EEVblog Electronics Community Forum

Electronics => Beginners => Topic started by: Jay112 on April 01, 2016, 10:59:51 pm

Title: Why are some small modules expensive?
Post by: Jay112 on April 01, 2016, 10:59:51 pm
I buy my XBee Pro 900HPs for about $40 from DigiKey. I've bought some Arduino units from eBay for about $3.50 each, and they've been working perfectly for months. Placing an Arduino Nano (for example) next to an XBee makes it seem surprising that 1 is $40 while the other is $3.50.

What are some of the factors that cause some modules to be way more expensive than others? Is it because they have a unique niche product that can't be replicated easily? Is it because they use a high-quality manufacturing process? Is it because they shouldn't really be that expensive, and the companies are making killer profit margins? Is it possible that the price is reasonable due to the higher-quality products, and the companies need the products to be that expensive in order to stay afloat?

I'm just interested in hearing some opinions about this. :)
Title: Re: Why are some small modules expensive?
Post by: Alex on April 01, 2016, 11:20:57 pm
It could be as simple as the manufacturing cost being higher. It is difficult to tell without making assumptions. In general products are priced up to whatever the customers are willing to pay. If you are on Mars and your spaceship needs a screw to get back to Earth, the Martian will charge you a fortune for it.

Alex
Title: Re: Why are some small modules expensive?
Post by: jeremy on April 01, 2016, 11:29:51 pm
In my experience, it is usually a mix of high r&d costs, vendor lock-in, certification costs and patents.

Occasionally with some unusual sensors it's due to low yield and/or low volume.
Title: Re: Why are some small modules expensive?
Post by: Psi on April 01, 2016, 11:31:57 pm
Because the XBee Pro 900HPs modules is intended for a market and usecase where $40 is normal.

Its like the difference between sparkfun and digikey.
The samw switch might cost $5 on sparkfun and 50c on digikey.

You will find RF modules from china that have similar specs to that xbee but cost much less. They wont be called xbee pro 900 though and not xbee protocol
Title: Re: Why are some small modules expensive?
Post by: ataradov on April 01, 2016, 11:50:22 pm
Anything RF requires extensive and expensive R&D and certification. China does not care about any of this, but good luck selling anything with cheap Chinese modules in the US. FCC will be all over your case.
Title: Re: Why are some small modules expensive?
Post by: vk6zgo on April 02, 2016, 12:10:18 am
Because the XBee Pro 900HPs modules is intended for a market and usecase where $40 is normal.

Its like the difference between sparkfun and digikey.
The samw switch might cost $5 on sparkfun and 50c on digikey.

You will find RF modules from china that have similar specs to that xbee but cost much less. They wont be called xbee pro 900 though and not xbee protocol

And if you have extraordinary luck,they will actually be tuned to the correct frequency! ;D
Title: Re: Why are some small modules expensive?
Post by: ade on April 02, 2016, 12:23:17 am
Quote
China does not care about any of this, but good luck selling anything with cheap Chinese modules in the US. FCC will be all over your case.

Plenty of Chinese modules are FCC certified.   Even some cheap ESP8266 modules are certified:

https://fccid.io/2ADUIESP-12-F
https://fccid.io/2AC7Z-ESPWROOM02

Title: Re: Why are some small modules expensive?
Post by: ataradov on April 02, 2016, 12:33:09 am
Plenty of Chinese modules are FCC certified.   Even some cheap ESP8266 modules are certified:
Some Wi-Fi modules are, but R&D on those modules is pretty minimal.

First of all, there is no equivalent of XBee from China. There is no way to build mesh network with cheap Chinese modules. And XBees are overkill for peer to peer communication.

Things like this take time and money to build and cost quite a bit - https://www.youtube.com/watch?v=QeSvAn-YRSE (https://www.youtube.com/watch?v=QeSvAn-YRSE)
Title: Re: Why are some small modules expensive?
Post by: ade on April 02, 2016, 12:50:33 am
Quote
there is no equivalent of XBee from China. There is no way to build mesh network with cheap Chinese modules.

There are plenty of inexpensive Zigbee 802.15.4 solutions from China.  Example:

https://fccid.io/2AGQG-NC880

Supports Zigbee, ZigbeePRO, ZigbeeRF4CE, 6LoWPAN.

Pricing: $5 qty.1.
Title: Re: Why are some small modules expensive?
Post by: Psi on April 02, 2016, 01:24:58 am
Also you could build a mesh network in software using a generic RF module that has programmable frequency.

It's not going to be anywhere near as fast as a hardware mesh network but it will work and maybe fine for your application.

In fact you could build a software mesh network with modules all on the same frequency. It would just need to use time division multiplexing for each node to perform its needed tasks. Transmit, receive, node identify and data relay.
256 time slots would be plenty for say 32 nodes
Sure, it's totally not scalable up to 10,000 but that may not be required.