diff --git a/ble.go b/ble.go
new file mode 100644
index 0000000..121e1ab
--- /dev/null
+++ b/ble.go
@@ -0,0 +1,246 @@
+package ble
+
+import (
+	"fmt"
+	"sync"
+	"time"
+
+	"git.wow.st/gmp/ble/gatt"
+)
+
+type PeripheralListItem struct {
+	p    Peripheral
+	seen time.Time
+}
+
+type Peripherals struct {
+	items []PeripheralListItem
+	sync.Mutex
+}
+
+type ConnectionListItem struct {
+	p     Peripheral
+	state chan string
+}
+
+type Connections struct {
+	items []ConnectionListItem
+	close chan struct{}
+	sync.Mutex
+}
+
+func (c *Connections) UpdateState(p Peripheral, s string) {
+	var ch chan string
+	c.Lock()
+	for _, item := range c.items {
+		if p.Identifier == item.p.Identifier {
+			ch = item.state
+		}
+	}
+	c.Unlock()
+	ch <- s
+}
+
+func (ps *Peripherals) Add(x Peripheral) bool {
+	ps.Lock()
+	defer ps.Unlock()
+	found := false
+	for n, item := range ps.items {
+		if item.p.Identifier == x.Identifier {
+			item.p = x
+			item.seen = time.Now()
+			ps.items[n] = item
+			found = true
+			break
+		}
+	}
+	if found {
+		return false
+	}
+	//take ownership of this object
+	x.Retain()
+	item := PeripheralListItem{p: x, seen: time.Now()}
+	ps.items = append(ps.items, item)
+	return true
+}
+
+func (cs *Connections) Add(x ConnectionListItem) bool {
+	cs.Lock()
+	defer cs.Unlock()
+	found := false
+	for _, item := range cs.items {
+		if item.p.Identifier == x.p.Identifier {
+			// are we allowed to have multiple connections to the same peripheral?
+			return false
+		}
+	}
+	if found {
+		return false
+	}
+	cs.items = append(cs.items, x)
+	return true
+}
+
+type UpdateStateEvent struct {
+	State string
+}
+
+type DiscoverPeripheralEvent struct {
+	Peripheral Peripheral
+}
+
+//FIXME: create a Service type that is platform dependent to make the
+//event platform independent
+type DiscoverServiceEvent struct {
+	Peripheral Peripheral
+	Gatt gatt.Service
+	Service Service
+}
+
+//FIXME: create a Characteristic type that is platform dependent to make the
+//event platform independent
+type DiscoverCharacteristicEvent struct {
+	Peripheral Peripheral
+	Gatt gatt.Characteristic
+	Service Service
+	Characteristic Characteristic
+}
+
+//FIXME: create a Characteristic type that is platform dependent to make the
+//event platform independent
+type UpdateValueEvent struct {
+	Peripheral Peripheral
+	Characteristic Characteristic
+	Data []byte
+}
+
+type ConnectEvent struct {
+	Peripheral Peripheral
+}
+type ConnectTimeoutEvent struct {
+	Peripheral Peripheral
+}
+
+type UpdageValueEvent struct {
+	Peripheral Peripheral
+	Characteristic gatt.Characteristic
+}
+
+func (b *BLE) Events() chan interface{} {
+	return b.events
+}
+
+func (b *BLE) State() string {
+	b.Lock()
+	defer b.Unlock()
+	return b.stringState()
+}
+
+func (b *BLE) Scan() {
+	b.Lock()
+	defer b.Unlock()
+	if b.readyToScan() {
+		b.peripherals.Lock()
+		b.peripherals.items = b.peripherals.items[:0]
+		b.peripherals.Unlock()
+		fmt.Printf("Go: Scanning\n")
+		b.scan()
+	} else {
+		b.wantScan = true
+	}
+}
+
+func (b *BLE) StopScan() {
+	b.Lock()
+	if !b.ready {
+		b.Unlock()
+		return
+	}
+	b.Unlock()
+	fmt.Printf("Go: stopping scan\n")
+	b.stopScan()
+}
+
+func connectTracker(b *BLE, x ConnectionListItem) bool {
+	fmt.Printf("connectTracker(): %s\n", x.p.Name)
+	b.connections.Lock()
+	for _, item := range b.connections.items {
+		if item.p.Identifier == x.p.Identifier {
+			fmt.Printf("connectTracker(): already connecting to %s\n", x.p.Name)
+			b.connections.Unlock()
+			return true
+		}
+	}
+	b.connections.items = append(b.connections.items, x)
+	b.connections.Unlock()
+	b.connectPeripheral(x.p)
+
+	cancel := func() {
+		b.cancelConnection(x.p)
+		b.connections.Lock()
+		for n, item := range b.connections.items {
+			if item.p.Identifier == x.p.Identifier {
+				b.connections.items = append(b.connections.items[:n], b.connections.items[n+1:]...)
+			}
+		}
+		b.connections.Unlock()
+	}
+
+	go func() {
+		tick := time.NewTicker(time.Second * 5)
+		select {
+		case <-b.connections.close:
+			fmt.Printf("connectTracker(): Closing connection to %s\n", x.p.Name)
+			b.cancelConnection(x.p)
+		case <-tick.C:
+			fmt.Printf("connectTracker(): Connection to %s timed out\n", x.p.Name)
+			cancel()
+			b.events <- ConnectTimeoutEvent{x.p}
+		case state := <-x.state:
+			if state == "cancel" {
+				cancel()
+			}
+			fmt.Printf("connectTracker(): state %s\n", state)
+		}
+	}()
+	return true
+}
+
+func (b *BLE) Connect(p Peripheral) bool {
+	b.Lock()
+	if !b.ready {
+		b.Unlock()
+		fmt.Printf("--BLE not ready\n")
+		return false
+	}
+	b.Unlock()
+	if p.p == nil {
+		var ok bool
+		p, ok = b.knownPeripheral(p)
+		if !ok {
+			return false
+		}
+	}
+	item := ConnectionListItem{p, make(chan string)}
+	fmt.Printf("BLE.Connect() calling connectTracker\n")
+	return connectTracker(b, item)
+}
+
+func Disconnect(p Peripheral) {
+	b := peripheralLookup(p)
+	found := false
+	b.connections.Lock()
+	for i, item := range b.connections.items {
+		if item.p.Identifier == p.Identifier {
+			found = true
+			b.connections.items = append(b.connections.items[:i], b.connections.items[i+1:]...)
+			break
+		}
+	}
+	b.connections.Unlock()
+	if !found {
+		return
+	}
+	b.cancelConnection(p)
+}
+
diff --git a/ble_darwin.go b/ble_darwin.go
index ed3b210..c9aea34 100644
--- a/ble_darwin.go
+++ b/ble_darwin.go
@@ -31,6 +31,9 @@ var cdLookup map[unsafe.Pointer]*BLE
 var pdLookup map[unsafe.Pointer]*BLE
 var pcache map[unsafe.Pointer]*Peripheral
 
+func peripheralLookup(p Peripheral) *BLE {
+	return pdLookup[p.p.Ptr()]
+}
 
 type State string
 
@@ -42,6 +45,24 @@ type Peripheral struct {
 	p *ns.CBPeripheral
 }
 
+type Service *ns.CBService
+type Characteristic *ns.CBCharacteristic
+
+//Init needs to be called before the BLE library can be used. No setup needed
+//on Darwin.
+func Init() {
+
+}
+
+func (x *Peripheral) Retain() {
+//NOTE: ns.ObjectAtIndex() calls SetFinalizer for us, which will be a problem
+//later when we call GC(), so we always first clear the finalizer before
+//setting a new one.
+	runtime.SetFinalizer(x.p, nil)
+	x.p.Retain()
+	x.p.GC()
+}
+
 func peripheralName(p *ns.CBPeripheral) string {
 	var ret string
 	nsname := p.Name()
@@ -68,125 +89,8 @@ func newPeripheral(x *ns.CBPeripheral) Peripheral {
 	return ret
 }
 
-type PeripheralListItem struct {
-	p    Peripheral
-	seen time.Time
-}
-
-type Peripherals struct {
-	items []PeripheralListItem
-	sync.Mutex
-}
-
-type ConnectionListItem struct {
-	p     Peripheral
-	state chan string
-}
-
-type Connections struct {
-	items []ConnectionListItem
-	close chan struct{}
-	sync.Mutex
-}
-
-func (c *Connections) UpdateState(p Peripheral, s string) {
-	var ch chan string
-	c.Lock()
-	for _, item := range c.items {
-		if p.Identifier == item.p.Identifier {
-			ch = item.state
-		}
-	}
-	c.Unlock()
-	ch <- s
-}
-
-func (ps *Peripherals) Add(x Peripheral) bool {
-	ps.Lock()
-	defer ps.Unlock()
-	found := false
-	for n, item := range ps.items {
-		if item.p.Identifier == x.Identifier {
-			item.p = x
-			item.seen = time.Now()
-			ps.items[n] = item
-			found = true
-			break
-		}
-	}
-	if found {
-		return false
-	}
-	//take ownership of this Objective-C object
-	x.p.Retain()
-	runtime.SetFinalizer(x.p, nil)
-	x.p.GC()
-	item := PeripheralListItem{p: x, seen: time.Now()}
-	ps.items = append(ps.items, item)
-	return true
-}
-
-func (cs *Connections) Add(x ConnectionListItem) bool {
-	cs.Lock()
-	defer cs.Unlock()
-	found := false
-	for _, item := range cs.items {
-		if item.p.Identifier == x.p.Identifier {
-			// are we allowed to have multiple connections to the same peripheral?
-			return false
-		}
-	}
-	if found {
-		return false
-	}
-	cs.items = append(cs.items, x)
-	return true
-}
-
-type UpdateStateEvent struct {
-	State string
-}
-
-type DiscoverPeripheralEvent struct {
-	Peripheral Peripheral
-}
-
-type DiscoverServiceEvent struct {
-	Peripheral Peripheral
-	Gatt gatt.Service
-	Service *ns.CBService
-}
-
-type DiscoverCharacteristicEvent struct {
-	Peripheral Peripheral
-	Gatt gatt.Characteristic
-	Service *ns.CBService
-	Characteristic *ns.CBCharacteristic
-}
-
-type UpdateValueEvent struct {
-	Peripheral Peripheral
-	Characteristic *ns.CBCharacteristic
-	Data []byte
-}
-
-type ConnectEvent struct {
-	Peripheral Peripheral
-}
-type ConnectTimeoutEvent struct {
-	Peripheral Peripheral
-}
-
-type UpdageValueEvent struct {
-	Peripheral Peripheral
-	Characteristic gatt.Characteristic
-}
-
-func (b *BLE) Events() chan interface{} {
-	return b.events
-}
-
-func stringState(x ns.CBManagerState) string {
+func (b *BLE) stringState() string {
+	x := b.state
 	switch x {
 	case (ns.CBManagerState)(ns.CBManagerStateResetting):
 		return "resetting"
@@ -205,10 +109,16 @@ func stringState(x ns.CBManagerState) string {
 	}
 }
 
-func (b *BLE) State() string {
-	b.Lock()
-	defer b.Unlock()
-	return stringState(b.state)
+func (b *BLE) readyToScan() bool {
+	return b.state == (ns.CBManagerState)(ns.CBManagerStatePoweredOn)
+}
+
+func (b *BLE) scan() {
+	b.cm.ScanForPeripheralsWithServices(nil, nil)
+}
+
+func (b *BLE) stopScan() {
+	b.cm.StopScan()
 }
 
 func (b *BLE) setState(x ns.CBManagerState) {
@@ -217,38 +127,18 @@ func (b *BLE) setState(x ns.CBManagerState) {
 	b.state = x
 	if b.ready && b.wantScan {
 		fmt.Printf("Go: Scanning\n")
-		b.cm.ScanForPeripheralsWithServices(nil, nil)
+		b.scan()
 		b.wantScan = false
 	}
 }
 
-func (b *BLE) Scan() {
-	b.Lock()
-	defer b.Unlock()
-	if b.state != (ns.CBManagerState)(ns.CBManagerStatePoweredOn) {
-		b.wantScan = true
-	} else {
-		b.peripherals.Lock()
-		b.peripherals.items = b.peripherals.items[:0]
-		b.peripherals.Unlock()
-		fmt.Printf("Go: Scanning\n")
-		b.cm.ScanForPeripheralsWithServices(nil, nil)
-	}
-}
-
-func (b *BLE) StopScan() {
-	b.Lock()
-	if !b.ready {
-		b.Unlock()
-		return
-	}
-	b.Unlock()
-	fmt.Printf("Go: stopping scan\n")
-	b.cm.StopScan()
+func (b *BLE) connectPeripheral(x Peripheral) {
+	fmt.Printf("BLE.Connect(): calling cm.ConnectPeripheral(%p)\n", x.p.Ptr())
+	b.cm.ConnectPeripheral(x.p, nil)
 }
 
 func CancelConnection(p Peripheral) {
-	b := pdLookup[p.p.Ptr()]
+	b := peripheralLookup(p)
 	if b == nil {
 		return
 	}
@@ -266,99 +156,24 @@ func CancelConnection(p Peripheral) {
 	}
 }
 
-func connectTracker(b *BLE, x ConnectionListItem) bool {
-	fmt.Printf("connectTracker(): %s\n", x.p.Name)
-	b.connections.Lock()
-	for _, item := range b.connections.items {
-		if item.p.Identifier == x.p.Identifier {
-			fmt.Printf("connectTracker(): already connecting to %s\n", x.p.Name)
-			b.connections.Unlock()
-			return true
-		}
-	}
-	b.connections.items = append(b.connections.items, x)
-	b.connections.Unlock()
-	fmt.Printf("BLE.Connect(): calling cm.ConnectPeripheral(%p)\n", x.p.p.Ptr())
-	b.cm.ConnectPeripheral(x.p.p, nil)
-
-	cancel := func() {
-		b.cm.CancelPeripheralConnection(x.p.p)
-		b.connections.Lock()
-		for n, item := range b.connections.items {
-			if item.p.Identifier == x.p.Identifier {
-				b.connections.items = append(b.connections.items[:n], b.connections.items[n+1:]...)
-			}
-		}
-		b.connections.Unlock()
-	}
-
-	go func() {
-		tick := time.NewTicker(time.Second * 5)
-		select {
-		case <-b.connections.close:
-			fmt.Printf("connectTracker(): Closing connection to %s\n", x.p.Name)
-			b.cm.CancelPeripheralConnection(x.p.p)
-		case <-tick.C:
-			fmt.Printf("connectTracker(): Connection to %s timed out\n", x.p.Name)
-			cancel()
-			b.events <- ConnectTimeoutEvent{x.p}
-		case state := <-x.state:
-			if state == "cancel" {
-				cancel()
-			}
-			fmt.Printf("connectTracker(): state %s\n", state)
-		}
-	}()
-	return true
-}
-
-func (b *BLE) Connect(p Peripheral) bool {
-	b.Lock()
-	if !b.ready {
-		b.Unlock()
-		fmt.Printf("--BLE not ready\n")
-		return false
-	}
-	b.Unlock()
-	if p.p == nil {
-		fmt.Printf("RetrievePeripheralsWithIdentifiers\n")
-		ps := b.cm.RetrievePeripheralsWithIdentifiers(ns.NSArrayWithObjects(ns.NSUUIDAlloc().InitWithUUIDString(ns.NSStringWithGoString(p.Identifier))))
-		if x := (int)(ps.Count()); x > 0 {
-			fmt.Printf("--found %d\n", x)
-			cbp := ps.ObjectAtIndex(0).CBPeripheral()
-//NOTE: ns.ObjectAtIndex() calls SetFinalizer for us, which will be a problem
-//later when we call GC(), so we first clear the finalizer here.
-			runtime.SetFinalizer(cbp, nil)
-			p = newPeripheral(cbp)
-		} else {
-			fmt.Printf("--none found\n")
-			return false
-		}
-	}
-	item := ConnectionListItem{p, make(chan string)}
-	fmt.Printf("BLE.Connect() calling connectTracker\n")
-	return connectTracker(b, item)
-}
-
-func Disconnect(p Peripheral) {
-	b := pdLookup[p.p.Ptr()]
-	found := false
-	b.connections.Lock()
-	for i, item := range b.connections.items {
-		if item.p.Identifier == p.Identifier {
-			found = true
-			b.connections.items = append(b.connections.items[:i], b.connections.items[i+1:]...)
-			break
-		}
-	}
-	b.connections.Unlock()
-	if !found {
-		return
-	}
+func (b *BLE) cancelConnection(p Peripheral) {
 	b.cm.CancelPeripheralConnection(p.p)
 }
 
-func updateState(c *ns.CBCentralManager) {
+func (b *BLE) knownPeripheral(p Peripheral) (Peripheral, bool) {
+	fmt.Printf("RetrievePeripheralsWithIdentifiers\n")
+	ps := b.cm.RetrievePeripheralsWithIdentifiers(ns.NSArrayWithObjects(ns.NSUUIDAlloc().InitWithUUIDString(ns.NSStringWithGoString(p.Identifier))))
+	if x := (int)(ps.Count()); x > 0 {
+		fmt.Printf("--found %d\n", x)
+		cbp := ps.ObjectAtIndex(0).CBPeripheral()
+		return newPeripheral(cbp), true
+	} else {
+		fmt.Printf("--none found\n")
+		return Peripheral{}, false
+	}
+}
+
+func didUpdateState(c *ns.CBCentralManager) {
 	b := cdLookup[c.Ptr()]
 	st := c.CBManager.State()
 	if st == (ns.CBManagerState)(ns.CBManagerStatePoweredOn) {
@@ -378,17 +193,17 @@ func updateState(c *ns.CBCentralManager) {
 		}
 	}
 	b.setState(st)
-	b.events <- UpdateStateEvent{State: stringState(st)}
+	b.events <- UpdateStateEvent{State: b.stringState()}
 }
 
-func discoverPeripheral(c *ns.CBCentralManager, p *ns.CBPeripheral, d *ns.NSDictionary, rssi *ns.NSNumber) {
+func didDiscoverPeripheral(c *ns.CBCentralManager, p *ns.CBPeripheral, d *ns.NSDictionary, rssi *ns.NSNumber) {
 	b := cdLookup[c.Ptr()]
 	peripheral := newPeripheral(p)
 	peripheral.RSSI = (int)(rssi.IntValue())
-	_discoverPeripheral(b, peripheral)
+	_didDiscoverPeripheral(b, peripheral)
 }
 
-func _discoverPeripheral(b *BLE, peripheral Peripheral) {
+func _didDiscoverPeripheral(b *BLE, peripheral Peripheral) {
 	if peripheral.Name == "" {
 		return
 	}
@@ -398,7 +213,7 @@ func _discoverPeripheral(b *BLE, peripheral Peripheral) {
 	}
 }
 
-func connectPeripheral(c *ns.CBCentralManager, p *ns.CBPeripheral) {
+func didConnectPeripheral(c *ns.CBCentralManager, p *ns.CBPeripheral) {
 	fmt.Printf("Did connect peripheral\n")
 	b := cdLookup[c.Ptr()]
 
@@ -428,7 +243,7 @@ func connectPeripheral(c *ns.CBCentralManager, p *ns.CBPeripheral) {
 
 	b.connections.UpdateState(peripheral, "connected")
 	b.events <- ConnectEvent{peripheral}
-	fmt.Printf("Go: connectPeripheral returning\n")
+	fmt.Printf("Go: didConnectPeripheral returning\n")
 }
 
 func (x Peripheral) DiscoverServices() {
@@ -440,7 +255,7 @@ func (x Peripheral) DiscoverServices() {
 	p.DiscoverServices(nil)
 }
 
-func discoverServices(p *ns.CBPeripheral, e *ns.NSError) {
+func didDiscoverServices(p *ns.CBPeripheral, e *ns.NSError) {
 	b := pdLookup[p.Ptr()]
 	fmt.Printf("Did discover services\n")
 	p.Services().ObjectEnumerator().ForIn(func(o *ns.Id) bool {
@@ -453,7 +268,7 @@ func discoverServices(p *ns.CBPeripheral, e *ns.NSError) {
 		}
 		return true
 	})
-	fmt.Printf("Go: discoverServices returning\n")
+	fmt.Printf("Go: didDiscoverServices returning\n")
 }
 
 func hr(d *ns.NSData) int {
@@ -473,7 +288,7 @@ func (p Peripheral) DiscoverCharacteristics(serv *ns.CBService) {
 	p.p.DiscoverCharacteristics(nil, serv)
 }
 
-func discoverCharacteristics(p *ns.CBPeripheral, s *ns.CBService, e *ns.NSError) {
+func didDiscoverCharacteristics(p *ns.CBPeripheral, s *ns.CBService, e *ns.NSError) {
 	b := pdLookup[p.Ptr()]
 	fmt.Printf("Did discover characteristics\n")
 	s.Characteristics().ObjectEnumerator().ForIn(func(o *ns.Id) bool {
@@ -488,14 +303,14 @@ func discoverCharacteristics(p *ns.CBPeripheral, s *ns.CBService, e *ns.NSError)
 		}
 		return true
 	})
-	fmt.Printf("Go: discoverCharacteristics returning\n")
+	fmt.Printf("Go: didDiscoverCharacteristics returning\n")
 }
 
 func (p Peripheral) SetNotifyValue(c *ns.CBCharacteristic) {
 	p.p.SetNotifyValue(1, c)
 }
 
-func updateValue(p *ns.CBPeripheral, chr *ns.CBCharacteristic, e *ns.NSError) {
+func didUpdateValue(p *ns.CBPeripheral, chr *ns.CBCharacteristic, e *ns.NSError) {
 	b := pdLookup[p.Ptr()]
 	v := chr.Value()
 	b.events <-UpdateValueEvent{
@@ -505,33 +320,21 @@ func updateValue(p *ns.CBPeripheral, chr *ns.CBCharacteristic, e *ns.NSError) {
 	}
 }
 
-var (
-	hrm_uuid  *ns.CBUUID
-	hrv_uuid  *ns.CBUUID
-	info_uuid *ns.CBUUID
-
-	gble *BLE
-)
-
 func NewBLE() *BLE {
 	ps := Peripherals{items: make([]PeripheralListItem, 0)}
 	ble := &BLE{events: make(chan interface{}), peripherals: ps}
-	gble = ble
 
 	queue := ns.DispatchQueueCreate(ns.CharWithGoString("go_hrm_queue"), nil)
 
 	cd := ns.CBDelegateAlloc()
 
-	cd.CentralManagerDidUpdateStateCallback(updateState)
-	cd.CentralManagerDidDiscoverPeripheralCallback(discoverPeripheral)
-	cd.CentralManagerDidConnectPeripheralCallback(connectPeripheral)
-	cd.PeripheralDidDiscoverServicesCallback(discoverServices)
-	cd.PeripheralDidDiscoverCharacteristicsForServiceCallback(discoverCharacteristics)
-	cd.PeripheralDidUpdateValueForCharacteristicCallback(updateValue)
+	cd.CentralManagerDidUpdateStateCallback(didUpdateState)
+	cd.CentralManagerDidDiscoverPeripheralCallback(didDiscoverPeripheral)
+	cd.CentralManagerDidConnectPeripheralCallback(didConnectPeripheral)
+	cd.PeripheralDidDiscoverServicesCallback(didDiscoverServices)
+	cd.PeripheralDidDiscoverCharacteristicsForServiceCallback(didDiscoverCharacteristics)
+	cd.PeripheralDidUpdateValueForCharacteristicCallback(didUpdateValue)
 
-	hrm_uuid = ns.CBUUIDWithGoString("180D")
-	hrv_uuid = ns.CBUUIDWithGoString("2A37")
-	info_uuid = ns.CBUUIDWithGoString("180A")
 
 	ble.cd = cd
 	if cdLookup == nil {