane is a thin solid structure that flexes in response to the change in air pressure caused by sound waves. MEMS microphones need to have a hole in their package to allow sound to reach the acoustic sensor. 
2. ASIC die: This die is a digital/analog ckt that has a charge pump to place a fixed charge on the microphone membrane.  The ASIC then measures the voltage variations caused when the capacitance between the membrane and the fixed backplate changes due to the motion of the membrane in response to sound waves.  An ADC inside the ASIC converts the voltage variations into digital format for processing and/or transmission. Finally o/p is sent out in digital format using I2S, TDM, PDM. PDM data is captured by separate microcontroller/processor, which then decides what to do with it. Typically it converts PDM into PCM via dedicated hardware filters or in software and then it finally plays on speakers.

The microphone accoustic sensor itself is on silicon wafer, fabricated on semiconductor production lines using highly automated processes. Layers of different materials are deposited on top of a silicon wafer and the unwanted material is then etched away, creating a moveable membrane and a fixed backplate over a cavity in the base wafer.  The sensor backplate is a stiff perforated structure that allows air to move easily through it, while the membrane is a thin solid structure that flexes in response to the change in air pressure caused by sound waves.  

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Published: Friday, 23 February 2024 21:25

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Precious Metals - Gold, silver:

I'm not a big fan of buying gold/silver, etc for investment purpose. Nor buying it for showoff.

History:

Good article on historical gold and silver statistics is here .

Gold vs paper currency

Before Gold came into existence as currency, people used barter system to sell/buy things. This involved exchanging items with each other. Since this was very inefficient process, gold came into the process as a medium of currency. Gold mining has been taking place from about 5000 B.C. , so it has been about 7000 years, since gold has been used in some form as a currency or asset.

Gold has been used as a currency, since it's very easy to store, can't be produced artificially  and also limited in quantity. It's 20 times heavier than water, so 1 litre cube of gold = 10cmx10cmx10cm weighs 20kg, as compared to water of 1kg. So, at today's price of $2K/ounce, that 1 litre cube of gold would cost about $1M. Since it's limited in quantity and only exists in mines, no one can produce it artificially. Any thing that could be produced artificially by man, could not be used as currency. As such, gold was used as currency, and people had confidence that only so much gold was available.

Somewhere down the line, paper currency came into existence. Governments said that they will issue paper currency, which would be as good as gold. However, no one would believe in paper currency, as it was just a piece of paper. So, in order to make it work, it was backed by gold. That meant that the government would only issue paper currency in exchange for gold. So, let's say there was 1000 gram of gold in that country that was in circulation, then the govt would issue 1000 papers (assuming 1 paper was assigned value equal to 1 gram of gold). These 1000 papers would be held by the govt in treasury, and wouldn't be given to anyone. Now, whenever someone came with 1 gram of gold, govt would give him 1 piece of paper. That meant that the total amount of currency in circulation was still the same (999 gram of gold and 1 paper currency). Similarly, if more people came to exchange their gold with paper currency, govt would get more and more gold in exchange for these papers. After there is sufficient confidence in the system, most of the money in circulation would be paper currency, with an equivalent amount of gold sitting in the government treasury.  That gave confidence to paper currency, as it was conceptually equivalent to gold, but instead of carrying gold around, you could exchange this gold for paper currency from the issuer of paper currency, and then carry paper currency around, which was much easier. At any given point of time, if you wanted to get your gold back, you could take your paper currency to the govt and get an equivalent amount of gold.

There is no clear statistic on total amount of gold mined since the advent of civilization. According to the link at top, total amount of gold ever mined is 5.5B ounces or 165K metric tonnes (1 metric ton is 1000 kg). About 10% of the gold ever mined has been lost, used or unaccounted, so there's about 5B ounces or 150K ton of gold in circulation today. This article suggests that total amount of gold that is mined every year since 1995 is about 80M ounces or 2500 Metric tonnes.  World gold production peaked at 2.6K ton in the year 2001, and has been declining since then. In the year 2010, it was at 2.4K ton. Assuming $2K/ounce of gold price, that's $150B of gold that is mined every year. More than 50% of the gold ever mined has been mined in the last 50 years, and 90% of the gold ever mined has been mined since 1850. So, Gold supply is increasing by about 2% every year on an average. The aggregate un-mined known reserves of all the world's gold mining companies is approximately 45K tonnes as mentioned here . So, at current pace, somewhere around 2030, all of the known gold reserves will be exhausted, and then gold supply will increase very slowly.

Of this 150K ton of gold that has been mined, 50% is consumed in jewelery by mixing gold with other metals as copper, etc which results in 22k, 18k, 14k or 10k purity gold as pure 24k gold is too soft to be used in making any jewelery. 40% of gold is consumed as investment in gold coins, bars, govt reserves, etc and remaining 10% is consumed in industry for making solders, IC connections, medical uses, etc.

Indian households hold about 18K ton of gold, which is about 12% of all the gold in the world ever mined. Most of it is held in form of jewelery. Some estimates, put the amount of gold owned by Indian households to be 25K to 30K ton, which would be about 20% of all gold.

Governments hold gold in their reserves too, as bank's reserve assets. About 30K ton or 20% of gold is held by various governments. As of 2010 end, US Fed has the largest gold reserve at 8K ton (5%), Germany 3.5K ton, Italy and France 2.5K ton each, China and Switzerland at 1K ton each, Russia, Japan, Netherlands and India each at more than 0.6K ton of gold. IMF (International Monetary fund) holds about 3K ton, while ECB (European Central bank) holds about 0.5K ton of gold.

Gold is also held privately in stocks/funds . These funds actually buy physical gold on your behalf, when you buy such stocks. As of 2011, 2.5K ton or 2% of gold is held in such funds. The most widely traded such exchange traded fund is SPDR gold ETF (ticker GLD), traded in US stock market. It has about 1.2K ton of gold held in its stocks.

Aside from 40% of gold accounted above, 10% of the gold is in industrial materials. So, the remaining 50% of the gold ever mined is in various countries as household jewelery, gold coins, bars, etc (excluding indian households).

Gold producing countries:

The world’s top five gold producing countries mine about 50% of gold of the total mined output of 2.4K ton. Countries producing about 2/3rd of total gold production in world are as follows: China - 370 ton (15%), South Africa- 275 ton (11%), Australia - 250 ton (10%), USA - 250 ton (10%), Peru - 210 ton (9%), Russia - 160 ton (7%), Canada - 105 ton (5%). By comparison, India produces only about 2.5 ton or 0.1% of total gold produced every year. South Africa was the largest producer of gold for many decades, producing over 800 tons every year, but all easy pickings have been done, resulting in precipitous decline of new and existing gold mines. So, it's getting more difficult and expensive to mine new gold. While gold mining cost were around $200/ounce at start of 2000, they are now over $700/ounce and going higher each year. This ABN AMRO paper has good statistics on gold mining costs. Still at prices over $2K/ounce, it's still profitable business.

Gold consuming countries:

In 2011, there was demand for about 4K ton of gold. Gold is not consumed in the true sense. 2K ton (50%) was consumed in jewelery, 1.6K ton (40%) in investment (1.4K ton in bars/coin, while 0.2K ton inETFs), and remaining 0.4K ton (10%) in industrial applications. Note that before the bull run of gold (year 2003 and before), about 80% of gold demand was for jewelery, 10% for investment and 10% for industrial applications. So, the rising price of gold has generated a lot of demand for gold as an investment. Since annual production of gold is about 2.4K, while demand is 4K, the shortfall is made up by recycling scrap gold, as well as by sale of gold by Banks around the world. The world’s largest consumer of gold is India, at 800 ton (20%), then China at 500 ton (12%), and a distant third is USA at 125 ton (3%). Rest all countries consume less than 100 ton, and consume roughly in line with what they produce. Gold demand has fallen significantly for all countries except India and China, since 2003 as prices for gold went up by a factor of 5. India's gold import was 1K ton in 2011, a record high.

Buying/Selling Precious Metals = Gold, Silver, Platinum, Palladium:

Gold/Silver coins are the best way to buy these precious metal, as they may be gifted to others. Platinum and Palladium and two other metals, that are considered alternative to gold, and are highly traded. However, we'll be looking at gold/silver only. There are few terms that we need to know before rushing to buy these.

• Weight (in troy oz): The most common weight for these coins is 1troy oz (31.1g). NOTE: it's NOT 1 oz, as 1 oz is only 28.3g. We quote Gold/Silver in troy oz in USA and in international markets. Coins may be more than 1 troy oz in weight, as they have to be mixed with other metals to make them more durable. Many reputed mint companies will guarantee that gold/silver content itself is 1 troy oz. Most commonly seen with gold coins, where the weight of gold coin is 5-10% more than 1 troy oz, to give you 1 troy oz of gold.
• Spot Price: Spot price is the price at which gold/silver is sold in huge commodity markets. Usually you have to pay a premium over the spot price to buy these from online merchants, as they have shipping costs, credit card costs, insurance cost, etc. No one can sell you physical gold/silver etc for spot price, as they will lose money doing that.
  • 2023: As of 2023, spot price for 1 troy oz of metals is: Gold = $2K,silver = $20, Platinum and Palladium = $1k. Coins for 1 oz sell for 2%-5%
• Purity: Gold/Silver also have a purity noted on them, which specifies how much of the weight is pure gold/silver. Generally, these coins are mixed with other metals to make them more mintable. It's common to see gold/silver coins mixed with other metals. In India most coins are sold at 92% purity (i.e only 92% of the weight of the coin/bar is precious metal, the other 10% is less precious metal as Silver,Copper, etc). But they are priced as if it's 100% gold/silver. Gold/Silver purity is noted in karats. karats indicate the proportion of precious metal out of a total of 24 karats. 24 karats is 100% pure gold, So, a 22 Karat gold is 22/24=91.67% gold content. Most places sell gold at 18 karat or 22 karat purity. Here in US, all sorts of coins are sold with different purity levels. Purity is also noted in "spine". Four nines (99.99% or 0.9999) is called four spine. Three nines (99.9% or 0.999) is called three spine. A lot of coins that are minted by individual companies are 3 spine, that's 99.90%. Typically four spine is a little more valuable because there is more gold. Chinese gold pandas are 3 spine, for example. Us liberties or Buffalos are 4 spine.
  
• Minting Companies: Companies may mint their own coins, and sell them. These don't have that lure, as you these are NOT considered currency. US Mint ( branch of Treasury Dept of US govt) has the authority to mint coins and sell gold, silver, Platinum and Palladium coins in different sizes. It doesn't directly sell to general public, via sells them via it's authorized sellers. These US Mint Coins are highly sought after, as they are internationally recognized as being of highest purity, backed by US govt and have legal tender value just like US currency (i.e 1 Dollar Gold coin has $50 written on it, meaning US govt will pay you $50 if you decide to use it as a legal tender. No one does it, since market price of that coins is lot higher at $2000) and may be included in Retirement (i.e. IRA) accounts too.
  • Link to US Mint coins: https://en.wikipedia.org/wiki/Coins_of_the_United_States_dollar => For Gold/Silver coins, the gold reference is "American Eagle" coins. They have guaranteed 1 oz of gold/silver with 3 or 4 spine purity. However, they carry premium over spot price.
    
    • American Gold Eagle (AGE): These are the only gold coins that you should buy as they may usually be bought with only 2% premium over spot price of gold. One thing to note is that these coins have low purity of 91.67% (22/24*100) as it's 22 carat gold. It has 3% Silver and 5.67% copper. However, it still contains 1 troy oz of gold, as the total weight of coin is 1.091 Troy oz, with 1 troy oz of that being gold. It's very durable, but less shiny than other coins which are 99.9% pure gold.
    • American Buffalo (AB): These were first minted in 2006, and are the only 24 karat gold coins with 99.99% purity offered by US Mint. These were offered to compete with pure gold coins offered by Canadian and Australian Mintage. Since these have no other metal content, their weight is 1 troy oz. They are more delicate and easy to chip, or get their gold brushed off.So, they have to be kept in a box or package.
    • American Silver Eagle (ASE): ASE are composed of 99.9% silver and 0.1% copper. These coins usually sell for $3-$4 over spot price of silver. You may buy other Silver coins (NOT ASE) by other minters which may be only $1-$2 premium over spot price. But expect to pay at least 5% over spot price, which makes it lot more difficult to make as much profit when selling (compared to gold).
  • Other Govt Mint coins: Government of many countries around the world also mint gold/silver coins. Some of the popular ones are Canadian Gold Maple Leaf (GML) coins with 99.99% purity, South African Krugerrand Gold coins of 22 Karat (Same as AGE with total weight being 1.09 oz), Australian Kangaroo coins produced by Australian Mint and Britannia coins produced by British Royal Mint. They are all guaranteed by the respective Governments, so are equally safe.
  • I would personally prefer to only buy AGE, and not bother with any other gold coins. They are very liquid, and easy to buy/sell. For Silver coins, since the premium for ASE is 20% over the spot price, I would prefer to buy it local minting companies, which sell it to you for 5%-10% over the spot price. You easily lose 2%-3% in gold and 5%-10% in silver each time you buy/sell compared to spot price. As for my recommendation, you should never ever sell anything you buy. So, just buy and keep it forever !!

Below are few merchants where you may buy these. 

EBAY: I used to buy them on ebay before 2014, as at that time they allowed you to buy gold/silver using ebay GC, which you could regularly get on discount for 5%-20%. So, that was a pretty good deal (easy 5%-20% profit). Since 2014, they stopped accepting GC for buying any precious metals. Now, there's no reason to buy on ebay. Actually you should avoid buying on ebay, as ebay has gone downhill, and still going that path. Lots of other retailers offer much better service at the same price.

COSTCO/WALMART: As of 2023, 2 biggest retailers - Walmart and Costco have started offering Gold/silver coins. Costco usually have gold coins on sale from time to time with only $30-$40 over the spot price of Gold. Silver coins go less on sale. However, their American Eagle silver coins usually sell for only $2 over spot price per coin, which is a decent markup (Not a bad deal, as other retialers usually have > $2 markup on these coins). Walmart has gold/silver coins via 3rd part sellers. One of the most reputed 3rd party sellers is "APMEX", but you may buy from any 3rd party sellers, as Walmart stands behind the product. Whenever I've Walmart GC to burn, I usually end up buying these gold/silver coins.

Shipping is always free, item is non returnable, and you can pay with credit card, and earn points (1%-2%). 

DEALS:

Costco:

• 02/23/2024: Tube of 20, 1 oz American Eagle silver coins ($4/oz over spot price) => https://slickdeals.net/f/17313610-costco-members-2024-1-oz-american-eagle-silver-coin-20-count-539-99
• 02/22/2024: 1 oz Canada Maple Gold coin for $2080 ($45/oz over spot price) => https://slickdeals.net/f/17312812-2024-1-oz-canada-maple-leaf-gold-coin-costco-2079-99

Walmart:

• Everyday: APMEX via ebay for 5 generic silver coins (usually $2 over spot price) => https://www.walmart.com/ip/1-oz-Silver-Round-Buffalo-Lot-of-5-Walmart/1265739638

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Published: Thursday, 01 February 2024 14:57

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Diet and Supplements

There are lots of things that we need in our diet to fulfill our body's nutritional requirement. First there are are amino acids, then Vitamins, minerals, etc. Let's look at some of these.

Proteins:

A more detailed section on Proteins is in "Biology" section. Brief summary is again presented here.

Proteins are needed for body to build muscles. Proteins is in larger amount in meat products, but not so much in plant based products. So, for vegetarians, the big source of Proteins comes from dairy based products as milk, yogurt, cheese. For vegans, even dairy products are off the menu, so they have even limited things to fulfill their protein requirement.  It's also in lentils, beans, tofu etc for vegetarian and vegans out there. Our body needs massive amounts of protein to help build and maintain muscles. At a minimum, our body needs 0.36 g of protein per lb of weight or 0.8 g of protein per kg of body weight. Most people around 60 kg of weight need 45g-50g of protein per day. Basically every year you need to consume about 18Kg of Protein, which is 25% of your body weight. This is huge amount of protein, and that's needed just to maintain what you have !!

Link below states 0.8g to 1.2g of protein per kg of body weight. Very active people as body builders, marathon runners may go up to max of 2g of protein per kg of body weight but that's the upper limit. Too much protein may put stress on your kidneys as the by product from protein breakdown is Nitrogen which needs to be excreted out via kidneys.

Link => https://getpocket.com/explore/item/the-truth-about-protein-how-to-get-enough-at-every-age

I'm listing below Protein products for a vegetarian diet:

Plants don't have too much protein. Each cup size serving may have max of 2g protein, which isn't going to suffice for your body, no matter how much plant you eat. Here are top vegetables rich in protein => https://www.self.com/story/high-protein-vegetables

Beans are another option for vegetarians, but lot of beans do cause gas and bloating (you might have heard that before from your elders).

Protein based supplements: You will have to supplement with Protein supplements. One of the most popular ones is whey protein. ON whey protein may be had for $10/lb (or $20/kg), which is a good price. It will cost you < $1/day in protein supplement.

 Isolate usually has higher protein concentration, but online videos claim there's not much difference b/w isolate and concentrate. FIXME ...

Meals:

• Breakfast: Get 2 bread slices (each 5g of protein for whole wheat bread with multi grain) with peanut butter on it (5 g of protein for 1 tablespoon). Drink a glass of milk (another 8g of protein in one glass) with Protein powder (1 scoop is around 10g of protein) in it. Do take 10 nuts which give you about 5g of protein. This will will give you around 30g-35g of protein in the morning meal.
• Lunch/Dinner: For a vegetarian diet, I don't count too much on protein intake in home made curries, roti

Calcium:

Calcium is needed for bone development, and 1.2g per day is the recommended amount. Basically you need to consume 1/2 KG of calcium every year, which is a lot of calcium.

Vitamins:

Vitamin B12: Very essential

Deals: 

2025:

01/03/2025: Amazon Dymatize whey protein for $42 (5 lb)

This is cheaper than Costco, but brand is different. Also, it's concentrate and NOT isolate, which usually has slightly lower protein content. People like their Isolate version. This is cheaper than even Costco ON Whey protein, but this price is only for 1st S&S order.

https://slickdeals.net/f/18036396-5-lbs-dymatize-elite-100-whey-protein-powder-chocolate-42-13-w-s-s-free-shipping

2024:

12/26/2024: Costco ON whey protein for $49 (5.5 lb) in store => expires 01/20/2025

Costco has 5.5 lb (2.5Kg) ON whey protein isolate for $55 online and $49 in store.  Prices are lowest for buying in store. It's 5.47 lb for Vanilla flavor, and 5.64 lb for Chocolate flavor, but both of them have same protein 24g per scoop. Vanilla has 2g protein per 31g, while Chocolate has 24g protein per 32g. Either way, price is < $20/kg which is as low as it can get. So load up.

https://slickdeals.net/f/18002616-costco-members-5-64-lbs-optimum-nutrition-gold-100-whey-protein-powder-55-free-shipping

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Published: Monday, 22 January 2024 06:03

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Deals: 

 Here are the deals from 2024. For deals from 2023, go to DEALS 2023

Deals starting from November till New year (aka Black Friday deals) for 2024 are also under this section itself

I've sticky deals and regular deals. Regular deals are posted below which are offered just one time. Sticky deals have separate section of their own, as they refer to deals which are offered multiple times a year.

Bank and Brokerage Deals (updated 2025):

01/01/2025: All bank and Brokerage bonus deals from 2025 onwards have been moved to "Sticky Deals" section

Previous unexpired/extended bank/brokerage deals from 2024 and before: 

10/28/2023: Robinhood (RH) Brokerage Offer of 1% bonus on total assets transferred  (3% bonus on IRA transfers) - expires Dec 8, 2023 expires Apr 30, 2024 (1% bonus offer extended to June 28, 2024)

Look in brokerage account bonus section for details of the offer: best brokerage bonus

10/20/2023: Chime - $245 $250 in SwagBucks for $200+ in direct deposit within 30 days (nationwide) => expires Oct 31, 2023 extended to Nov 30, 2023 Feb 29, 2024 Mar 31, 2024

Look in bank account bonus section for details of the offer: best bank bonus

UPDATE 03/18/2024: $10 bonus for tipping someone $10 or more. Valid 03/18/2024 - 03/20/2024. See above link for details

10/20/2023: TastyTrade (previously known as TastyWorks) Brokerage Bonus Offer of $2K for $100K+ - expires Mar 31, 2024. Ongoing as of July, 2024

Look in brokerage account bonus section for details of the offer: best brokerage bonus

10/01/2023: Wells Fargo - $325 for $1K+ in direct deposit within 90 days (nationwide) => expires Nov 13, 2023. extended to Jan 16, 2024 Apr 9, 2024

Look in bank account bonus section for details of the offer: best bank bonus

11/05/2023: Capital One - $1500 bonus for $100K+ in deposit in Savings account (nationwide) => expires Dec 6, 2023 => Still active as of 04/04/2024

Look in bank account bonus section for details of the offer: best bank bonus

Current Deals:

2024: 

12/26/2024: Costco ON whey protein for $49 (5.5 lb) in store => expires 01/20/2025

Look in "diets and supplements" under health section for details of the offer: diet and supplements

11/21/2024: Tracfone offer via HSN - 1 year service plan + 2 phones for $110 or less

Look in "phone services" under services section for details of the offer: phone service

10/26/2024: Open a Checking a/c at Alliant CU with $500+ DD - - get $150 via rakuten => expires Nov 2, 2024 (Now $200 as of 12/27/2024)

Look in bank account bonus section for details of the offer: best bank bonus

10/10/2024: Robinhood (RH) Brokerage Offer of 1% (or 2%) bonus on total assets transferred  (3% bonus on IRA transfers) - Valid from 10/16/24 to 10/27/24

Look in brokerage account bonus section for details of the offer: best brokerage bonus

09/28/2024: TradeUp Brokerage Bonus Offer => $2K bonus for $100K+ in brokerage account transfer => expires 31st Dec, 2024

Look in brokerage account bonus section for details of the offer: best brokerage bonus

10/01/2024: Bank of America - $300 bonus for $2K+ in direct deposit within first 3 months (nationwide) => expires Jan 31, 2025

Look in bank account bonus section for details of the offer: best bank bonus

09/25/2024: Laurel Road - $300 bonus + $20/month for $2.5K+ in direct deposit (nationwide, open to non-nurses too) => expiry unknown

Look in bank account bonus section for details of the offer: best bank bonus

09/15/2024: P&G - $15 rebate on $50+ for P&G selected items bought from any store: valid 09/15/24 to 12/29/24

Look in "stores" under shopping section for details of the offer: stores

09/10/2024: BMO Harris - $500 + $100GC for $7.5K+ in direct deposit within first 3 months (nationwide) => expires Oct 31, 2024

Look in bank account bonus section for details of the offer: best bank bonus

09/02/2024: Quorum Federal Credit Union - $300 for $1K+ in direct deposit in 60 days (nationwide) => expiry unknown

Look in bank account bonus section for details of the offer: best bank bonus

09/01/2024: US Bank - $450 for $8K+ in direct deposit in 3 months (only in selected states) => expires Sept 26, 2024

Look in bank account bonus section for details of the offer: best bank bonus

08/31/2024: Farmers Insurance Federal Credit Union (FIGFCU) - $250 for $5K+ in direct deposit per month for 3 months (nationwide) => expiry unknown

Look in bank account bonus section for details of the offer: best bank bonus

08/28/2024: Open a CD at Alliant CU - get $200 via rakuten => expiry unknown

Look in bank account bonus section for details of the offer: best bank bonus

08/20/2024: Chipotle Offer - BOGO by answering quiz questions => valid from 08/20/2024 - 08/22/2024

Look in "fast food" under food section for details of the offer: fast food

08/19/2024: Sofi Hybrid checking and savings account - ($200 via swagbucks, $250 $350 via Rakuten) + $300 for direct deposit  => expiry unknown

Look in bank account bonus section for details of the offer: best bank bonus

08/19/2024: Apple Ipad (9th gen, 2021 model) for $200 (various retailers), 10th gen (2022 model) for $250 on BF => (expiry => until they sell out everywhere)

Look in "electronics" under shopping section for details of the offer: electronics

08/16/2024: Six Flags - Yearly pass valid for 2024 and 2025 for $60-$100 => expires Labor Day

Look in "kids stuff/activities" under shopping section for details of the offer: kids stuff/activities

08/16/2024: Target - Free Ulta beauty product -  valid from 08/04/2024 to 08/31/24

Look in "Personal care & Apparel" under shopping section for details of the offer: Personal Care & Apparel

08/15/2024:  Free Google Pixel 9 with Apple/Samsung Tradein at BestBuy - expiry unknown

Look in "phone services" under services section for details of the offer: phone service

08/10/2024: Cici's Pizza - Buffet for $5 only (valid on Mondays and Tuesdays only) => expires Nov 12, 2024

Look in "fast food" under food section for details of the offer: fast food

08/01/2024: Sofi Brokerage Bonus Offer => 1% bonus for conversion and transfer from 401K rollover account to IRA account => expires 15th Sept, 2024

Look in brokerage account bonus section for details of the offer: best brokerage bonus

07/18/2024: WeBull Brokerage Bonus Offer => up to 3.5% match for IRA transfer and 2% for regular Brokerage account transfer (ymmv extra 3% APY on cash)=> various expiry dates

Look in brokerage account bonus section for details of the offer: best brokerage bonus

07/03/2024: Charles Schwab Brokerage Bonus Offer of upto $6K for new/existing accounts => expiry unknown

Look in brokerage account bonus section for details of the offer: best brokerage bonus

07/01/2024: 7-Eleven Stores - Free small slurpee only on 07/11 (Thursday) => expires July 11, 2024

Look in "fast food" under food section for details of the offer: fast food

06/20/2024: Axos Bank Rewards checking account - ($125 via rakuten) + $500 for direct deposit  => expires July 31, 2024

Look in bank account bonus section for details of the offer: best bank bonus

05/31/2024: Etrade Brokerage Bonus Offer => $5K bonus for regular brokerage account transfer => expires 31st July, 2024

Look in brokerage account bonus section for details of the offer: best brokerage bonus

05/25/2024: WeBull Brokerage Bonus Offer => 1.25% bonus for regular brokerage account transfer => expires 30th June, 2024

Look in brokerage account bonus section for details of the offer: best brokerage bonus

05/06/2024: BMO Relationship Checking account - $500 for $7.5K in direct deposit  => expires Sep 9, 2024

Look in bank account bonus section for details of the offer: best bank bonus

04/28/2024: Taco Bell - Discovery box for $5, valid only on Tuesdays => expires June 4, 2024

Look in "fast food" under food section for details of the offer: fast food

04/22/2024: Dominos Offer - Large 2 topping Pizza for $7 => expires 04/28/2024

Look in "fast food" under food section for details of the offer: fast food

04/11/2024: Walmart - Water Bead Blaster for $12

Look in "kids stuff/activities" under shopping section for details of the offer: kids stuff/activities

04/07/2024: Target Git Card Offer - 10% off  (valid only on  04/13)

Look in gift card section for details of the offer: gift cards

03/21/2024: Tracfone/Motorola offer via QVC/HSN - 1 year service plan + free phone for $40- $70

Look in "phone services" under services section for details of the offer: phone service

03/10/2024: Axos Bank checking and savings account - ($175 via swagbucks) + $300 for direct deposit  => expires July 31, 2024

Look in bank account bonus section for details of the offer: best bank bonus

03/09/2024: Southwest $500 GC for $430 on costco.com : expires 03/10/2024 

Look in "flights" under food section for details of the offer: flights

03/01/2024: Free "One Plus Nord N30" phone  at BestBuy with AT&T service

Look in "phone services" under services section for details of the offer: phone service
 

03/01/2024: Sofi Hybrid checking and savings account - ($200 via swagbucks, $250 via rakuten) + $300 for direct deposit  => expiry unknown

Look in bank account bonus section for details of the offer: best bank bonus

02/29/2024: Multiple phones as "One Plus Nord N30, Motorola g Stylus, etc" for $40 or more with Metro (by T-mobile) service

Look in "phone services" under services section for details of the offer: phone service

02/28/2024: Truist - $400 for $500+ in direct deposit (only in selected states) => expires June 26, 2024 expires Apr 30, 2025

Look in bank account bonus section for details of the offer: best bank bonus

02/27/2024: WeBull Brokerage Bonus Offer => up to 4.5% match for IRA transfer => expires 30th Apr, 2024

Look in brokerage account bonus section for details of the offer: best brokerage bonus

02/01/2024: Pennzoil Oil Rebate: $25 rebate for 10 quart synthetic oil => Runs from Feb 1, 2024 - September 30, 2024

Look in "gasoline/oil deals" under Auto section for details of the offer: gasoline/oil deals

01/29/2024: Elements Financial Credit Union => $400 bonus for Checking account (nationwide) => expires Mar 25, 2024 => Expired Early in Jan, 2024

Look in bank account bonus section for details of the offer: best bank bonus

01/25/2024: Tracfone offer - 1 year service plan + free phone for $60

Look in "phone services" under services section for details of the offer: phone service

01/20/2024: Printable coupon for Free Dannon Yogurt => expires on 01/31/2024

Look in "food/grocery" section for details of the offer: food/grocery