Author Topic: what have you bought lately that's cheap & cool?  (Read 21274 times)

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Offline ralphd

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what have you bought lately that's cheap & cool?
« on: September 22, 2015, 11:32:46 pm »
I'm into AVRs, and already have a collection of pro minis, a nano, full-size arduino clone, and a number of ATtinies - t13a, t85, t84a, & t88.  I also have a few different USBasps.  I've also got a couple HD44780 displays, some nrf24l01 modules, and 433Mhz ask/ook modules.
I also have a couple esp8266 modules, and have an esp-12e on order.
Any suggestions for something cool and cheap (under $5) to add to a nerd's collection?

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Offline sporadic

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Re: what have you bought lately that's cheap & cool?
« Reply #1 on: September 23, 2015, 01:40:03 am »
Cypress PSoC 4200 dev board at $4 is pretty good bang for the buck. If you're wanting to stay Atmel, the XmegaE5 series is interesting if you don't mind SMD parts. XCL on the E5 is fun and different.  The SAMD20's are nice for a Cortex M0+ part. You'll need to upgrade your programmer to something with PDI and SWD support though. The Atmel ICE at $50 is sweet and will give you debugging support for your AVRs. Aside from that, I'd spend the money on spinning your own dev boards for the nRF and ESP modules. NodeMCU is another great platform for the ESP-12 that you can use via Arduino with the ESP8266 project, around $10.
 

Offline ralphd

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Re: what have you bought lately that's cheap & cool?
« Reply #2 on: September 23, 2015, 02:05:53 am »
Cypress PSoC 4200 dev board at $4 is pretty good bang for the buck. If you're wanting to stay Atmel, the XmegaE5 series is interesting if you don't mind SMD parts. XCL on the E5 is fun and different.  The SAMD20's are nice for a Cortex M0+ part. You'll need to upgrade your programmer to something with PDI and SWD support though. The Atmel ICE at $50 is sweet and will give you debugging support for your AVRs. Aside from that, I'd spend the money on spinning your own dev boards for the nRF and ESP modules. NodeMCU is another great platform for the ESP-12 that you can use via Arduino with the ESP8266 project, around $10.

I have been giving a lot of thought lately to trying out some ARM parts.  I forgot to mention I don't like IDEs and prefer to do my development from a shell and vim.  So although the PSoC looks interesting, the Windows IDE is an issue.  Top of my list for possible ARM parts to try are the STM32F030s.  They have a UART bootloader in ROM, so I wouldn't need a SWD programmer to get started with them.  I don't see the need for a hardware debugger (like Atmel ICE or SWD), as I prefer to understand the hardware well enough to debug the code in my head.  I write a lot of code in AVR assembler, and when I write in C, I usually look at the disassembly (objdump -D) before flashing it.

I tinkered with eLua on the ESP8266, and wasn't impressed.  I like Igor is doing, and even submitted a patch to esptool-ck to support my zero-wire auto-reset circuit.
http://nerdralph.blogspot.ca/2015/04/zero-wire-auto-reset-for-esp8266arduino.html

So what do you think of the  F030K6T6?  70c ea seems like a great price (cheaper than an ATMega328p-au), and I already have a bunch of 0.8mm QFP-32 to DIP breakout boards in one of my parts drawers.
http://www.aliexpress.com/item/STM32F030K6T6-030K6T6-LQFP32-sell-SZNXDZ/32476188613.html
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Offline miguelvp

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Re: what have you bought lately that's cheap & cool?
« Reply #3 on: September 23, 2015, 02:16:59 am »
Still windows but the 5LP prototype board even at $10 instead of the 4200 $4 is a better deal:

http://www.cypress.com/documentation/development-kitsboards/cy8ckit-059-psoc-5lp-prototyping-kit

Comes with two 5LPs which cost about $10 each by themselves. The programmer part can program any PSoC so you don't need a miniprog nor a bootloader on the target PSoC.
 

Offline obiwanjacobi

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Re: what have you bought lately that's cheap & cool?
« Reply #4 on: September 23, 2015, 09:52:34 am »
Hehehe same here...

I came across this the other day, couldn't resist (isn't in yet)
http://www.ebay.com/itm/221728390701

I wanted to play with the TLC5940 led drivers so...
http://www.ebay.com/itm/291549056837?_trksid=p2057872.m2749.l2649
And to go with that some RGB LEDs (common anode!)
http://www.ebay.com/itm/20Pcs-LED-DIFFUSED-RGB-common-anode-4-PINS-F5-5MM-Super-Bright-Bulb-Lamp-/171907287706?hash=item2806790a9a

Also I didn't have one of these so...
http://www.ebay.com/itm/321557647999

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Online donotdespisethesnake

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Re: what have you bought lately that's cheap & cool?
« Reply #5 on: September 23, 2015, 10:43:55 am »
If you want some cheap STM32 modules then the Maple Mini clones are ideal, should be <$5. For some reason STM32 seems to be popular in China, there are many variants, mostly based on STM32F103.

You can ignore the Maple software, there are command line tools for Linux to download using the ROM UART bootloader.

I prefer to use a JTAG adapter for program/debug, there are cheap version of STLINK around, but the official ST one is not expensive. Can then use openocd, gdb according to preference. You also get a JTAG programmer built in to the Nucleo boards.
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Offline neslekkim

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Re: what have you bought lately that's cheap & cool?
« Reply #6 on: September 23, 2015, 11:25:59 am »
I wanted to play with the TLC5940 led drivers so...
http://www.ebay.com/itm/291549056837?_trksid=p2057872.m2749.l2649

I wonder if that seller sells good stuff, or fakes, it seems that he often have very cheap ic's.. hm...
 

Offline jdraughn

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Re: what have you bought lately that's cheap & cool?
« Reply #7 on: September 23, 2015, 12:19:31 pm »
http://www.banggood.com/7Pin-0_96-Inch-IICSPI-Serial-128x64-White-OLED-Display-Module-p-969266.html

I'm into AVRs, and already have a collection of pro minis, a nano, full-size arduino clone, and a number of ATtinies - t13a, t85, t84a, & t88.  I also have a few different USBasps.  I've also got a couple HD44780 displays, some nrf24l01 modules, and 433Mhz ask/ook modules.
I also have a couple esp8266 modules, and have an esp-12e on order.
Any suggestions for something cool and cheap (under $5) to add to a nerd's collection?
 

Offline vinicius.jlantunes

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Re: what have you bought lately that's cheap & cool?
« Reply #8 on: September 23, 2015, 12:46:12 pm »
Also I didn't have one of these so...
http://www.ebay.com/itm/321557647999

I wanted to play with the TLC5940 led drivers so...
http://www.ebay.com/itm/291549056837?_trksid=p2057872.m2749.l2649
I wonder if that seller sells good stuff, or fakes, it seems that he often have very cheap ic's.. hm...

Yeah, that protoboard PSU thingy is also very cheap at 0.99... makes you wonder indeed.

Offline neslekkim

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Re: what have you bought lately that's cheap & cool?
« Reply #9 on: September 23, 2015, 01:21:56 pm »
Also I didn't have one of these so...
http://www.ebay.com/itm/321557647999

I wanted to play with the TLC5940 led drivers so...
http://www.ebay.com/itm/291549056837?_trksid=p2057872.m2749.l2649
I wonder if that seller sells good stuff, or fakes, it seems that he often have very cheap ic's.. hm...

Yeah, that protoboard PSU thingy is also very cheap at 0.99... makes you wonder indeed.

The protoboard psu is from another seller, i think I bought one of those, and it works.

The GC supermarket sells lots of ic's of various kinds, very cheap most of it, but it's kinda more involved to find out if an chip is ok or not..
 

Offline obiwanjacobi

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Re: what have you bought lately that's cheap & cool?
« Reply #10 on: September 23, 2015, 01:28:09 pm »
http://www.banggood.com/7Pin-0_96-Inch-IICSPI-Serial-128x64-White-OLED-Display-Module-p-969266.html

Yeah I wanted to get one of those too, but they're all sold out..  :-\

I wanted to play with the TLC5940 led drivers so...
http://www.ebay.com/itm/291549056837?_trksid=p2057872.m2749.l2649

I wonder if that seller sells good stuff, or fakes, it seems that he often have very cheap ic's.. hm...

I know. Almost too good to be true, right? Well, we'll see. I have no experience with fake chips but if it works - that's all I need. And this is nothing serious, I mean I am not planning on making a product or anything, it's just tinkering... (nothing like the FTDI thing  :o)
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Offline ralphd

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Re: what have you bought lately that's cheap & cool?
« Reply #11 on: September 23, 2015, 02:57:53 pm »
Hehehe same here...

I came across this the other day, couldn't resist (isn't in yet)
http://www.ebay.com/itm/221728390701

I wanted to play with the TLC5940 led drivers so...
http://www.ebay.com/itm/291549056837?_trksid=p2057872.m2749.l2649
And to go with that some RGB LEDs (common anode!)
http://www.ebay.com/itm/20Pcs-LED-DIFFUSED-RGB-common-anode-4-PINS-F5-5MM-Super-Bright-Bulb-Lamp-/171907287706?hash=item2806790a9a

Also I didn't have one of these so...
http://www.ebay.com/itm/321557647999
I already have a couple of the breadboard power suplies.  Like most things, they're cheaper on Aliexpress than fleabay.
http://m.aliexpress.com/item/1751574564.html
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Offline obiwanjacobi

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Re: what have you bought lately that's cheap & cool?
« Reply #12 on: September 23, 2015, 05:10:49 pm »
Ah man! 21 cents down the drain!   :-DD
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Offline vinicius.jlantunes

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Re: what have you bought lately that's cheap & cool?
« Reply #13 on: September 23, 2015, 07:24:26 pm »
Jeez, that's unbelievable. What the heck, I will buy a few just for kicks, but it HAS to be dodgy, at that price!  :D

Offline ralphd

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Re: what have you bought lately that's cheap & cool?
« Reply #14 on: September 23, 2015, 11:24:15 pm »
Jeez, that's unbelievable. What the heck, I will buy a few just for kicks, but it HAS to be dodgy, at that price!  :D
The wonders of Shenzhen.  AMS1117 regulators are 3c ea, double-sided PCBs are 7-8c/sq in, mini USB connector and barrel jack are under 5c ea, and the caps are around 2c.  So the BOM is not much more than 25c.
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Offline bitseeker

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Re: what have you bought lately that's cheap & cool?
« Reply #15 on: September 24, 2015, 04:04:52 am »
Yeah, the prices sometimes do look too-good-to-be-true. However, after buying several things (microcontrollers, power modules, pots, knobs, etc.) from China via AliExpress or eBay, most have worked fine. So, it's hit or miss, but mostly good hits so far. One DC-DC buck converter I got via eBay had bulging SMD caps, but another module from the same seller was fine. It's funny, the replacement caps from Mouser cost more than I paid for the whole converter module, but we're still talking small change here, not big bucks.

The only real downside is that some shipments can take several weeks to arrive. Other times, they make it in about a week. :-//
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Offline obiwanjacobi

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Re: what have you bought lately that's cheap & cool?
« Reply #16 on: September 24, 2015, 04:07:19 am »
The most amazing feat I think is shipping a single (very small) package all the way from china to (in my case) the Netherlands - for free! WTF!?
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Offline bitseeker

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Re: what have you bought lately that's cheap & cool?
« Reply #17 on: September 24, 2015, 04:57:05 am »
Yeah, I know what you mean. My current hypothesis is that some people go on to buy higher-value or larger quantities of items, or they already have customers who purchase a lot (e.g., locals), and that makes up for the losses on the single unit sales.
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Offline motocoder

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Re: what have you bought lately that's cheap & cool?
« Reply #18 on: September 24, 2015, 06:18:26 am »
I think the Chinese government is subsidizing quite a bit - it's a calculated strategy to wipe out competition, and then dominate the market. Seems to be working.
 

Offline bitseeker

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Re: what have you bought lately that's cheap & cool?
« Reply #19 on: September 24, 2015, 06:33:28 am »
Ah, good point.

In order to minimize veering too far off-topic, I recently got one of these ESP-201 modules:

http://www.aliexpress.com/wholesale?SearchText=esp-201

It's like an ESP-12, but breadboard-friendly, or a NodeMCU module for those who already have a USB-to-TTL interface.
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Offline motocoder

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Re: what have you bought lately that's cheap & cool?
« Reply #20 on: September 24, 2015, 07:17:19 am »
Ah, good point.

In order to minimize veering too far off-topic, I recently got one of these ESP-201 modules:

http://www.aliexpress.com/wholesale?SearchText=esp-201

It's like an ESP-12, but breadboard-friendly, or a NodeMCU module for those who already have a USB-to-TTL interface.

I found an instructable on this device (ESP8266). This looks pretty useful. I was trying to remotely view some data coming out of a GPS chip, using one of the HC-06 modules, but it seems Microsoft broke the Bluetooth serial port implementation in Windows 10. I am looking for an alternative until they come up with a patch. I might be able to rig up something with this.
 

Offline dentaku

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Re: what have you bought lately that's cheap & cool?
« Reply #21 on: September 24, 2015, 12:23:05 pm »
EasyDriver http://www.ebay.com/itm/EasyDriver-Shield-stepping-Stepper-Motor-Driver-V44-A3967-For-Arduino-/400522271040
I can finally use all those bipolar stepper motors I salvaged from old stuff.

I'm also amazed that you can buy stuff from China inexpensively and the shipping is free. Of course it might take a month and a half to make it into Canada but that's what you have to deal with for that price. If you want something fast you order it directly from Amazon and it comes in a few days.
The cheapest stuff usually come in a padded envelope with the header pins not soldered so it will lay flat in the package.
 

Offline ralphd

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Re: what have you bought lately that's cheap & cool?
« Reply #22 on: September 24, 2015, 09:18:53 pm »
Ah, good point.

In order to minimize veering too far off-topic, I recently got one of these ESP-201 modules:

http://www.aliexpress.com/wholesale?SearchText=esp-201

It's like an ESP-12, but breadboard-friendly, or a NodeMCU module for those who already have a USB-to-TTL interface.

Those look like they take up most of the space on a breadboard.
My ESP-12E (it actually has ESP-12-Q silkscreened on it) arrived yesterday, and I plan to just solder short wires to a DIP-24 socket or a small pieced of protoboard with some header pins.
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Offline ralphd

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Re: what have you bought lately that's cheap & cool?
« Reply #23 on: September 24, 2015, 09:20:06 pm »
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Offline ralphd

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Re: what have you bought lately that's cheap & cool?
« Reply #24 on: September 24, 2015, 09:46:41 pm »
I think I've landed my best deal yet.  I found a seller listing 1000 DIP 74HC595 for just under $10.  I was a little suspicious, but I submitted the order anyway.  The vendor messaged me saying he made a mistake, and asked would I accept 100.  I countered saying his price was low for 1000, so I'd settle for 500.  He accepted, and said he would go out the next day to get them.
It seems he doesn't actually the parts, he just lists them on aliexpress, and when he gets orders he goes to Huaqiangbei (or someplace similar) to get the inventory.

At first it seems crazy that people can make a living doing this for what seems like so little money.  But then if you look at the data showing that around 2 billion people in the world live on less than $2/day.

Anyway, when the shift registers arrive, I'll have to find something to do with them.  One plan is to control a HD44780 display with an attiny13a.  I'll also start looking around for some cheap 8x8 LED matrix displays that I can control using 2 '595s for each.  I'm sure I'll end up giving away most of them though, maybe a tube for the local high school teacher doing a robotics class, another tube for the community college electronics prof....
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