How to Create an Arduino Compatible Bluetooth 4.0 Module

I had been looking for a cheap alternative to some of the Arduino Bluetooth devices I’d seen, which in my opinion are overpriced.

Redbear’s Mini: $39.95 (Note: This is a uC and BLE combo).
Redbear’s Uno Shield: $29.95
BLEDuino: $19.95 (if part of Kickstarter)
Bluegiga Shield: $69.95

After seeing these, I thought I’d try to make one; this is my bumbling process for making an Arduino Bluetooth 4.0 device at home:

Updated efforts: http://letsmakerobots.com/node/39795
GitHub: https://github.com/Ladvien/HM-10

Step 1: How to Create an Arduino Compatible Bluetooth 4.0 Module

This guide is intended to show how to interface one of these HM-10 Bluetooth Low Energy modules to an Arduino.

I started working with these little Bluetooth modules in attempt to add Bluetooth 4.0 to my robot projects.

Step 2: Arduino BT 4.0 Module — Overview

There are a few bits of information I’d like to offer upfront.  First, I’m a homeless outreach worker; I’m not an engineer of any sort.  So, there will be mistakes in my design.

Second, although I was able to interface these BT 4.0 modules with an Arduino, I’ve not fully interfaced them with a PC or  mobile device.  This is due to the BT 4.0 software stacks being very different than earlier versions of Bluetooth (<3.0).

Still, I’ve shown that is possible to make this bridge using the Lightblue app for iOS.

It’s also one reason I write.  I’m too cheap to pay to develop an iOS app to interface with these modules and I don’t own an Android device with BT 4.0.  So, I’m hoping someone in the crowd will let me know when they’ve finished the software needed. 🙂

I will state that Jellybean 4.3 offers a Bluetooth 4.0 API.

Now, price is a big concern with me, so I’ll givet the breakdown up front:

The bill-of-materials (BOM):
1.HM-10 x 1
2.BS1138 x 1
3.0603 LEDs x 3 (best if assorted colors)
4.0805 Resistors 10k x 4
5.0805 Resistors 220 x  3
6.(OPTIONAL) SOT-23-5 LDO Voltage Regulator (it doesn’t make sense to use this, but I put the option on the board just in case. I’ll explain).

This should bring your total just under $10 USD.  And the boards I purchased from OSHPark, which come out to be less than $2 a piece.  Therefore, I figure around $12 for a BT 4.0 module.

I felt this price was better than some of the options available:

Redbear’s Mini: $39.95 (Note: This is a uC and BLE combo).
Redbear’s Uno Shield: $29.95
BLEDuino: $19.95 (if part of Kickstarter)
Bluegiga Shield: $69.95

Step 3: Arduino BT 4.0 Module — Order the Parts

Alright, if I’ve not scared you away then the first thing to do is select a layout.

I designed two different layouts, a Xbee footprint and a full breakout, which will fit nicely into a breadboard.

Xbee ($5.15) for 3 boards.

Breadboard breakout ($6.35) for 3 boards.

Order the components listed

The bill-of-materials (BOM):
1. HM-10 x 1
2. BS1138 x 1
3. 0603 LEDs x 3 (best if assorted colors)
4. 0805 Resistors 10k x 4
5. 0805 Resistors 220 x  3
6. (OPTIONAL) SOT-23-5 LDO Voltage Regulator (it doesn’t make sense to use this, but I put the option on the board just in case. I’ll explain).

The total time on the boards is ~16 days.

Step 4: Arduino BT 4.0 Module — Soldering

A few notes on soldering the SMD pieces:

DON’T BE SCARED.  It’s really not that hard.
1. There are three musts to SMD, at least from my perspective: a small iron tip,precision tweezers, thread-like solder (at least .022″ solder wire).

2. Other important soldering tools: A wet sponge and brass-ball will keep your fine soldering tip fine.  Sponge the solder tip, then run it through the brass-ball after each component to prevent build-up.

3. To speak blasphemy: Flux is ok, but I find the tweezers often take place of the flux.

4. Practice using both hands during soldering. Tweezers in one and solder-iron in the other.

5. The drag-to-solder method will be what you use on this board.

6. Patience.

7. Have a cup of wine.  Alcohol reduces performance on most skills, except, skills that involve fine motor control, there is a marked 20% improvement.  Though, this relationship is curve-linear.   One glass is good, two glasses and you’ll smoke something.

8. Honor the age old tradition: Don’t solder in your boxers.

Here is a video of me soldering the first iteration of the breakout board.

For more detail: How to Create an Arduino Compatible Bluetooth 4.0 Module